Extd cut parameter

src/ffx/cli.py

@@ -17,6 +17,8 @@ from ffx.constants import (
     DEFAULT_AC3_BANDWIDTH,
     DEFAULT_CROPDETECT_DURATION_SECONDS,
     DEFAULT_CROPDETECT_SEEK_SECONDS,
+    DEFAULT_cut_length,
+    DEFAULT_cut_start,
     DEFAULT_CONTAINER_EXTENSION,
     DEFAULT_CONTAINER_FORMAT,
     DEFAULT_DTS_BANDWIDTH,
@@ -45,6 +47,14 @@ CROPDETECT_DURATION_OPTION_HELP = (
     "Analyze this many seconds for crop detection. "
     + "Shorter windows are faster; longer windows are usually steadier."
 )
+DEFAULT_CUT_OPTION_VALUE = f"{DEFAULT_cut_start},{DEFAULT_cut_length}"
+CUT_OPTION_HELP = (
+    "Cut output in seconds. "
+    + f"Use --cut for the default {DEFAULT_CUT_OPTION_VALUE}, "
+    + "--cut DURATION to cut from 0 for DURATION seconds, "
+    + "or --cut START,DURATION for an explicit start and duration. "
+    + "Omit to disable."
+)
 
 
 def normalizeNicenessOption(ctx, param, value):
@@ -65,6 +75,48 @@ def normalizeCpuOption(ctx, param, value):
         raise click.BadParameter(str(ex)) from ex
 
 
+def parseCutOptionValue(value) -> tuple[int, int] | None:
+    if value is None:
+        return None
+
+    cutValue = str(value).strip()
+    if not cutValue:
+        raise ValueError(
+            "Cut value must be DURATION or START,DURATION, or use --cut without a value."
+        )
+
+    cutTokens = [token.strip() for token in cutValue.split(',')]
+
+    try:
+        if len(cutTokens) == 1:
+            cutStart = 0
+            cutLength = int(cutTokens[0])
+        elif len(cutTokens) == 2:
+            cutStart = int(cutTokens[0])
+            cutLength = int(cutTokens[1])
+        else:
+            raise ValueError
+    except ValueError as ex:
+        raise ValueError(
+            "Cut value must be DURATION or START,DURATION, or use --cut without a value."
+        ) from ex
+
+    if cutStart < 0:
+        raise ValueError("Cut start must be 0 or greater.")
+
+    if cutLength <= 0:
+        raise ValueError("Cut duration must be greater than 0.")
+
+    return cutStart, cutLength
+
+
+def normalizeCutOption(ctx, param, value):
+    try:
+        return parseCutOptionValue(value)
+    except ValueError as ex:
+        raise click.BadParameter(str(ex)) from ex
+
+
 
 @click.group()
 @click.pass_context
@@ -582,7 +634,16 @@ def checkUniqueDispositions(context, mediaDescriptor: MediaDescriptor):
     show_default=True,
     help='When --crop auto is used, analyze this many seconds for crop detection.',
 )
-@click.option("--cut", is_flag=False, flag_value="default", default="none")
+@click.option(
+    "--cut",
+    type=str,
+    metavar="DURATION|START,DURATION",
+    is_flag=False,
+    flag_value=DEFAULT_CUT_OPTION_VALUE,
+    default=None,
+    callback=normalizeCutOption,
+    help=CUT_OPTION_HELP,
+)
 
 @click.option("--output-directory", type=str, default='')
 
@@ -823,13 +884,15 @@ def convert(ctx,
 
     #->
     # Process cut parameters
-    context['perform_cut'] = (cut != 'none')
+    context['perform_cut'] = (cut is not None)
     if context['perform_cut']:
-        cutTokens = cut.split(',')
-        if cutTokens and len(cutTokens) == 2:
-            context['cut_start'] = int(cutTokens[0])
-            context['cut_length'] = int(cutTokens[1])
-            ctx.obj['logger'].debug(f"Cut start={context['cut_start']} length={context['cut_length']}")
+        context['cut_start'], context['cut_length'] = cut
+        click.echo(
+            f"Cutting enabled: start {context['cut_start']} s, duration {context['cut_length']} s."
+        )
+        ctx.obj['logger'].debug(
+            f"Cut start={context['cut_start']} length={context['cut_length']}"
+        )
 
 
     tc = TmdbController() if context['use_tmdb'] else None