diff --git a/README.md b/README.md
index 428eb9f47..1d6a4a86d 100644
--- a/README.md
+++ b/README.md
@@ -999,12 +999,16 @@ If you fork the project on GitHub, you can run your fork's [build workflow](.git
                                     be used multiple times
     --no-exec                       Remove any previously defined --exec
     --convert-subs FORMAT           Convert the subtitles to another format
-                                    (currently supported: ass, lrc, srt, vtt)
-                                    (Alias: --convert-subtitles)
+                                    (currently supported: ass, lrc, srt, vtt).
+                                    Use "--convert-subs none" to disable
+                                    conversion (default) (Alias: --convert-
+                                    subtitles)
     --convert-thumbnails FORMAT     Convert the thumbnails to another format
                                     (currently supported: jpg, png, webp). You
                                     can specify multiple rules using similar
-                                    syntax as --remux-video
+                                    syntax as "--remux-video". Use "--convert-
+                                    thumbnails none" to disable conversion
+                                    (default)
     --split-chapters                Split video into multiple files based on
                                     internal chapters. The "chapter:" prefix can
                                     be used with "--paths" and "--output" to set
diff --git a/yt_dlp/__init__.py b/yt_dlp/__init__.py
index c0b8e3b50..c2d19f94a 100644
--- a/yt_dlp/__init__.py
+++ b/yt_dlp/__init__.py
@@ -235,6 +235,11 @@ def validate_options(opts):
         validate_regex('format sorting', f, FormatSorter.regex)
 
     # Postprocessor formats
+    if opts.convertsubtitles == 'none':
+        opts.convertsubtitles = None
+    if opts.convertthumbnails == 'none':
+        opts.convertthumbnails = None
+
     validate_regex('merge output format', opts.merge_output_format,
                    r'({0})(/({0}))*'.format('|'.join(map(re.escape, FFmpegMergerPP.SUPPORTED_EXTS))))
     validate_regex('audio format', opts.audioformat, FFmpegExtractAudioPP.FORMAT_RE)
diff --git a/yt_dlp/options.py b/yt_dlp/options.py
index ffe2463fe..8077d5d88 100644
--- a/yt_dlp/options.py
+++ b/yt_dlp/options.py
@@ -1725,15 +1725,17 @@ def create_parser():
         '--convert-subs', '--convert-sub', '--convert-subtitles',
         metavar='FORMAT', dest='convertsubtitles', default=None,
         help=(
-            'Convert the subtitles to another format (currently supported: {}) '
-            '(Alias: --convert-subtitles)'.format(', '.join(sorted(FFmpegSubtitlesConvertorPP.SUPPORTED_EXTS)))))
+            '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'))
+            '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,