Repository: yt-dlp/yt-dlp
File: yt_dlp/options.py (Python)

Code before:
    postproc.add_option(
        '--no-exec',
        action='store_const', dest='exec_cmd', const={},
        help='Remove any previously defined --exec')
    postproc.add_option(
        '--exec-before-download', metavar='CMD',
        action='append', dest='exec_before_dl_cmd',
        help=optparse.SUPPRESS_HELP)
    postproc.add_option(
        '--no-exec-before-download',
        action='store_const', dest='exec_before_dl_cmd', const=None,
        help=optparse.SUPPRESS_HELP)
    postproc.add_option(
        '--convert-subs', '--convert-sub', '--convert-subtitles',
        metavar='FORMAT', dest='convertsubtitles', default=None,
        help=(
            'Convert the subtitles to another format '
            f'(currently supported: {", ".join(sorted(FFmpegSubtitlesConvertorPP.SUPPORTED_EXTS))}, none) '
            '(Alias: --convert-subtitles)'))
    postproc.add_option(
        '--convert-thumbnails',
        metavar='FORMAT', dest='convertthumbnails', default=None,
        help=(
            'Convert the thumbnails to another format '
            f'(currently supported: {", ".join(sorted(FFmpegThumbnailsConvertorPP.SUPPORTED_EXTS))}, none). '
            'You can specify multiple rules using similar syntax as --remux-video'))
    postproc.add_option(
        '--split-chapters', '--split-tracks',
        dest='split_chapters', action='store_true', default=False,
        help=(
            'Split video into multiple files based on internal chapters. '
            'The "chapter:" prefix can be used with "--paths" and "--output" to '
            'set the output filename for the split files. See "OUTPUT TEMPLATE" for details'))
    postproc.add_option(
        '--no-split-chapters', '--no-split-tracks',
        dest='split_chapters', action='store_false',
        help='Do not split video based on chapters (default)')
    postproc.add_option(
        '--remove-chapters',
        metavar='REGEX', dest='remove_chapters', action='append',
        help=(
            'Remove chapters whose title matches the given regular expression. '
            'The syntax is the same as --download-sections. This option can be used multiple times'))
    postproc.add_option(
        '--no-remove-chapters', dest='remove_chapters', action='store_const', const=None,
        help='Do not remove any chapters from the file (default)')
    postproc.add_option(
        '--force-keyframes-at-cuts',
        action='store_true', dest='force_keyframes_at_cuts', default=False,
        help=(
            'Force keyframes at cuts when downloading/splitting/removing sections. '

Review comment (suggestion):
tacking `none` on to the end of the extension list is misleading here IMO, since the following line then implies you can use it like `--convert-thumb "jpg>png/webp>none"`
```suggestion
            f'(currently supported: {", ".join(sorted(FFmpegThumbnailsConvertorPP.SUPPORTED_EXTS))}). '
            'You can specify multiple rules using similar syntax as "--remux-video". '
            'A previous pass of this option can be negated with "--convert-thumbnails none"'))
```

Code after:
    postproc.add_option(
        '--no-exec',
        action='store_const', dest='exec_cmd', const={},
        help='Remove any previously defined --exec')
    postproc.add_option(
        '--exec-before-download', metavar='CMD',
        action='append', dest='exec_before_dl_cmd',
        help=optparse.SUPPRESS_HELP)
    postproc.add_option(
        '--no-exec-before-download',
        action='store_const', dest='exec_before_dl_cmd', const=None,
        help=optparse.SUPPRESS_HELP)
    postproc.add_option(
        '--convert-subs', '--convert-sub', '--convert-subtitles',
        metavar='FORMAT', dest='convertsubtitles', default=None,
        help=(
            'Convert the subtitles to another format '
            f'(currently supported: {", ".join(sorted(FFmpegSubtitlesConvertorPP.SUPPORTED_EXTS))}). '
            'Use "--convert-subs none" to disable conversion (default) (Alias: --convert-subtitles)'))
    postproc.add_option(
        '--convert-thumbnails',
        metavar='FORMAT', dest='convertthumbnails', default=None,
        help=(
            'Convert the thumbnails to another format '
            f'(currently supported: {", ".join(sorted(FFmpegThumbnailsConvertorPP.SUPPORTED_EXTS))}). '
            'You can specify multiple rules using similar syntax as "--remux-video". '
            'Use "--convert-thumbnails none" to disable conversion (default)'))
    postproc.add_option(
        '--split-chapters', '--split-tracks',
        dest='split_chapters', action='store_true', default=False,
        help=(
            'Split video into multiple files based on internal chapters. '
            'The "chapter:" prefix can be used with "--paths" and "--output" to '
            'set the output filename for the split files. See "OUTPUT TEMPLATE" for details'))
    postproc.add_option(
        '--no-split-chapters', '--no-split-tracks',
        dest='split_chapters', action='store_false',
        help='Do not split video based on chapters (default)')
    postproc.add_option(
        '--remove-chapters',
        metavar='REGEX', dest='remove_chapters', action='append',
        help=(
            'Remove chapters whose title matches the given regular expression. '
            'The syntax is the same as --download-sections. This option can be used multiple times'))
    postproc.add_option(
        '--no-remove-chapters', dest='remove_chapters', action='store_const', const=None,
        help='Do not remove any chapters from the file (default)')
    postproc.add_option(
        '--force-keyframes-at-cuts',
        action='store_true', dest='force_keyframes_at_cuts', default=False,
        help=(