No longer enable --mtime by default

README.md

@@ -1128,15 +1128,15 @@ # CONFIGURATION
     * `/etc/yt-dlp/config`
     * `/etc/yt-dlp/config.txt`
 
-E.g. with the following configuration file, yt-dlp will always extract the audio, not copy the mtime, use a proxy and save all videos under `YouTube` directory in your home directory:
+E.g. with the following configuration file, yt-dlp will always extract the audio, copy the mtime, use a proxy and save all videos under `YouTube` directory in your home directory:
 ```
 # Lines starting with # are comments
 
 # Always extract audio
 -x
 
-# Do not copy the mtime
---no-mtime
+# Copy the mtime
+--mtime
 
 # Use this proxy
 --proxy 127.0.0.1:3128
@@ -2231,6 +2231,7 @@ ### Differences in default behavior
 * yt-dlp uses modern http client backends such as `requests`. Use `--compat-options prefer-legacy-http-handler` to prefer the legacy http handler (`urllib`) to be used for standard http requests.
 * The sub-modules `swfinterp`, `casefold` are removed.
 * Passing `--simulate` (or calling `extract_info` with `download=False`) no longer alters the default format selection. See [#9843](https://github.com/yt-dlp/yt-dlp/issues/9843) for details.
+* yt-dlp no longer sets `mtime` for files by default. Use `--mtime` or `--compat-options mtime-by-default` to revert this.
 
 For ease of use, a few more compat options are available:
 
@@ -2239,7 +2240,8 @@ ### Differences in default behavior
 * `--compat-options youtube-dlc`: Same as `--compat-options all,-no-live-chat,-no-youtube-channel-redirect,-playlist-match-filter,-manifest-filesize-approx,-allow-unsafe-ext,-prefer-vp9-sort`
 * `--compat-options 2021`: Same as `--compat-options 2022,no-certifi,filename-sanitization,no-youtube-prefer-utc-upload-date`
 * `--compat-options 2022`: Same as `--compat-options 2023,playlist-match-filter,no-external-downloader-progress,prefer-legacy-http-handler,manifest-filesize-approx`
-* `--compat-options 2023`: Same as `--compat-options prefer-vp9-sort`. Use this to enable all future compat options
+* `--compat-options 2023`: Same as `--compat-options 2024,prefer-vp9-sort`
+* `--compat-options 2024`: Same as `--compat-options mtime-by-default`. Use this to enable all future compat options
 
 The following compat options restore vulnerable behavior from before security patches:
 

yt_dlp/YoutubeDL.py

@@ -482,7 +482,8 @@ class YoutubeDL:
                        The following options do not work when used through the API:
                        filename, abort-on-error, multistreams, no-live-chat,
                        format-sort, no-clean-infojson, no-playlist-metafiles,
-                       no-keep-subs, no-attach-info-json, allow-unsafe-ext, prefer-vp9-sort.
+                       no-keep-subs, no-attach-info-json, allow-unsafe-ext, prefer-vp9-sort,
+                       mtime-by-default.
                        Refer __init__.py for their implementation
     progress_template: Dictionary of templates for progress outputs.
                        Allowed keys are 'download', 'postprocess',

yt_dlp/__init__.py

@@ -159,6 +159,12 @@ def set_default_compat(compat_name, opt_name, default=True, remove_compat=True):
     elif 'prefer-vp9-sort' in opts.compat_opts:
         opts.format_sort.extend(FormatSorter._prefer_vp9_sort)
 
+    if 'mtime-by-default' in opts.compat_opts:
+        if opts.updatetime is None:
+            opts.updatetime = True
+        else:
+            _unused_compat_opt('mtime-by-default')
+
     _video_multistreams_set = set_default_compat('multistreams', 'allow_multiple_video_streams', False, remove_compat=False)
     _audio_multistreams_set = set_default_compat('multistreams', 'allow_multiple_audio_streams', False, remove_compat=False)
     if _video_multistreams_set is False and _audio_multistreams_set is False:

yt_dlp/downloader/fragment.py

@@ -302,7 +302,7 @@ def _finish_frag_download(self, ctx, info_dict):
         elif to_file:
             self.try_rename(ctx['tmpfilename'], ctx['filename'])
             filetime = ctx.get('fragment_filetime')
-            if self.params.get('updatetime', True) and filetime:
+            if self.params.get('updatetime') and filetime:
                 with contextlib.suppress(Exception):
                     os.utime(ctx['filename'], (time.time(), filetime))
 

yt_dlp/downloader/http.py

@@ -348,7 +348,7 @@ def retry(e):
             self.try_rename(ctx.tmpfilename, ctx.filename)
 
             # Update file modification time
-            if self.params.get('updatetime', True):
+            if self.params.get('updatetime'):
                 info_dict['filetime'] = self.try_utime(ctx.filename, ctx.data.headers.get('last-modified', None))
 
             self._hook_progress({

yt_dlp/options.py

@@ -494,13 +494,14 @@ def _alias_callback(option, opt_str, value, parser, opts, nargs):
                 'no-attach-info-json', 'embed-thumbnail-atomicparsley', 'no-external-downloader-progress',
                 'embed-metadata', 'seperate-video-versions', 'no-clean-infojson', 'no-keep-subs', 'no-certifi',
                 'no-youtube-channel-redirect', 'no-youtube-unavailable-videos', 'no-youtube-prefer-utc-upload-date',
-                'prefer-legacy-http-handler', 'manifest-filesize-approx', 'allow-unsafe-ext', 'prefer-vp9-sort',
+                'prefer-legacy-http-handler', 'manifest-filesize-approx', 'allow-unsafe-ext', 'prefer-vp9-sort', 'mtime-by-default',
             }, 'aliases': {
                 'youtube-dl': ['all', '-multistreams', '-playlist-match-filter', '-manifest-filesize-approx', '-allow-unsafe-ext', '-prefer-vp9-sort'],
                 'youtube-dlc': ['all', '-no-youtube-channel-redirect', '-no-live-chat', '-playlist-match-filter', '-manifest-filesize-approx', '-allow-unsafe-ext', '-prefer-vp9-sort'],
                 '2021': ['2022', 'no-certifi', 'filename-sanitization'],
                 '2022': ['2023', 'no-external-downloader-progress', 'playlist-match-filter', 'prefer-legacy-http-handler', 'manifest-filesize-approx'],
-                '2023': ['prefer-vp9-sort'],
+                '2023': ['2024', 'prefer-vp9-sort'],
+                '2024': ['mtime-by-default'],
             },
         }, help=(
             'Options that can help keep compatibility with youtube-dl or youtube-dlc '
@@ -1421,7 +1422,7 @@ def _alias_callback(option, opt_str, value, parser, opts, nargs):
         help='Do not use .part files - write directly into output file')
     filesystem.add_option(
         '--mtime',
-        action='store_true', dest='updatetime', default=True,
+        action='store_true', dest='updatetime', default=None,
         help='Use the Last-modified header to set the file modification time (default)')
     filesystem.add_option(
         '--no-mtime',