fix M

.gitignore

@@ -1,7 +1,6 @@
 __pycache__/
 *.py[cod]
 junk/
-.vscode
 .ipynb_checkpoints/
 tools/ansible/inventory/hawaii.yml
 tools/ansible/inventory/peppermint.yml
@@ -17,6 +16,7 @@ dist/
 *.egg-info/
 .venv/
 venv/
+docs/_build/
 .codex
 
 

.vscode/extensions.json

@@ -0,0 +1,11 @@
+{
+  "recommendations": [
+    "swyddfa.esbonio",
+    "ms-python.python",
+    "ms-python.vscode-pylance",
+    "ms-python.debugpy",
+    "tamasfe.even-better-toml",
+    "redhat.vscode-yaml",
+    "DavidAnson.vscode-markdownlint"
+  ]
+}

.vscode/settings.json

@@ -0,0 +1,18 @@
+{
+  "esbonio.sphinx.pythonCommand": "${venv:.venv}/bin/python",
+  "esbonio.sphinx.buildCommand": [
+    "sphinx-build",
+    "-b",
+    "html",
+    "docs",
+    "docs/_build/html"
+  ],
+  "python.defaultInterpreterPath": "${workspaceFolder}/.venv/bin/python",
+  "python.testing.pytestEnabled": true,
+  "python.testing.pytestArgs": [
+    "--ignore=tests/legacy",
+    "--ignore=tests/support",
+    "tests"
+  ],
+  "restructuredtext.confPath": "${workspaceFolder}/docs"
+}

docs/Makefile

@@ -0,0 +1,21 @@
+SPHINXOPTS       ?=
+VENV_SPHINXBUILD = ../.venv/bin/sphinx-build
+SPHINXBUILD      ?= $(if $(wildcard $(VENV_SPHINXBUILD)),$(VENV_SPHINXBUILD),sphinx-build)
+SOURCEDIR        = .
+BUILDDIR         = _build
+
+.PHONY: help clean html linkcheck
+
+help:
+	@echo "Please use 'make <target>' where <target> is one of"
+	@echo "  html       to make standalone HTML files"
+	@echo "  linkcheck  to check all external links for integrity"
+
+clean:
+	rm -rf "$(BUILDDIR)"
+
+html:
+	@$(SPHINXBUILD) -b html "$(SOURCEDIR)" "$(BUILDDIR)/html" $(SPHINXOPTS)
+
+linkcheck:
+	@$(SPHINXBUILD) -b linkcheck "$(SOURCEDIR)" "$(BUILDDIR)/linkcheck" $(SPHINXOPTS)

docs/api.rst

@@ -0,0 +1,31 @@
+API Reference
+=============
+
+This section exposes selected modules that are useful when working on tests,
+diagnostics, process execution, metadata editing, and file probing.
+
+CLI Helpers
+-----------
+
+.. automodule:: ffx.cli
+   :members:
+   :undoc-members:
+
+Process Helpers
+---------------
+
+.. automodule:: ffx.process
+   :members:
+   :undoc-members:
+
+File Probing
+------------
+
+.. automodule:: ffx.file_properties
+
+Metadata Editing
+----------------
+
+.. automodule:: ffx.metadata_editor
+   :members:
+   :undoc-members:

docs/conf.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from importlib.metadata import PackageNotFoundError, version as package_version
+from pathlib import Path
+import sys
+
+
+ROOT_DIR = Path(__file__).resolve().parents[1]
+SRC_DIR = ROOT_DIR / "src"
+sys.path.insert(0, str(SRC_DIR))
+
+project = "FFX"
+author = "javanaut@maveno.de"
+copyright = "2026, Maveno"
+
+try:
+    release = package_version("ffx")
+except PackageNotFoundError:
+    release = "0.0.0"
+version = release
+
+extensions = [
+    "sphinx.ext.autodoc",
+    "sphinx.ext.napoleon",
+    "sphinx.ext.viewcode",
+    "sphinx_copybutton",
+]
+
+source_suffix = {
+    ".rst": "restructuredtext",
+}
+
+templates_path = ["_templates"]
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
+
+html_theme = "sphinx_rtd_theme"
+html_title = "FFX"
+html_static_path = []
+
+autodoc_typehints = "description"
+autodoc_member_order = "bysource"
+napoleon_google_docstring = True
+napoleon_numpy_docstring = True
+

docs/development.rst

@@ -0,0 +1,50 @@
+Development
+===========
+
+The repo-local ``.venv`` is the preferred environment for contributors working
+on tests or documentation:
+
+.. code-block:: sh
+
+   tests/prepare.sh
+
+The preparation script installs the package in editable mode with both test and
+documentation extras:
+
+.. code-block:: text
+
+   .[test,docs]
+
+Run Tests
+---------
+
+Run the modern pytest suite:
+
+.. code-block:: sh
+
+   .venv/bin/python -m pytest --ignore=tests/legacy --ignore=tests/support tests
+
+The legacy harness remains available separately and is intentionally not part of
+the default pytest run.
+
+Build Docs
+----------
+
+Build HTML documentation:
+
+.. code-block:: sh
+
+   .venv/bin/sphinx-build -b html docs docs/_build/html
+
+The same command is wrapped by the Sphinx ``Makefile``:
+
+.. code-block:: sh
+
+   make -C docs html
+
+VS Code
+-------
+
+The repository includes ``.vscode/extensions.json`` with recommended
+extensions, including Esbonio for Sphinx language-server support. The workspace
+settings point Python tooling and Esbonio at the repo-local ``.venv``.

docs/file_formats.md

@@ -1,170 +0,0 @@
-# File Formats
-
-This document captures source-file-format notes that complement the normative
-requirements in `requirements/source_file_formats.md`.
-
-The first documented format is a Matroska source that carries styled ASS/SSA
-subtitle streams together with embedded font attachments.
-
-## Styled ASS In Matroska With Embedded Fonts
-
-These files are typically `.mkv` releases where subtitle rendering quality
-depends on keeping both parts of the subtitle package together:
-
-- one or more subtitle streams with codec `ass`
-- one or more attachment streams that embed font files used by those subtitles
-
-This matters because ASS subtitles are not plain text subtitles in the narrow
-WebVTT sense. They can carry layout, styling, positioning, karaoke, signs, and
-other typesetting effects. If the matching embedded fonts are lost, consumers
-can still see subtitle text but the intended styling and sometimes glyph
-coverage can be degraded.
-
-For FFX this format is special because the ASS subtitle streams should remain
-normally editable and mappable, while the related font attachments should be
-transported unchanged.
-
-## Observed Sample
-
-Assessment date: `2026-04-17`
-
-Observed sample file:
-
-- `tests/assets/boruto_s01e283_ssa.mkv`
-
-Commands used for assessment:
-
-```bash
-ffprobe tests/assets/boruto_s01e283_ssa.mkv
-ffprobe -hide_banner -show_format -show_streams -of json tests/assets/boruto_s01e283_ssa.mkv
-```
-
-Observed stream layout:
-
-| Stream index | Kind | Key details |
-| --- | --- | --- |
-| `0` | video | `codec_name=h264` |
-| `1` | audio | `codec_name=aac`, `language=jpn` |
-| `2` | subtitle | `codec_name=ass`, `language=ger`, default |
-| `3` | subtitle | `codec_name=ass`, `language=eng` |
-| `4`-`13` | attachment | `tags.mimetype=font/ttf`, `.ttf` filenames |
-
-Observed attachment filenames:
-
-- `AmazonEmberTanuki-Italic.ttf`
-- `AmazonEmberTanuki-Regular.ttf`
-- `Arial.ttf`
-- `Arial Bold.ttf`
-- `Georgia.ttf`
-- `Times New Roman.ttf`
-- `Times New Roman Bold.ttf`
-- `Trebuchet MS.ttf`
-- `Verdana.ttf`
-- `Verdana Bold.ttf`
-
-Important probe behavior from the real sample:
-
-- Plain `ffprobe` lists the font streams as `Attachment: none`.
-- Plain `ffprobe` also prints warnings such as `Could not find codec
-  parameters for stream 4 (Attachment: none): unknown codec` and later
-  `Unsupported codec with id 0 for input stream ...`.
-- The JSON produced by `FileProperties.FFPROBE_COMMAND_TOKENS`
-  (`ffprobe -hide_banner -show_format -show_streams -of json`) still exposes
-  the attachment streams clearly through `codec_type="attachment"` and the
-  attachment tags.
-- In that JSON, the attachment streams do not expose `codec_name`.
-
-This last point is important for FFX: robust detection must not depend on
-attachment `codec_name` being present.
-
-## Detection Guidance
-
-Current known indicators for this format are:
-
-- one or more subtitle streams with `codec_type="subtitle"` and
-  `codec_name="ass"`
-- one or more attachment streams with `codec_type="attachment"`
-- attachment tags that identify embedded fonts, especially
-  `tags.mimetype="font/ttf"`
-- attachment filenames that end in `.ttf`
-
-The pattern can vary. FFX should therefore treat the above as a cluster of
-signals rather than an exact signature tied to one file.
-
-Inference from the observed sample plus FFmpeg documentation:
-
-- MIME matching should not be limited to `font/ttf` alone.
-- The Boruto sample uses `font/ttf`.
-- FFmpeg's Matroska attachment example uses
-  `mimetype=application/x-truetype-font` for a `.ttf` attachment.
-- Detection should therefore normalize multiple TTF-like MIME values rather
-  than depend on a single exact string.
-
-## Processing Expectations In FFX
-
-The format-specific requirements live in
-`requirements/source_file_formats.md`. In practical terms, FFX should:
-
-- recognize the ASS-plus-font-attachment pattern even when attachment probe
-  data is incomplete
-- tell the operator that the pattern was detected and that special handling is
-  being used
-- reject sidecar subtitle import for such sources, because converting or
-  replacing these subtitle tracks with ordinary external text subtitles would
-  break the intended subtitle package
-- continue to allow normal manipulation of the ASS subtitle tracks themselves
-- preserve the font attachment streams unchanged
-
-## FFmpeg Notes
-
-Relevant FFmpeg documentation confirms several behaviors that line up with
-FFX's needs:
-
-- FFmpeg documents `-attach` as adding an attachment stream to the output, and
-  explicitly names Matroska fonts used in subtitle rendering as an example.
-- FFmpeg documents attachment streams as regular streams that are created after
-  the mapped media streams.
-- FFmpeg documents `-dump_attachment` for extracting attachment streams, which
-  is useful for debugging or validating a source file's embedded fonts.
-- FFmpeg's Matroska example requires a `mimetype` metadata tag for attached
-  fonts, which is consistent with using attachment tags as detection signals.
-- FFmpeg also notes that attachments are implemented as codec extradata. That
-  helps explain why probe output for attachment streams can look different from
-  ordinary audio, video, and subtitle streams.
-
-Implication for FFX:
-
-- Attachment preservation is not an optional cosmetic feature for this format.
-  It is part of preserving the subtitle package correctly.
-
-## Jellyfin Notes
-
-Jellyfin's documentation also supports keeping this format intact:
-
-- Jellyfin's subtitle compatibility table lists `ASS/SSA` as supported in
-  `MKV` and not supported in `MP4`.
-- Jellyfin notes that when subtitles must be transcoded, they are either
-  converted to a supported format or burned into the video, and burning them in
-  is the most CPU-intensive path.
-- Jellyfin's subtitle-extraction example for `SSA/ASS` first dumps attachment
-  streams and then extracts the ASS subtitle stream, which reflects the real
-  relationship between ASS subtitles and embedded fonts in MKV releases.
-- Jellyfin's font documentation says text-based subtitles require fonts to
-  render properly.
-- Jellyfin's configuration documentation says the web client uses configured
-  fallback fonts for ASS subtitles when other fonts such as MKV attachments or
-  client-side fonts are not available.
-
-Inference from the Jellyfin compatibility tables:
-
-- Keeping this subtitle format in Matroska is the safest interoperability
-  choice for Jellyfin consumers.
-- Converting the subtitle payload to WebVTT would lose styled ASS behavior.
-- Dropping the attachment streams would force client or fallback font
-  substitution and can change appearance or glyph coverage.
-
-## References
-
-- FFmpeg documentation: https://ffmpeg.org/ffmpeg.html
-- Jellyfin codec support: https://jellyfin.org/docs/general/clients/codec-support/
-- Jellyfin configuration and fonts: https://jellyfin.org/docs/general/administration/configuration/

docs/file_formats.rst

@@ -0,0 +1,192 @@
+File Formats
+============
+
+This document captures source-file-format notes that complement the normative
+requirements in ``requirements/source_file_formats.md``.
+
+The first documented format is a Matroska source that carries styled ASS/SSA
+subtitle streams together with embedded font attachments.
+
+Styled ASS In Matroska With Embedded Fonts
+------------------------------------------
+
+These files are typically ``.mkv`` releases where subtitle rendering quality
+depends on keeping both parts of the subtitle package together:
+
+* one or more subtitle streams with codec ``ass``
+* one or more attachment streams that embed font files used by those subtitles
+
+This matters because ASS subtitles are not plain text subtitles in the narrow
+WebVTT sense. They can carry layout, styling, positioning, karaoke, signs, and
+other typesetting effects. If the matching embedded fonts are lost, consumers
+can still see subtitle text but the intended styling and sometimes glyph
+coverage can be degraded.
+
+For FFX this format is special because the ASS subtitle streams should remain
+normally editable and mappable, while the related font attachments should be
+transported unchanged.
+
+Observed Sample
+---------------
+
+Assessment date: ``2026-04-17``
+
+Observed sample file:
+
+* ``tests/assets/boruto_s01e283_ssa.mkv``
+
+Commands used for assessment:
+
+.. code-block:: bash
+
+   ffprobe tests/assets/boruto_s01e283_ssa.mkv
+   ffprobe -hide_banner -show_format -show_streams -of json tests/assets/boruto_s01e283_ssa.mkv
+
+Observed stream layout:
+
+.. list-table::
+   :header-rows: 1
+
+   * - Stream index
+     - Kind
+     - Key details
+   * - ``0``
+     - video
+     - ``codec_name=h264``
+   * - ``1``
+     - audio
+     - ``codec_name=aac``, ``language=jpn``
+   * - ``2``
+     - subtitle
+     - ``codec_name=ass``, ``language=ger``, default
+   * - ``3``
+     - subtitle
+     - ``codec_name=ass``, ``language=eng``
+   * - ``4``-``13``
+     - attachment
+     - ``tags.mimetype=font/ttf``, ``.ttf`` filenames
+
+Observed attachment filenames:
+
+* ``AmazonEmberTanuki-Italic.ttf``
+* ``AmazonEmberTanuki-Regular.ttf``
+* ``Arial.ttf``
+* ``Arial Bold.ttf``
+* ``Georgia.ttf``
+* ``Times New Roman.ttf``
+* ``Times New Roman Bold.ttf``
+* ``Trebuchet MS.ttf``
+* ``Verdana.ttf``
+* ``Verdana Bold.ttf``
+
+Important probe behavior from the real sample:
+
+* Plain ``ffprobe`` lists the font streams as ``Attachment: none``.
+* Plain ``ffprobe`` also prints warnings such as ``Could not find codec
+  parameters for stream 4 (Attachment: none): unknown codec`` and later
+  ``Unsupported codec with id 0 for input stream ...``.
+* The JSON produced by ``FileProperties.FFPROBE_COMMAND_TOKENS``
+  (``ffprobe -hide_banner -show_format -show_streams -of json``) still exposes
+  the attachment streams clearly through ``codec_type="attachment"`` and the
+  attachment tags.
+* In that JSON, the attachment streams do not expose ``codec_name``.
+
+This last point is important for FFX: robust detection must not depend on
+attachment ``codec_name`` being present.
+
+Detection Guidance
+------------------
+
+Current known indicators for this format are:
+
+* one or more subtitle streams with ``codec_type="subtitle"`` and
+  ``codec_name="ass"``
+* one or more attachment streams with ``codec_type="attachment"``
+* attachment tags that identify embedded fonts, especially
+  ``tags.mimetype="font/ttf"``
+* attachment filenames that end in ``.ttf``
+
+The pattern can vary. FFX should therefore treat the above as a cluster of
+signals rather than an exact signature tied to one file.
+
+Inference from the observed sample plus FFmpeg documentation:
+
+* MIME matching should not be limited to ``font/ttf`` alone.
+* The Boruto sample uses ``font/ttf``.
+* FFmpeg's Matroska attachment example uses
+  ``mimetype=application/x-truetype-font`` for a ``.ttf`` attachment.
+* Detection should therefore normalize multiple TTF-like MIME values rather
+  than depend on a single exact string.
+
+Processing Expectations In FFX
+------------------------------
+
+The format-specific requirements live in
+``requirements/source_file_formats.md``. In practical terms, FFX should:
+
+* recognize the ASS-plus-font-attachment pattern even when attachment probe data
+  is incomplete
+* tell the operator that the pattern was detected and that special handling is
+  being used
+* reject sidecar subtitle import for such sources, because converting or
+  replacing these subtitle tracks with ordinary external text subtitles would
+  break the intended subtitle package
+* continue to allow normal manipulation of the ASS subtitle tracks themselves
+* preserve the font attachment streams unchanged
+
+FFmpeg Notes
+------------
+
+Relevant FFmpeg documentation confirms several behaviors that line up with
+FFX's needs:
+
+* FFmpeg documents ``-attach`` as adding an attachment stream to the output, and
+  explicitly names Matroska fonts used in subtitle rendering as an example.
+* FFmpeg documents attachment streams as regular streams that are created after
+  the mapped media streams.
+* FFmpeg documents ``-dump_attachment`` for extracting attachment streams, which
+  is useful for debugging or validating a source file's embedded fonts.
+* FFmpeg's Matroska example requires a ``mimetype`` metadata tag for attached
+  fonts, which is consistent with using attachment tags as detection signals.
+* FFmpeg also notes that attachments are implemented as codec extradata. That
+  helps explain why probe output for attachment streams can look different from
+  ordinary audio, video, and subtitle streams.
+
+Implication for FFX:
+
+* Attachment preservation is not an optional cosmetic feature for this format.
+  It is part of preserving the subtitle package correctly.
+
+Jellyfin Notes
+--------------
+
+Jellyfin's documentation also supports keeping this format intact:
+
+* Jellyfin's subtitle compatibility table lists ``ASS/SSA`` as supported in
+  ``MKV`` and not supported in ``MP4``.
+* Jellyfin notes that when subtitles must be transcoded, they are either
+  converted to a supported format or burned into the video, and burning them in
+  is the most CPU-intensive path.
+* Jellyfin's subtitle-extraction example for ``SSA/ASS`` first dumps attachment
+  streams and then extracts the ASS subtitle stream, which reflects the real
+  relationship between ASS subtitles and embedded fonts in MKV releases.
+* Jellyfin's font documentation says text-based subtitles require fonts to
+  render properly.
+* Jellyfin's configuration documentation says the web client uses configured
+  fallback fonts for ASS subtitles when other fonts such as MKV attachments or
+  client-side fonts are not available.
+
+Inference from the Jellyfin compatibility tables:
+
+* Keeping this subtitle format in Matroska is the safest interoperability choice
+  for Jellyfin consumers.
+* Converting the subtitle payload to WebVTT would lose styled ASS behavior.
+* Dropping the attachment streams would force client or fallback font
+  substitution and can change appearance or glyph coverage.
+
+References
+----------
+
+* FFmpeg documentation: https://ffmpeg.org/ffmpeg.html
+* Jellyfin codec support: https://jellyfin.org/docs/general/clients/codec-support/
+* Jellyfin configuration and fonts: https://jellyfin.org/docs/general/administration/configuration/

docs/index.rst

@@ -0,0 +1,25 @@
+FFX Documentation
+=================
+
+FFX is a local command-line and Textual terminal UI for inspecting TV episode
+files, storing normalization rules, and converting media into predictable
+archive-ready outputs.
+
+This documentation covers operator setup, day-to-day command usage, contributor
+workflow, format-specific notes, and generated API references for the smaller
+utility modules.
+
+.. toctree::
+   :maxdepth: 2
+   :caption: User Guide
+
+   installation
+   usage
+   file_formats
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contributor Guide
+
+   development
+   api

docs/installation.rst

@@ -0,0 +1,52 @@
+Installation
+============
+
+FFX is designed for a Linux-like workstation with local command execution. The
+runtime media tools must be available on ``PATH``:
+
+* ``ffmpeg``
+* ``ffprobe``
+* ``cpulimit``
+
+User Bundle
+-----------
+
+The persistent user installation is prepared with the two-step flow described in
+the project README:
+
+.. code-block:: sh
+
+   bash tools/setup.sh
+   bash tools/configure_workstation.sh
+
+``tools/setup.sh`` creates the long-lived bundle virtualenv at
+``~/.local/share/ffx.venv`` and exposes the ``ffx`` command. The workstation
+script checks system tools and seeds local config directories.
+
+Local Test And Docs Environment
+-------------------------------
+
+Contributor test and documentation work uses the repo-local virtualenv:
+
+.. code-block:: sh
+
+   tests/prepare.sh
+
+The script creates ``.venv``, installs FFX in editable mode with test and docs
+extras, and verifies the Sphinx toolchain. Use check-only mode when you only
+want to inspect readiness:
+
+.. code-block:: sh
+
+   tests/prepare.sh --check
+
+Documentation Build
+-------------------
+
+After preparation, build the documentation with:
+
+.. code-block:: sh
+
+   .venv/bin/sphinx-build -b html docs docs/_build/html
+
+The generated site starts at ``docs/_build/html/index.html``.

docs/make.bat

@@ -0,0 +1,42 @@
+@ECHO OFF
+
+pushd %~dp0
+
+if "%SPHINXBUILD%" == "" if exist ..\.venv\Scripts\sphinx-build.exe (
+	set SPHINXBUILD=..\.venv\Scripts\sphinx-build.exe
+)
+if "%SPHINXBUILD%" == "" set SPHINXBUILD=sphinx-build
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo The 'sphinx-build' command was not found. Make sure Sphinx is installed,
+	echo then set SPHINXBUILD to the full path if needed.
+	exit /b 1
+)
+
+if "%1" == "" goto help
+if "%1" == "html" goto html
+if "%1" == "linkcheck" goto linkcheck
+echo.
+echo Unknown target "%1".
+goto help
+
+:html
+%SPHINXBUILD% -b html %SOURCEDIR% %BUILDDIR%\html %SPHINXOPTS%
+goto end
+
+:linkcheck
+%SPHINXBUILD% -b linkcheck %SOURCEDIR% %BUILDDIR%\linkcheck %SPHINXOPTS%
+goto end
+
+:help
+echo.
+echo Please use 'make.bat ^<target^>' where ^<target^> is one of
+echo   html       to make standalone HTML files
+echo   linkcheck  to check all external links for integrity
+
+:end
+popd

docs/usage.rst

@@ -0,0 +1,97 @@
+Usage
+=====
+
+FFX exposes a single ``ffx`` command with subcommands for inspection,
+conversion, metadata editing, setup, and maintenance.
+
+Inspect Files
+-------------
+
+Open the inspection workflow for one or more files:
+
+.. code-block:: sh
+
+   ffx inspect /path/to/episode.mkv
+
+Print resolved season-shift mappings without opening the TUI:
+
+.. code-block:: sh
+
+   ffx inspect --shift /path/to/episode.mkv
+
+Convert Files
+-------------
+
+Convert one or more source files using stored rules where available:
+
+.. code-block:: sh
+
+   ffx convert /path/to/episode.mkv
+
+Useful overrides include:
+
+* ``--no-pattern`` to skip database pattern matching
+* ``--show``, ``--season``, and ``--episode`` for explicit episode identity
+* ``--output-directory`` for generated output placement
+* ``--subtitle-directory`` for source-basename sidecar subtitle imports
+* ``--subtitle-prefix`` for explicit or configured-prefix subtitle imports
+* ``--subtitle-extension`` to select the imported sidecar format (default:
+  ``vtt``)
+* ``--yes`` to accept a valid partial sidecar set without prompting
+* ``--copy-video`` or ``--copy-audio`` to preserve selected stream types
+* ``--rename-only`` for filename normalization without media rewriting
+
+Directory-only subtitle import matches the source basename. For example,
+``A2_t01.mkv`` discovers files such as ``A2_t01_2_deu_DEF.vtt`` in the
+provided directory:
+
+.. code-block:: sh
+
+   ffx convert --subtitle-directory /path/to/subtitles A2_t01.mkv
+
+Select a different sidecar set by extension, with or without the leading dot:
+
+.. code-block:: sh
+
+   ffx convert --subtitle-directory /path/to/subtitles \
+     --subtitle-extension .mkv A2_t01.mkv
+
+When only some source subtitle tracks have matching sidecar files, conversion
+asks for confirmation. Use ``--yes`` to substitute that valid subset without
+prompting. ``--yes`` also permits this case when ``--no-prompt`` is set.
+
+Manage Shows And Patterns
+-------------------------
+
+Open the Textual interface for show and pattern management:
+
+.. code-block:: sh
+
+   ffx shows
+
+Extract Streams
+---------------
+
+Extract streams from a file:
+
+.. code-block:: sh
+
+   ffx unmux /path/to/episode.mkv
+
+For subtitle-only extraction:
+
+.. code-block:: sh
+
+   ffx unmux --subtitles-only --label show-name /path/to/episode.mkv
+
+Detect Crop
+-----------
+
+Ask FFmpeg to suggest crop parameters:
+
+.. code-block:: sh
+
+   ffx cropdetect /path/to/episode.mkv
+
+The default sampling window is controlled by the application defaults and can be
+overridden with command options.

pyproject.toml

@@ -31,6 +31,12 @@ Issues = "https://gitea.maveno.de/Javanaut/ffx/issues"
 test = [
   "pytest",
 ]
+docs = [
+  "esbonio",
+  "sphinx",
+  "sphinx-copybutton",
+  "sphinx-rtd-theme",
+]
 
 [build-system]
 requires = [

requirements/subtrack_mapping.md

@@ -46,6 +46,13 @@ Secondary source: `tests/legacy/`, used only to clarify intent and reveal gaps.
 - `SUBTRACK_MAPPING-0016`: Metadata for a substituted target track shall be merged from the regular source track and the separate source file when available.
 - `SUBTRACK_MAPPING-0017`: If the separate source file provides a metadata field that is also present on the regular source track, the separate source file value shall win in the target output.
 - `SUBTRACK_MAPPING-0018`: If a metadata field is absent from the separate source file, the system shall fall back to the corresponding metadata from the regular source track or target schema rewrite rules.
+- `SUBTRACK_MAPPING-0019`: When `ffx convert` receives an explicit subtitle directory without a subtitle prefix, it shall discover sidecar files using the source media basename as the filename prefix.
+- `SUBTRACK_MAPPING-0020`: Basename-driven subtitle discovery shall first filter regular files by the exact `<source-basename>_` filename prefix and the configured subtitle extension.
+- `SUBTRACK_MAPPING-0021`: `--subtitle-extension` shall accept an extension with or without a leading dot, default to `vtt`, and apply to both basename-driven and explicit-prefix subtitle discovery.
+- `SUBTRACK_MAPPING-0022`: Basename-driven sidecar filenames shall identify the target subtitle track using the existing `<prefix>_<stream-index>_<language>[_<disposition>].<extension>` filename contract.
+- `SUBTRACK_MAPPING-0023`: A complete, valid basename-driven sidecar set shall proceed without confirmation and shall report the discovered substitutions to the operator.
+- `SUBTRACK_MAPPING-0024`: An incomplete but otherwise valid basename-driven sidecar set shall require confirmation before substituting only the represented subtitle tracks. `--yes` shall supply that confirmation without prompting. With `--no-prompt` and without `--yes`, conversion shall fail with an explanation instead.
+- `SUBTRACK_MAPPING-0025`: Basename-driven discovery shall fail before conversion when the filtered set contains too many files, malformed filenames, duplicate stream indices, or stream indices that do not identify subtitle tracks in the active media descriptor.
 
 ## Acceptance
 
@@ -57,6 +64,9 @@ Secondary source: `tests/legacy/`, used only to clarify intent and reveal gaps.
 - If target-track metadata is rewritten after reordering, it is written onto the correct source-derived logical track rather than the track that merely occupies the same final output position.
 - Invalid target-to-source references fail deterministically before the conversion job is launched.
 - If a separate source file substitutes one target track, that track keeps its target slot and ordering while metadata is merged with separate-file values taking precedence when both sides provide the same field.
+- Given `A2_t01.mkv` and an explicit subtitle directory containing `A2_t01_2_deu_DEF.vtt`, `A2_t01_3_eng.vtt`, and `A2_t01_4_eng.vtt`, directory-only subtitle import recognizes and substitutes all three tracks without prompting.
+- Selecting `--subtitle-extension mkv` or `--subtitle-extension .mkv` selects the equivalent basename-matched `.mkv` sidecar set instead of the default `.vtt` set.
+- Given an incomplete but valid basename-matched sidecar set, `--yes` proceeds with only the represented subtitle substitutions, including when `--no-prompt` is also set.
 - A test proving subtrack mapping must assert at least one of: exact `source_index` to output-order mapping, omission of named source tracks, or preservation of per-track metadata after reorder.
 
 ## Test Notes

src/ffx/cli.py

@@ -41,13 +41,17 @@ CPU_OPTION_HELP = (
     + "Omit to disable; 0 also disables."
 )
 SUBTITLE_DIRECTORY_OPTION_HELP = (
-    "Load subtitles from here. When omitted and --subtitle-prefix is set, "
+    "Load subtitles from here. Without --subtitle-prefix, match the source filename "
+    + "basename. When omitted and --subtitle-prefix is set, "
     + "FFX uses the configured subtitlesDirectory base path plus the prefix as a subdirectory."
 )
 SUBTITLE_PREFIX_OPTION_HELP = (
     "Subtitle filename prefix. Requires --subtitle-directory, or a configured "
     + "subtitlesDirectory base path that contains a matching <prefix>/ subdirectory."
 )
+SUBTITLE_EXTENSION_OPTION_HELP = (
+    "External subtitle filename extension. A leading dot is optional."
+)
 UNMUX_OUTPUT_DIRECTORY_OPTION_HELP = (
     "Write extracted streams here. When omitted together with --subtitles-only and "
     + "--label, FFX uses the configured subtitlesDirectory base path plus the label."
@@ -96,6 +100,18 @@ def normalizeCpuOption(ctx, param, value):
         raise click.BadParameter(str(ex)) from ex
 
 
+def normalizeSubtitleExtension(ctx, param, value):
+    normalizedExtension = str(value).strip().lower()
+    if normalizedExtension.startswith('.'):
+        normalizedExtension = normalizedExtension[1:]
+    if not normalizedExtension or not normalizedExtension.isalnum():
+        raise click.BadParameter(
+            "Subtitle extension must contain only letters and numbers, "
+            + "with an optional leading dot."
+        )
+    return normalizedExtension
+
+
 def parseCutOptionValue(value) -> tuple[int, int] | None:
     if value is None:
         return None
@@ -146,11 +162,21 @@ def resolveSubtitleImportOptions(context, subtitleDirectory, subtitlePrefix):
         else ''
     )
 
-    if not resolvedSubtitlePrefix:
-        return False, resolvedSubtitleDirectory, resolvedSubtitlePrefix
-
     if resolvedSubtitleDirectory:
-        return True, resolvedSubtitleDirectory, resolvedSubtitlePrefix
+        if not os.path.isdir(resolvedSubtitleDirectory):
+            raise click.ClickException(
+                "The provided subtitle directory does not exist: "
+                + resolvedSubtitleDirectory
+            )
+        return (
+            True,
+            resolvedSubtitleDirectory,
+            resolvedSubtitlePrefix,
+            not resolvedSubtitlePrefix,
+        )
+
+    if not resolvedSubtitlePrefix:
+        return False, resolvedSubtitleDirectory, resolvedSubtitlePrefix, False
 
     configuredSubtitlesBaseDirectory = context['config'].getSubtitlesDirectoryPath()
     if not configuredSubtitlesBaseDirectory:
@@ -170,7 +196,85 @@ def resolveSubtitleImportOptions(context, subtitleDirectory, subtitlePrefix):
             + resolvedSubtitleDirectory
         )
 
-    return True, resolvedSubtitleDirectory, resolvedSubtitlePrefix
+    return True, resolvedSubtitleDirectory, resolvedSubtitlePrefix, False
+
+
+def importExternalSubtitles(
+    context,
+    mediaDescriptor,
+    sourceFileBasename,
+    season,
+    episode,
+    preserveDispositions=False,
+):
+    matchSourceBasename = context['subtitle_match_source_basename']
+    subtitlePrefix = (
+        sourceFileBasename
+        if matchSourceBasename
+        else context['subtitle_prefix']
+    )
+
+    try:
+        importResult = mediaDescriptor.importSubtitles(
+            context['subtitle_directory'],
+            subtitlePrefix,
+            season,
+            episode,
+            preserve_dispositions=preserveDispositions,
+            extension=context['subtitle_extension'],
+            strict=matchSourceBasename,
+        )
+    except (OSError, ValueError) as ex:
+        raise click.ClickException(
+            f"External subtitle discovery failed for '{sourceFileBasename}': {ex}"
+        ) from ex
+
+    if not matchSourceBasename:
+        return importResult
+
+    importedTrackIndices = importResult['imported_track_indices']
+    missingTrackIndices = importResult['missing_track_indices']
+    extension = context['subtitle_extension']
+    importedDescription = (
+        ', '.join(f"#{index}" for index in importedTrackIndices)
+        if importedTrackIndices
+        else 'none'
+    )
+    click.echo(
+        f"External subtitle scan for '{sourceFileBasename}': found "
+        + f"{importResult['candidate_count']} .{extension} file(s); "
+        + f"matched subtitle tracks {importedDescription}."
+    )
+
+    if not missingTrackIndices:
+        return importResult
+
+    missingDescription = ', '.join(f"#{index}" for index in missingTrackIndices)
+    incompleteMessage = (
+        f"External subtitle files are missing for subtitle tracks "
+        + f"{missingDescription} in '{sourceFileBasename}'."
+    )
+    if context.get('yes', False):
+        click.echo(
+            incompleteMessage
+            + " Continuing with the matching subtitle files because --yes is set."
+        )
+        return importResult
+
+    if context['no_prompt']:
+        raise click.ClickException(
+            incompleteMessage
+            + " Partial subtitle substitution requires confirmation, but --no-prompt is set."
+        )
+
+    click.echo(incompleteMessage)
+    if not click.confirm(
+        "Continue and substitute only the subtitle tracks with matching files?",
+        default=False,
+    ):
+        raise click.ClickException("External subtitle substitution aborted by user.")
+
+    return importResult
 
 
 def resolveUnmuxOutputDirectory(context, outputDirectory, subtitlesOnly, label):
@@ -181,7 +285,10 @@ def resolveUnmuxOutputDirectory(context, outputDirectory, subtitlesOnly, label):
     )
     resolvedLabel = str(label).strip()
 
-    if resolvedOutputDirectory or not subtitlesOnly or not resolvedLabel:
+    if resolvedOutputDirectory:
+        return resolvedOutputDirectory, True
+
+    if not subtitlesOnly or not resolvedLabel:
         return resolvedOutputDirectory, False
 
     configuredSubtitlesBaseDirectory = context['config'].getSubtitlesDirectoryPath()
@@ -194,6 +301,59 @@ def resolveUnmuxOutputDirectory(context, outputDirectory, subtitlesOnly, label):
     return os.path.join(configuredSubtitlesBaseDirectory, resolvedLabel), True
 
 
+def confirmUnmuxOutputDirectoryCreation(outputDirectory):
+    message = (
+        "Create unmux output directory and missing parents: "
+        + str(outputDirectory)
+    )
+
+    if not sys.stdin.isatty():
+        return click.confirm(message, default=True)
+
+    click.echo(f"{message} [Y/n]: ", nl=False)
+    while True:
+        char = click.getchar()
+        if char in ('\r', '\n'):
+            click.echo()
+            return True
+
+        normalizedChar = char.lower()
+        if normalizedChar == 'y':
+            click.echo(char)
+            return True
+        if normalizedChar == 'n':
+            click.echo(char)
+            return False
+        if char in ('\x03', '\x04'):
+            raise click.Abort()
+
+        click.echo("\nPlease respond with 'y' or 'n': ", nl=False)
+
+
+def ensureUnmuxOutputDirectory(context, outputDirectory):
+    resolvedOutputDirectory = os.path.expanduser(str(outputDirectory).strip())
+    if not resolvedOutputDirectory:
+        return False
+
+    if os.path.isdir(resolvedOutputDirectory):
+        return False
+
+    if os.path.exists(resolvedOutputDirectory):
+        raise click.ClickException(
+            "Unmux output path exists but is not a directory: "
+            + resolvedOutputDirectory
+        )
+
+    if context.get('dry_run', False):
+        return False
+
+    if not confirmUnmuxOutputDirectoryCreation(resolvedOutputDirectory):
+        raise click.ClickException("Unmux output directory creation aborted by user.")
+
+    os.makedirs(resolvedOutputDirectory, exist_ok=True)
+    return True
+
+
 def resolveIndicatorDigitLengths(context=None, showDescriptor=None):
     from ffx.show_descriptor import ShowDescriptor
 
@@ -753,14 +913,14 @@ def unmux(ctx,
     ctx.obj['resource_limits']['cpu_limit'] = cpu
     ctx.obj['resource_limits']['cpu_percent'] = cpu
 
-    output_directory, create_output_directory = resolveUnmuxOutputDirectory(
+    output_directory, requires_output_directory = resolveUnmuxOutputDirectory(
         ctx.obj,
         output_directory,
         subtitles_only,
         label,
     )
-    if create_output_directory and existingSourcePaths and not ctx.obj.get('dry_run', False):
-        os.makedirs(output_directory, exist_ok=True)
+    if requires_output_directory and existingSourcePaths:
+        ensureUnmuxOutputDirectory(ctx.obj, output_directory)
 
     shiftedSeasonController = ShiftedSeasonController(ctx.obj)
 
@@ -974,6 +1134,14 @@ def checkUniqueDispositions(context, mediaDescriptor: MediaDescriptor):
 
 @click.option('--subtitle-directory', type=str, default='', help=SUBTITLE_DIRECTORY_OPTION_HELP)
 @click.option('--subtitle-prefix', type=str, default='', help=SUBTITLE_PREFIX_OPTION_HELP)
+@click.option(
+    '--subtitle-extension',
+    type=str,
+    default='vtt',
+    callback=normalizeSubtitleExtension,
+    show_default=True,
+    help=SUBTITLE_EXTENSION_OPTION_HELP,
+)
 
 @click.option('--language', type=str, multiple=True, help='Set stream language. Use format <stream index>:<3 letter iso code>')
 @click.option('--title', type=str, multiple=True, help='Set stream title. Use format <stream index>:<title>')
@@ -1034,6 +1202,12 @@ def checkUniqueDispositions(context, mediaDescriptor: MediaDescriptor):
 @click.option("--dont-pass-dispositions", is_flag=True, default=False)
 
 @click.option("--no-prompt", is_flag=True, default=False)
+@click.option(
+    "--yes",
+    is_flag=True,
+    default=False,
+    help="Confirm partial external subtitle substitution without prompting.",
+)
 @click.option("--no-signature", is_flag=True, default=False)
 @click.option("--keep-mkvmerge-metadata", is_flag=True, default=False)
 
@@ -1070,6 +1244,7 @@ def convert(ctx,
 
             subtitle_directory,
             subtitle_prefix,
+            subtitle_extension,
 
             language,
             title,
@@ -1108,6 +1283,7 @@ def convert(ctx,
             no_pattern,
             dont_pass_dispositions,
             no_prompt,
+            yes,
             no_signature,
             keep_mkvmerge_metadata,
             
@@ -1162,6 +1338,7 @@ def convert(ctx,
     context['use_tmdb'] = not no_tmdb
     context['use_pattern'] = not no_pattern
     context['no_prompt'] = no_prompt
+    context['yes'] = yes
     context['no_signature'] = no_signature
     context['keep_mkvmerge_metadata'] = keep_mkvmerge_metadata
 
@@ -1180,6 +1357,7 @@ def convert(ctx,
         context['import_subtitles'],
         resolvedSubtitleDirectory,
         resolvedSubtitlePrefix,
+        context['subtitle_match_source_basename'],
     ) = resolveSubtitleImportOptions(
         context,
         subtitle_directory,
@@ -1188,6 +1366,7 @@ def convert(ctx,
     if context['import_subtitles']:
         context['subtitle_directory'] = resolvedSubtitleDirectory
         context['subtitle_prefix'] = resolvedSubtitlePrefix
+        context['subtitle_extension'] = subtitle_extension
 
 
     existingSourcePaths = [p for p in paths if os.path.isfile(p) and p.split('.')[-1] in SUPPORTED_INPUT_FILE_EXTENSIONS]
@@ -1431,10 +1610,13 @@ def convert(ctx,
             currentShowDescriptor = None
 
             if context['import_subtitles']:
-                sourceMediaDescriptor.importSubtitles(context['subtitle_directory'],
-                                                        context['subtitle_prefix'],
+                importExternalSubtitles(
+                    context,
+                    sourceMediaDescriptor,
+                    sourceFileBasename,
                     showSeason,
-                                                        showEpisode)
+                    showEpisode,
+                )
 
             if cliOverrides:
                 sourceMediaDescriptor.applyOverrides(cliOverrides)
@@ -1478,11 +1660,14 @@ def convert(ctx,
 
 
             if context['import_subtitles']:
-                targetMediaDescriptor.importSubtitles(context['subtitle_directory'],
-                                                        context['subtitle_prefix'],
+                importExternalSubtitles(
+                    context,
+                    targetMediaDescriptor,
+                    sourceFileBasename,
                     showSeason,
                     showEpisode,
-                                                        preserve_dispositions=True)
+                    preserveDispositions=True,
+                )
 
             # ctx.obj['logger'].debug(f"tmd subindices: {[t.getIndex() for t in targetMediaDescriptor.getAllTrackDescriptors()]} {[t.getSubIndex() for t in targetMediaDescriptor.getAllTrackDescriptors()]}  {[t.getDispositionFlag(TrackDisposition.DEFAULT) for t in targetMediaDescriptor.getAllTrackDescriptors()]}")
             ctx.obj['logger'].debug(f"tmd subindices: {[t.getIndex() for t in targetMediaDescriptor.getTrackDescriptors()]} {[t.getSubIndex() for t in targetMediaDescriptor.getTrackDescriptors()]}  {[t.getDispositionFlag(TrackDisposition.DEFAULT) for t in targetMediaDescriptor.getTrackDescriptors()]}")

src/ffx/media_descriptor.py

@@ -431,10 +431,13 @@ class MediaDescriptor:
             importedFilePath = td.getExternalSourceFilePath()
 
             if importedFilePath:
-
-                self.__logger.info(f"Substituting subtitle stream #{td.getIndex()} "
+                substitutionMessage = (
+                    f"Substituting subtitle stream #{td.getIndex()} "
                     + f"({td.getType().label()}:{td.getSubIndex()}) "
-                                    + f"with import from file {td.getExternalSourceFilePath()}")
+                    + f"with import from file {td.getExternalSourceFilePath()}"
+                )
+                click.echo(substitutionMessage)
+                self.__logger.debug(substitutionMessage)
 
                 importFileTokens += [
                     "-i",
@@ -524,25 +527,72 @@ class MediaDescriptor:
         return inputMappingTokens
 
 
-    def searchSubtitleFiles(self, searchDirectory, prefix):
-
-        sesld_match = re.compile(f"{prefix}_{MediaDescriptor.SEASON_EPISODE_STREAM_LANGUAGE_DISPOSITIONS_MATCH}")
-        sld_match = re.compile(f"{prefix}_{MediaDescriptor.STREAM_LANGUAGE_DISPOSITIONS_MATCH}")
-
-        subtitleFileDescriptors = []
-
-        for subtitleFilename in os.listdir(searchDirectory):
-            if subtitleFilename.startswith(prefix) and subtitleFilename.endswith(
-                "." + MediaDescriptor.SUBTITLE_FILE_EXTENSION
+    def searchSubtitleFiles(
+        self,
+        searchDirectory,
+        prefix,
+        extension=SUBTITLE_FILE_EXTENSION,
+        strict=False,
     ):
 
-                sesld_result = sesld_match.search(subtitleFilename)
-                sld_result = None if not sesld_result is None else sld_match.search(subtitleFilename)
+        normalizedExtension = str(extension).strip().lower()
+        if normalizedExtension.startswith('.'):
+            normalizedExtension = normalizedExtension[1:]
+        escapedPrefix = re.escape(prefix)
+        sesld_match = re.compile(
+            f"{escapedPrefix}_{MediaDescriptor.SEASON_EPISODE_STREAM_LANGUAGE_DISPOSITIONS_MATCH}"
+        )
+        sld_match = re.compile(
+            f"{escapedPrefix}_{MediaDescriptor.STREAM_LANGUAGE_DISPOSITIONS_MATCH}"
+        )
 
-                if not sesld_result is None:
+        subtitleFileDescriptors = []
+        subtitleFilenames = []
+
+        for subtitleFilename in sorted(os.listdir(searchDirectory)):
+            subtitleFilePath = os.path.join(searchDirectory, subtitleFilename)
+            subtitleFilenameStem, subtitleFilenameExtension = os.path.splitext(
+                subtitleFilename
+            )
+            if (
+                os.path.isfile(subtitleFilePath)
+                and subtitleFilenameStem.startswith(prefix + '_')
+                and subtitleFilenameExtension.lower() == '.' + normalizedExtension
+            ):
+                subtitleFilenames.append(subtitleFilename)
+
+        expectedSubtitleTrackIndices = {
+            subtitleTrack.getIndex()
+            for subtitleTrack in self.getSubtitleTracks()
+        }
+        if strict and len(subtitleFilenames) > len(expectedSubtitleTrackIndices):
+            raise ValueError(
+                f"Found {len(subtitleFilenames)} matching .{normalizedExtension} files "
+                + f"for {len(expectedSubtitleTrackIndices)} subtitle tracks."
+            )
+
+        for subtitleFilename in subtitleFilenames:
+            subtitleFilenameStem = os.path.splitext(subtitleFilename)[0]
+            sesld_result = (
+                None
+                if strict
+                else sesld_match.fullmatch(subtitleFilenameStem)
+            )
+            sld_result = (
+                None
+                if sesld_result is not None
+                else sld_match.fullmatch(subtitleFilenameStem)
+            )
+
+            if strict and sesld_result is None and sld_result is None:
+                raise ValueError(
+                    f"Subtitle filename does not match the expected pattern: "
+                    + subtitleFilename
+                )
+
+            if sesld_result is not None:
 
                 subtitleFilePath = os.path.join(searchDirectory, subtitleFilename)
-                    if os.path.isfile(subtitleFilePath):
 
                 subtitleFileDescriptor = {}
                 subtitleFileDescriptor["path"] = subtitleFilePath
@@ -556,17 +606,18 @@ class MediaDescriptor:
                 numCaptGroups = len(dispCaptGroups)
                 if numCaptGroups > 4:
                     for groupIndex in range(numCaptGroups - 4):
-                                disp = TrackDisposition.fromIndicator(dispCaptGroups[groupIndex + 4])
+                        disp = TrackDisposition.fromIndicator(
+                            dispCaptGroups[groupIndex + 4]
+                        )
                         if disp is not None:
                             dispSet.add(disp)
                 subtitleFileDescriptor["disposition_set"] = dispSet
 
                 subtitleFileDescriptors.append(subtitleFileDescriptor)
 
-                if not sld_result is None:
+            if sld_result is not None:
 
                 subtitleFilePath = os.path.join(searchDirectory, subtitleFilename)
-                    if os.path.isfile(subtitleFilePath):
 
                 subtitleFileDescriptor = {}
                 subtitleFileDescriptor["path"] = subtitleFilePath
@@ -578,13 +629,52 @@ class MediaDescriptor:
                 numCaptGroups = len(dispCaptGroups)
                 if numCaptGroups > 2:
                     for groupIndex in range(numCaptGroups - 2):
-                                disp = TrackDisposition.fromIndicator(dispCaptGroups[groupIndex + 2])
+                        disp = TrackDisposition.fromIndicator(
+                            dispCaptGroups[groupIndex + 2]
+                        )
                         if disp is not None:
                             dispSet.add(disp)
                 subtitleFileDescriptor["disposition_set"] = dispSet
 
                 subtitleFileDescriptors.append(subtitleFileDescriptor)
 
+        if strict:
+            discoveredTrackIndices = [
+                descriptor['index'] for descriptor in subtitleFileDescriptors
+            ]
+            duplicateTrackIndices = sorted(
+                {
+                    trackIndex
+                    for trackIndex in discoveredTrackIndices
+                    if discoveredTrackIndices.count(trackIndex) > 1
+                }
+            )
+            if duplicateTrackIndices:
+                duplicateDescription = ', '.join(
+                    f"#{index}" for index in duplicateTrackIndices
+                )
+                raise ValueError(
+                    "Multiple external subtitle files refer to subtitle track(s) "
+                    + duplicateDescription
+                    + "."
+                )
+
+            unexpectedTrackIndices = sorted(
+                set(discoveredTrackIndices) - expectedSubtitleTrackIndices
+            )
+            if unexpectedTrackIndices:
+                unexpectedDescription = ', '.join(
+                    f"#{index}" for index in unexpectedTrackIndices
+                )
+                expectedDescription = ', '.join(
+                    f"#{index}" for index in sorted(expectedSubtitleTrackIndices)
+                ) or 'none'
+                raise ValueError(
+                    "External subtitle track index pattern does not match the media "
+                    + f"subtitle tracks: found {unexpectedDescription}; "
+                    + f"expected a subset of {expectedDescription}."
+                )
+
 
         self.__logger.debug(f"searchSubtitleFiles(): Available subtitle files {subtitleFileDescriptors}")
 
@@ -598,12 +688,19 @@ class MediaDescriptor:
         season: int = -1,
         episode: int = -1,
         preserve_dispositions: bool = False,
+        extension: str = SUBTITLE_FILE_EXTENSION,
+        strict: bool = False,
     ):
         
         # click.echo(f"Season: {season} Episode: {episode}")
         self.__logger.debug(f"importSubtitles(): Season: {season} Episode: {episode}")
 
-        availableFileSubtitleDescriptors = self.searchSubtitleFiles(searchDirectory, prefix)
+        availableFileSubtitleDescriptors = self.searchSubtitleFiles(
+            searchDirectory,
+            prefix,
+            extension=extension,
+            strict=strict,
+        )
         
         self.__logger.debug(f"importSubtitles(): availableFileSubtitleDescriptors: {availableFileSubtitleDescriptors}")
 
@@ -616,7 +713,8 @@ class MediaDescriptor:
                 [
                     d
                     for d in availableFileSubtitleDescriptors
-                    if ((season == -1 and episode == -1)
+                    if (strict
+                        or (season == -1 and episode == -1)
                         or (
                             d.get("season") == int(season)
                             and d.get("episode") == int(episode)
@@ -630,6 +728,7 @@ class MediaDescriptor:
 
         self.__logger.debug(f"importSubtitles(): matchingSubtitleFileDescriptors: {matchingSubtitleFileDescriptors}")
 
+        importedTrackIndices = []
         for msfd in matchingSubtitleFileDescriptors:
             matchingSubtitleTrackDescriptor = [s for s in subtitleTracks if s.getIndex() == msfd["index"]]
             if matchingSubtitleTrackDescriptor:
@@ -643,6 +742,19 @@ class MediaDescriptor:
                 matchingTrack.getTags()["language"] = msfd["language"]
                 if msfd["disposition_set"] and not preserve_dispositions:
                     matchingTrack.setDispositionSet(msfd["disposition_set"])
+                importedTrackIndices.append(matchingTrack.getIndex())
+
+        expectedTrackIndices = sorted(
+            subtitleTrack.getIndex() for subtitleTrack in subtitleTracks
+        )
+        importedTrackIndices = sorted(set(importedTrackIndices))
+        return {
+            "candidate_count": len(availableFileSubtitleDescriptors),
+            "imported_track_indices": importedTrackIndices,
+            "missing_track_indices": sorted(
+                set(expectedTrackIndices) - set(importedTrackIndices)
+            ),
+        }
 
 
     def getConfiguration(self, label: str = ''):

tests/integration/subtrack_mapping/test_cli_bundle.py

@@ -421,6 +421,59 @@ class SubtrackMappingBundleTests(unittest.TestCase):
         self.assertIn("external subtitle payload", extracted_subtitle)
         self.assertNotIn("embedded subtitle payload", extracted_subtitle)
 
+    def test_subtitle_directory_without_prefix_uses_source_basename(self):
+        source_filename = "basename_substitute.mkv"
+        subtitle_directory = self.workdir / "sidecars"
+        subtitle_directory.mkdir()
+        source_path = create_source_fixture(
+            self.workdir,
+            source_filename,
+            [
+                SourceTrackSpec(TrackType.VIDEO, identity="video-0"),
+                SourceTrackSpec(TrackType.AUDIO, identity="audio-1", language="eng"),
+                SourceTrackSpec(
+                    TrackType.SUBTITLE,
+                    identity="embedded-subtitle",
+                    language="eng",
+                    subtitle_lines=("embedded subtitle payload",),
+                ),
+            ],
+        )
+        write_vtt(
+            subtitle_directory / "basename_substitute_2_deu_DEF.vtt",
+            ("external subtitle payload",),
+        )
+
+        completed = run_ffx_convert(
+            self.workdir,
+            self.home_dir,
+            self.database_path,
+            "--video-encoder",
+            "copy",
+            "--no-pattern",
+            "--no-tmdb",
+            "--no-prompt",
+            "--no-signature",
+            "--subtitle-directory",
+            str(subtitle_directory),
+            str(source_path),
+        )
+        self.assertCompleted(completed)
+        self.assertIn("matched subtitle tracks #2", completed.stdout)
+        self.assertIn("Substituting subtitle stream #2", completed.stdout)
+
+        output_path = expected_output_path(self.workdir, source_filename)
+        subtitle_stream = [
+            stream
+            for stream in ffprobe_json(output_path)["streams"]
+            if stream["codec_type"] == "subtitle"
+        ][0]
+        self.assertEqual("deu", get_tag(subtitle_stream, "language"))
+
+        extracted_subtitle = extract_first_subtitle_text(self.workdir, output_path)
+        self.assertIn("external subtitle payload", extracted_subtitle)
+        self.assertNotIn("embedded subtitle payload", extracted_subtitle)
+
     def test_subtitle_prefix_uses_configured_base_directory_when_directory_is_omitted(self):
         source_filename = "substitute_default_s01e01.mkv"
         subtitle_prefix = "substitute_default"

tests/integration/test_cli_unmux.py

@@ -35,7 +35,13 @@ if pytest is not None:
 SRC_ROOT = Path(__file__).resolve().parents[2] / "src"
 
 
-def run_ffx_unmux(workdir: Path, home_dir: Path, database_path: Path, *args: str) -> subprocess.CompletedProcess[str]:
+def run_ffx_unmux(
+    workdir: Path,
+    home_dir: Path,
+    database_path: Path,
+    *args: str,
+    input_text: str | None = None,
+) -> subprocess.CompletedProcess[str]:
     env = os.environ.copy()
     env["HOME"] = str(home_dir)
     existing_pythonpath = env.get("PYTHONPATH", "")
@@ -50,7 +56,14 @@ def run_ffx_unmux(workdir: Path, home_dir: Path, database_path: Path, *args: str
         "unmux",
         *args,
     ]
-    return subprocess.run(command, cwd=workdir, env=env, capture_output=True, text=True)
+    return subprocess.run(
+        command,
+        cwd=workdir,
+        env=env,
+        capture_output=True,
+        input=input_text,
+        text=True,
+    )
 
 
 class UnmuxCliTests(unittest.TestCase):
@@ -164,6 +177,7 @@ class UnmuxCliTests(unittest.TestCase):
             "--label",
             "dball",
             str(source_path),
+            input_text="y\n",
         )
         self.assertCompleted(completed)
 

tests/prepare.sh

@@ -0,0 +1,471 @@
+#!/usr/bin/env bash
+
+set -u
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+ROOT_DIR="$(cd -- "${SCRIPT_DIR}/.." && pwd)"
+VENV_DIR="${FFX_TEST_VENV_DIR:-${ROOT_DIR}/.venv}"
+VENV_BIN_DIR="${VENV_DIR}/bin"
+VENV_PYTHON="${VENV_BIN_DIR}/python"
+VENV_PIP="${VENV_BIN_DIR}/pip"
+
+CHECK_ONLY=0
+READINESS_FAILURES=0
+INSTALL_FAILURES=0
+
+MISSING_REQUIRED_SYSTEM=()
+
+COLOR_RESET=""
+COLOR_GREEN=""
+COLOR_YELLOW=""
+COLOR_RED=""
+
+if [ -t 1 ]; then
+    COLOR_RESET="$(printf '\033[0m')"
+    COLOR_GREEN="$(printf '\033[32m')"
+    COLOR_YELLOW="$(printf '\033[33m')"
+    COLOR_RED="$(printf '\033[31m')"
+fi
+
+usage() {
+    cat <<EOF
+Usage: $(basename "$0") [--check] [--help]
+
+Prepare the repo-local FFX test environment at:
+  ${VENV_DIR}
+
+Actions:
+  - verify or install required system commands for tests
+  - create or reuse the repo-local test virtualenv
+  - install this repository into the venv with Python test and docs extras
+
+Options:
+  --check  Report readiness only. Do not create, install, or modify.
+  --help   Show this help text.
+
+Environment overrides:
+  FFX_TEST_VENV_DIR  Override the test virtualenv path. Defaults to ${ROOT_DIR}/.venv.
+
+Notes:
+  - This script prepares a project-local test environment, not the persistent user bundle.
+  - The persistent bundle setup remains owned by tools/setup.sh.
+EOF
+}
+
+status_ok() {
+    printf '%sok%s' "${COLOR_GREEN}" "${COLOR_RESET}"
+}
+
+status_warn() {
+    printf '%swarn%s' "${COLOR_YELLOW}" "${COLOR_RESET}"
+}
+
+status_fail() {
+    printf '%sfailed%s' "${COLOR_RED}" "${COLOR_RESET}"
+}
+
+report_component() {
+    local level="$1"
+    local label="$2"
+    local detail="$3"
+    local rendered_status=""
+
+    case "${level}" in
+        ok)
+            rendered_status="$(status_ok)"
+            ;;
+        warn)
+            rendered_status="$(status_warn)"
+            ;;
+        *)
+            rendered_status="$(status_fail)"
+            ;;
+    esac
+
+    printf '[%s] %s%s\n' "${rendered_status}" "${label}" "${detail:+: $detail}"
+}
+
+command_exists() {
+    command -v "$1" >/dev/null 2>&1
+}
+
+check_python_venv_support() {
+    python3 -m venv --help >/dev/null 2>&1
+}
+
+check_system_command() {
+    command_exists "$1"
+}
+
+check_venv_python() {
+    [ -x "${VENV_PYTHON}" ]
+}
+
+check_venv_pip() {
+    check_venv_python && "${VENV_PIP}" --version >/dev/null 2>&1
+}
+
+check_venv_ffx() {
+    check_venv_python && "${VENV_PYTHON}" -m ffx version >/dev/null 2>&1
+}
+
+check_venv_pytest() {
+    check_venv_python && "${VENV_PYTHON}" -m pytest --version >/dev/null 2>&1
+}
+
+check_venv_sphinx() {
+    check_venv_python && "${VENV_BIN_DIR}/sphinx-build" --version >/dev/null 2>&1
+}
+
+check_venv_docs_packages() {
+    check_venv_python && "${VENV_PYTHON}" - <<'PY' >/dev/null 2>&1
+import esbonio
+import sphinx
+import sphinx_rtd_theme
+PY
+}
+
+check_editable_install() {
+    check_venv_python && FFX_REPO_ROOT="${ROOT_DIR}" "${VENV_PYTHON}" - <<'PY' >/dev/null 2>&1
+from __future__ import annotations
+
+import os
+from pathlib import Path
+import ffx
+
+repo_root = Path(os.environ["FFX_REPO_ROOT"]).resolve()
+package_path = Path(ffx.__file__).resolve()
+
+raise SystemExit(0 if repo_root in package_path.parents else 1)
+PY
+}
+
+check_python_environment_ready() {
+    check_venv_python &&
+        check_venv_pip &&
+        check_venv_pytest &&
+        check_venv_sphinx &&
+        check_venv_docs_packages &&
+        check_venv_ffx &&
+        check_editable_install
+}
+
+command_detail() {
+    command -v "$1" || printf "command '%s' not found" "$1"
+}
+
+python_venv_detail() {
+    if check_python_venv_support; then
+        printf 'python3 -m venv is available'
+    else
+        printf 'python3 venv support is unavailable'
+    fi
+}
+
+venv_python_detail() {
+    if check_venv_python; then
+        printf '%s' "${VENV_PYTHON}"
+    else
+        printf 'missing %s' "${VENV_PYTHON}"
+    fi
+}
+
+venv_pip_detail() {
+    if check_venv_pip; then
+        "${VENV_PIP}" --version
+    else
+        printf 'missing pip in %s' "${VENV_DIR}"
+    fi
+}
+
+venv_ffx_detail() {
+    if check_venv_ffx; then
+        printf 'ffx import and CLI entry are available'
+    else
+        printf 'ffx is not installed in %s' "${VENV_DIR}"
+    fi
+}
+
+venv_pytest_detail() {
+    if check_venv_pytest; then
+        "${VENV_PYTHON}" -m pytest --version 2>/dev/null | head -n 1
+    else
+        printf 'pytest is not installed in %s' "${VENV_DIR}"
+    fi
+}
+
+venv_sphinx_detail() {
+    if check_venv_sphinx; then
+        "${VENV_BIN_DIR}/sphinx-build" --version 2>&1
+    else
+        printf 'sphinx-build is not installed in %s' "${VENV_DIR}"
+    fi
+}
+
+venv_docs_packages_detail() {
+    if check_venv_docs_packages; then
+        printf 'Sphinx, Read the Docs theme, and Esbonio packages are importable'
+    else
+        printf 'one or more docs packages are missing in %s' "${VENV_DIR}"
+    fi
+}
+
+editable_install_detail() {
+    if check_editable_install; then
+        printf 'ffx resolves from %s' "${ROOT_DIR}"
+    else
+        printf 'ffx does not resolve from the project source tree'
+    fi
+}
+
+report_required_command() {
+    local label="$1"
+    local command_name="$2"
+
+    if check_system_command "${command_name}"; then
+        report_component ok "${label}" "$(command_detail "${command_name}")"
+    else
+        report_component failed "${label}" "$(command_detail "${command_name}")"
+        MISSING_REQUIRED_SYSTEM+=("${command_name}")
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+}
+
+print_system_status() {
+    MISSING_REQUIRED_SYSTEM=()
+
+    echo "System toolchain status:"
+    report_required_command "git" "git"
+    report_required_command "python3" "python3"
+
+    if check_system_command "python3" && check_python_venv_support; then
+        report_component ok "python3 venv" "$(python_venv_detail)"
+    else
+        report_component failed "python3 venv" "$(python_venv_detail)"
+        MISSING_REQUIRED_SYSTEM+=("python3-venv")
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    report_required_command "ffmpeg" "ffmpeg"
+    report_required_command "ffprobe" "ffprobe"
+    report_required_command "cpulimit" "cpulimit"
+}
+
+print_python_status() {
+    echo "Repo test and docs virtualenv status:"
+
+    if check_venv_python; then
+        report_component ok "test virtualenv" "$(venv_python_detail)"
+    else
+        report_component failed "test virtualenv" "$(venv_python_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_venv_pip; then
+        report_component ok "test pip" "$(venv_pip_detail)"
+    else
+        report_component failed "test pip" "$(venv_pip_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_venv_pytest; then
+        report_component ok "test pytest" "$(venv_pytest_detail)"
+    else
+        report_component failed "test pytest" "$(venv_pytest_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_venv_sphinx; then
+        report_component ok "docs sphinx" "$(venv_sphinx_detail)"
+    else
+        report_component failed "docs sphinx" "$(venv_sphinx_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_venv_docs_packages; then
+        report_component ok "docs packages" "$(venv_docs_packages_detail)"
+    else
+        report_component failed "docs packages" "$(venv_docs_packages_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_venv_ffx; then
+        report_component ok "test ffx" "$(venv_ffx_detail)"
+    else
+        report_component failed "test ffx" "$(venv_ffx_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+
+    if check_editable_install; then
+        report_component ok "editable source" "$(editable_install_detail)"
+    else
+        report_component failed "editable source" "$(editable_install_detail)"
+        READINESS_FAILURES=$((READINESS_FAILURES + 1))
+    fi
+}
+
+print_status_report() {
+    READINESS_FAILURES=0
+
+    print_system_status
+    echo
+    print_python_status
+}
+
+detect_package_manager() {
+    if command_exists apt-get; then
+        printf 'apt-get\n'
+        return 0
+    fi
+    if command_exists pacman; then
+        printf 'pacman\n'
+        return 0
+    fi
+    return 1
+}
+
+run_root_command() {
+    if [ "${EUID}" -eq 0 ]; then
+        "$@"
+    elif command_exists sudo; then
+        sudo -n "$@"
+    else
+        return 1
+    fi
+}
+
+install_system_requirements() {
+    local package_manager
+
+    if [ "${#MISSING_REQUIRED_SYSTEM[@]}" -eq 0 ]; then
+        return 0
+    fi
+
+    if ! package_manager="$(detect_package_manager)"; then
+        printf 'No supported package manager found for automatic system preparation.\n' >&2
+        INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+        return 1
+    fi
+
+    case "${package_manager}" in
+        apt-get)
+            printf 'Installing required system dependencies via apt-get...\n'
+            if ! run_root_command apt-get update; then
+                printf 'apt-get update failed or requires interactive sudo.\n' >&2
+                INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+                return 1
+            fi
+            if ! run_root_command apt-get install -y git python3 python3-venv ffmpeg cpulimit; then
+                printf 'apt-get install failed or requires interactive sudo.\n' >&2
+                INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+                return 1
+            fi
+            ;;
+        pacman)
+            printf 'Installing required system dependencies via pacman...\n'
+            if ! run_root_command pacman -Sy --noconfirm git python ffmpeg cpulimit; then
+                printf 'pacman install failed or requires interactive sudo.\n' >&2
+                INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+                return 1
+            fi
+            ;;
+    esac
+
+    return 0
+}
+
+ensure_test_venv() {
+    if ! check_venv_python; then
+        printf 'Creating repo test virtualenv at %s...\n' "${VENV_DIR}"
+        if ! python3 -m venv "${VENV_DIR}"; then
+            printf 'Failed to create test virtualenv at %s.\n' "${VENV_DIR}" >&2
+            INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+            return 1
+        fi
+    fi
+
+    if ! check_venv_pip; then
+        printf 'Missing pip in %s.\n' "${VENV_DIR}" >&2
+        INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+        return 1
+    fi
+
+    printf 'Installing FFX package with test and docs extras into %s...\n' "${VENV_DIR}"
+    if ! (
+        cd "${ROOT_DIR}" &&
+        "${VENV_PIP}" install --editable '.[test,docs]'
+    ); then
+        printf 'Failed to install FFX package with test and docs extras into %s.\n' "${VENV_DIR}" >&2
+        INSTALL_FAILURES=$((INSTALL_FAILURES + 1))
+        return 1
+    fi
+
+    return 0
+}
+
+parse_args() {
+    while [ "$#" -gt 0 ]; do
+        case "$1" in
+            --check)
+                CHECK_ONLY=1
+                ;;
+            --help|-h)
+                usage
+                exit 0
+                ;;
+            *)
+                printf 'Unknown option: %s\n\n' "$1" >&2
+                usage >&2
+                exit 2
+                ;;
+        esac
+        shift
+    done
+}
+
+main() {
+    parse_args "$@"
+
+    print_status_report
+
+    if [ "${CHECK_ONLY}" -eq 0 ]; then
+        if [ "${#MISSING_REQUIRED_SYSTEM[@]}" -gt 0 ]; then
+            echo
+            install_system_requirements
+        fi
+
+        if check_python_environment_ready; then
+            echo
+            report_component ok "Python package install" "repo test and docs virtualenv is already ready"
+        elif check_system_command "python3" && check_python_venv_support; then
+            echo
+            ensure_test_venv
+        fi
+
+        echo
+        print_status_report
+    fi
+
+    echo
+    if [ "${INSTALL_FAILURES}" -gt 0 ]; then
+        echo "One or more test preparation steps failed; see the status checks above." >&2
+        exit 1
+    fi
+
+    if [ "${READINESS_FAILURES}" -gt 0 ]; then
+        if [ "${CHECK_ONLY}" -eq 1 ]; then
+            echo "The FFX test and docs environment is incomplete." >&2
+        else
+            echo "Required test or docs components are still missing after preparation." >&2
+        fi
+        exit 1
+    fi
+
+    if [ "${CHECK_ONLY}" -eq 1 ]; then
+        echo "The FFX test and docs environment is ready."
+    else
+        echo "The FFX test and docs environment is prepared."
+    fi
+}
+
+main "$@"

tests/unit/test_cli_subtitle_directory.py

@@ -6,7 +6,9 @@ from pathlib import Path
 import sys
 import tempfile
 import unittest
+from unittest.mock import patch
 
+import click
 from click.testing import CliRunner
 
 
@@ -17,6 +19,10 @@ if str(SRC_ROOT) not in sys.path:
 
 
 from ffx import cli  # noqa: E402
+from ffx.logging_utils import get_ffx_logger  # noqa: E402
+from ffx.media_descriptor import MediaDescriptor  # noqa: E402
+from ffx.track_descriptor import TrackDescriptor  # noqa: E402
+from ffx.track_type import TrackType  # noqa: E402
 
 
 class SubtitleDirectoryCliTests(unittest.TestCase):
@@ -48,6 +54,35 @@ class SubtitleDirectoryCliTests(unittest.TestCase):
             env={**os.environ, "HOME": str(self.home_dir)},
         )
 
+    def make_subtitle_descriptor(self, indices=(2, 3, 4)) -> MediaDescriptor:
+        return MediaDescriptor(
+            context={"logger": get_ffx_logger()},
+            track_descriptors=[
+                TrackDescriptor(
+                    index=index,
+                    source_index=index,
+                    sub_index=subIndex,
+                    track_type=TrackType.SUBTITLE,
+                )
+                for subIndex, index in enumerate(indices)
+            ],
+        )
+
+    def make_import_context(
+        self,
+        subtitleDirectory: Path,
+        noPrompt: bool,
+        yes: bool = False,
+    ) -> dict:
+        return {
+            "subtitle_match_source_basename": True,
+            "subtitle_directory": str(subtitleDirectory),
+            "subtitle_prefix": "",
+            "subtitle_extension": "vtt",
+            "no_prompt": noPrompt,
+            "yes": yes,
+        }
+
     def test_subtitle_prefix_without_directory_or_default_fails(self):
         result = self.invoke_convert("--subtitle-prefix", "dball")
 
@@ -79,6 +114,143 @@ class SubtitleDirectoryCliTests(unittest.TestCase):
 
         self.assertEqual(0, result.exit_code, result.output)
 
+    def test_explicit_directory_without_prefix_enables_basename_matching(self):
+        explicitSubtitleDirectory = self.home_dir / "manual-subtitles"
+        explicitSubtitleDirectory.mkdir(parents=True, exist_ok=True)
+
+        enabled, directory, prefix, matchBasename = cli.resolveSubtitleImportOptions(
+            {},
+            str(explicitSubtitleDirectory),
+            "",
+        )
+
+        self.assertTrue(enabled)
+        self.assertEqual(str(explicitSubtitleDirectory), directory)
+        self.assertEqual("", prefix)
+        self.assertTrue(matchBasename)
+
+    def test_subtitle_extension_accepts_optional_leading_dot(self):
+        self.assertEqual("mkv", cli.normalizeSubtitleExtension(None, None, "mkv"))
+        self.assertEqual("mkv", cli.normalizeSubtitleExtension(None, None, ".mkv"))
+
+    def test_subtitle_extension_rejects_multiple_leading_dots(self):
+        with self.assertRaises(click.BadParameter):
+            cli.normalizeSubtitleExtension(None, None, "..mkv")
+
+    def test_complete_basename_set_does_not_prompt(self):
+        subtitleDirectory = Path(__file__).resolve().parents[1] / "assets" / "subtitles"
+        descriptor = self.make_subtitle_descriptor()
+        context = self.make_import_context(subtitleDirectory, noPrompt=True)
+
+        with patch("ffx.cli.click.confirm") as mockedConfirm:
+            result = cli.importExternalSubtitles(
+                context,
+                descriptor,
+                "A2_t01",
+                -1,
+                -1,
+            )
+
+        self.assertEqual([], result["missing_track_indices"])
+        mockedConfirm.assert_not_called()
+
+    def test_incomplete_basename_set_fails_with_no_prompt(self):
+        descriptor = self.make_subtitle_descriptor()
+        subtitleDirectory = self.home_dir / "partial-subtitles"
+        subtitleDirectory.mkdir()
+        (subtitleDirectory / "episode_2_deu.vtt").write_text(
+            "WEBVTT\n\n",
+            encoding="utf-8",
+        )
+        context = self.make_import_context(subtitleDirectory, noPrompt=True)
+
+        with patch("ffx.cli.click.confirm") as mockedConfirm:
+            with self.assertRaisesRegex(click.ClickException, "--no-prompt is set"):
+                cli.importExternalSubtitles(
+                    context,
+                    descriptor,
+                    "episode",
+                    -1,
+                    -1,
+                )
+
+        mockedConfirm.assert_not_called()
+
+    def test_incomplete_basename_set_can_be_confirmed(self):
+        descriptor = self.make_subtitle_descriptor()
+        subtitleDirectory = self.home_dir / "partial-subtitles"
+        subtitleDirectory.mkdir()
+        (subtitleDirectory / "episode_2_deu.vtt").write_text(
+            "WEBVTT\n\n",
+            encoding="utf-8",
+        )
+        context = self.make_import_context(subtitleDirectory, noPrompt=False)
+
+        with patch("ffx.cli.click.confirm", return_value=True) as mockedConfirm:
+            result = cli.importExternalSubtitles(
+                context,
+                descriptor,
+                "episode",
+                -1,
+                -1,
+            )
+
+        self.assertEqual([3, 4], result["missing_track_indices"])
+        mockedConfirm.assert_called_once()
+
+    def test_incomplete_basename_set_with_yes_does_not_prompt(self):
+        descriptor = self.make_subtitle_descriptor()
+        subtitleDirectory = self.home_dir / "partial-subtitles"
+        subtitleDirectory.mkdir()
+        (subtitleDirectory / "episode_2_deu.vtt").write_text(
+            "WEBVTT\n\n",
+            encoding="utf-8",
+        )
+        context = self.make_import_context(
+            subtitleDirectory,
+            noPrompt=False,
+            yes=True,
+        )
+
+        with patch("ffx.cli.click.confirm") as mockedConfirm:
+            result = cli.importExternalSubtitles(
+                context,
+                descriptor,
+                "episode",
+                -1,
+                -1,
+            )
+
+        self.assertEqual([2], result["imported_track_indices"])
+        self.assertEqual([3, 4], result["missing_track_indices"])
+        mockedConfirm.assert_not_called()
+
+    def test_yes_takes_precedence_over_no_prompt_for_incomplete_set(self):
+        descriptor = self.make_subtitle_descriptor()
+        subtitleDirectory = self.home_dir / "partial-subtitles"
+        subtitleDirectory.mkdir()
+        (subtitleDirectory / "episode_2_deu.vtt").write_text(
+            "WEBVTT\n\n",
+            encoding="utf-8",
+        )
+        context = self.make_import_context(
+            subtitleDirectory,
+            noPrompt=True,
+            yes=True,
+        )
+
+        with patch("ffx.cli.click.confirm") as mockedConfirm:
+            result = cli.importExternalSubtitles(
+                context,
+                descriptor,
+                "episode",
+                -1,
+                -1,
+            )
+
+        self.assertEqual([3, 4], result["missing_track_indices"])
+        mockedConfirm.assert_not_called()
+
 
 if __name__ == "__main__":
     unittest.main()

tests/unit/test_cli_unmux_output_directory.py

@@ -4,6 +4,7 @@ from pathlib import Path
 import sys
 import tempfile
 import unittest
+from unittest.mock import patch
 
 import click
 
@@ -42,7 +43,7 @@ class UnmuxOutputDirectoryTests(unittest.TestCase):
         self.assertEqual(str(Path(tempdir) / "subtitles" / "dball"), resolved_output_directory)
         self.assertTrue(should_create)
 
-    def test_explicit_output_directory_keeps_existing_behavior(self):
+    def test_explicit_output_directory_requires_directory(self):
         with tempfile.TemporaryDirectory() as tempdir:
             context = {
                 "config": StaticConfig(str(Path(tempdir) / "subtitles")),
@@ -57,7 +58,7 @@ class UnmuxOutputDirectoryTests(unittest.TestCase):
             )
 
         self.assertEqual(explicit_output_directory, resolved_output_directory)
-        self.assertFalse(should_create)
+        self.assertTrue(should_create)
 
     def test_subtitles_only_without_label_keeps_existing_behavior(self):
         context = {
@@ -89,6 +90,96 @@ class UnmuxOutputDirectoryTests(unittest.TestCase):
 
         self.assertIn("subtitlesDirectory default", str(caught.exception))
 
+    def test_missing_output_directory_can_be_confirmed_and_created_with_parents(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_directory = Path(tempdir) / "missing" / "parents" / "manual"
+
+            with patch("ffx.cli.click.confirm", return_value=True) as mocked_confirm:
+                created = cli.ensureUnmuxOutputDirectory(
+                    {"dry_run": False},
+                    str(output_directory),
+                )
+
+            self.assertTrue(created)
+            self.assertTrue(output_directory.is_dir())
+            mocked_confirm.assert_called_once()
+
+    def test_tty_carriage_return_accepts_default_directory_creation(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_directory = Path(tempdir) / "missing" / "manual"
+
+            with patch("ffx.cli.sys.stdin.isatty", return_value=True), patch(
+                "ffx.cli.click.getchar",
+                return_value="\r",
+            ) as mocked_getchar, patch("ffx.cli.click.confirm") as mocked_confirm:
+                created = cli.ensureUnmuxOutputDirectory(
+                    {"dry_run": False},
+                    str(output_directory),
+                )
+
+            self.assertTrue(created)
+            self.assertTrue(output_directory.is_dir())
+            mocked_getchar.assert_called_once()
+            mocked_confirm.assert_not_called()
+
+    def test_missing_output_directory_can_be_rejected(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_directory = Path(tempdir) / "missing" / "manual"
+
+            with patch("ffx.cli.click.confirm", return_value=False) as mocked_confirm:
+                with self.assertRaises(click.ClickException) as caught:
+                    cli.ensureUnmuxOutputDirectory(
+                        {"dry_run": False},
+                        str(output_directory),
+                    )
+
+            self.assertFalse(output_directory.exists())
+            self.assertIn("aborted by user", str(caught.exception))
+            mocked_confirm.assert_called_once()
+
+    def test_existing_output_directory_does_not_prompt(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_directory = Path(tempdir) / "manual"
+            output_directory.mkdir()
+
+            with patch("ffx.cli.click.confirm") as mocked_confirm:
+                created = cli.ensureUnmuxOutputDirectory(
+                    {"dry_run": False},
+                    str(output_directory),
+                )
+
+            self.assertFalse(created)
+            mocked_confirm.assert_not_called()
+
+    def test_existing_non_directory_output_path_fails_without_prompt(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_path = Path(tempdir) / "manual"
+            output_path.write_text("not a directory", encoding="utf-8")
+
+            with patch("ffx.cli.click.confirm") as mocked_confirm:
+                with self.assertRaises(click.ClickException) as caught:
+                    cli.ensureUnmuxOutputDirectory(
+                        {"dry_run": False},
+                        str(output_path),
+                    )
+
+            self.assertIn("not a directory", str(caught.exception))
+            mocked_confirm.assert_not_called()
+
+    def test_dry_run_does_not_prompt_or_create_missing_output_directory(self):
+        with tempfile.TemporaryDirectory() as tempdir:
+            output_directory = Path(tempdir) / "missing" / "manual"
+
+            with patch("ffx.cli.click.confirm") as mocked_confirm:
+                created = cli.ensureUnmuxOutputDirectory(
+                    {"dry_run": True},
+                    str(output_directory),
+                )
+
+            self.assertFalse(created)
+            self.assertFalse(output_directory.exists())
+            mocked_confirm.assert_not_called()
+
 
 if __name__ == "__main__":
     unittest.main()

tests/unit/test_media_descriptor_import_subtitles.py

@@ -7,6 +7,7 @@ import unittest
 
 
 SRC_ROOT = Path(__file__).resolve().parents[2] / "src"
+ASSETS_ROOT = Path(__file__).resolve().parents[1] / "assets"
 
 if str(SRC_ROOT) not in sys.path:
     sys.path.insert(0, str(SRC_ROOT))
@@ -20,18 +21,19 @@ from ffx.track_type import TrackType  # noqa: E402
 
 
 class MediaDescriptorImportSubtitlesTests(unittest.TestCase):
-    def make_descriptor(self) -> MediaDescriptor:
+    def make_descriptor(self, indices=(3,)) -> MediaDescriptor:
         return MediaDescriptor(
             context={"logger": get_ffx_logger()},
             track_descriptors=[
                 TrackDescriptor(
-                    index=3,
-                    source_index=3,
-                    sub_index=0,
+                    index=index,
+                    source_index=index,
+                    sub_index=subIndex,
                     track_type=TrackType.SUBTITLE,
                     tags={"language": "eng", "title": "DB Subtitle"},
                     disposition_set={TrackDisposition.DEFAULT},
                 )
+                for subIndex, index in enumerate(indices)
             ],
         )
 
@@ -74,6 +76,110 @@ class MediaDescriptorImportSubtitlesTests(unittest.TestCase):
         self.assertEqual("deu", track.getTags()["language"])
         self.assertEqual({TrackDisposition.FORCED}, track.getDispositionSet())
 
+    def test_strict_basename_import_recognizes_vtt_asset_set(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        result = descriptor.importSubtitles(
+            str(ASSETS_ROOT / "subtitles"),
+            "A2_t01",
+            strict=True,
+        )
+
+        self.assertEqual(3, result["candidate_count"])
+        self.assertEqual([2, 3, 4], result["imported_track_indices"])
+        self.assertEqual([], result["missing_track_indices"])
+        self.assertEqual(
+            [
+                "A2_t01_2_deu_DEF.vtt",
+                "A2_t01_3_eng.vtt",
+                "A2_t01_4_eng.vtt",
+            ],
+            [
+                Path(track.getExternalSourceFilePath()).name
+                for track in descriptor.getSubtitleTracks()
+            ],
+        )
+
+    def test_strict_basename_import_accepts_dotted_mkv_extension(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        result = descriptor.importSubtitles(
+            str(ASSETS_ROOT / "subtitles"),
+            "A2_t01",
+            extension=".mkv",
+            strict=True,
+        )
+
+        self.assertEqual(3, result["candidate_count"])
+        self.assertEqual([2, 3, 4], result["imported_track_indices"])
+        self.assertEqual([], result["missing_track_indices"])
+        self.assertTrue(
+            all(
+                track.getExternalSourceFilePath().endswith(".mkv")
+                for track in descriptor.getSubtitleTracks()
+            )
+        )
+
+    def test_strict_basename_import_reports_missing_tracks(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            sidecarPath = Path(tmpdir) / "episode_2_deu.vtt"
+            sidecarPath.write_text("WEBVTT\n\n", encoding="utf-8")
+
+            result = descriptor.importSubtitles(
+                tmpdir,
+                "episode",
+                strict=True,
+            )
+
+        self.assertEqual([2], result["imported_track_indices"])
+        self.assertEqual([3, 4], result["missing_track_indices"])
+
+    def test_strict_basename_import_rejects_too_many_files(self):
+        descriptor = self.make_descriptor(indices=(2,))
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            for filename in ("episode_2_deu.vtt", "episode_3_eng.vtt"):
+                (Path(tmpdir) / filename).write_text("WEBVTT\n\n", encoding="utf-8")
+
+            with self.assertRaisesRegex(ValueError, "2 matching .* for 1 subtitle tracks"):
+                descriptor.importSubtitles(tmpdir, "episode", strict=True)
+
+    def test_strict_basename_import_rejects_unknown_track_index(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            (Path(tmpdir) / "episode_9_eng.vtt").write_text(
+                "WEBVTT\n\n",
+                encoding="utf-8",
+            )
+
+            with self.assertRaisesRegex(ValueError, "track index pattern does not match"):
+                descriptor.importSubtitles(tmpdir, "episode", strict=True)
+
+    def test_strict_basename_import_rejects_malformed_filtered_filename(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            (Path(tmpdir) / "episode_s01e01_2_deu.vtt").write_text(
+                "WEBVTT\n\n",
+                encoding="utf-8",
+            )
+
+            with self.assertRaisesRegex(ValueError, "expected pattern"):
+                descriptor.importSubtitles(tmpdir, "episode", strict=True)
+
+    def test_strict_basename_import_rejects_duplicate_track_indices(self):
+        descriptor = self.make_descriptor(indices=(2, 3, 4))
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            for filename in ("episode_2_deu.vtt", "episode_2_eng.vtt"):
+                (Path(tmpdir) / filename).write_text("WEBVTT\n\n", encoding="utf-8")
+
+            with self.assertRaisesRegex(ValueError, "Multiple external subtitle files"):
+                descriptor.importSubtitles(tmpdir, "episode", strict=True)
+
 
 if __name__ == "__main__":
     unittest.main()