restructured manifest and plugins loading; updated plugins

plugins/youtube_download/yt_dlp/downloader/external.py

@@ -563,7 +563,7 @@ class FFmpegFD(ExternalFD):
                     f'{cookie.name}={cookie.value}; path={cookie.path}; domain={cookie.domain};\r\n'
                     for cookie in cookies)])
             if fmt.get('http_headers') and is_http:
-                # Trailing \r\n after each HTTP header is important to prevent warning from ffmpeg/avconv:
+                # Trailing \r\n after each HTTP header is important to prevent warning from ffmpeg:
                 # [http @ 00000000003d2fa0] No trailing CRLF found in HTTP header.
                 args.extend(['-headers', ''.join(f'{key}: {val}\r\n' for key, val in fmt['http_headers'].items())])
 
@@ -572,7 +572,21 @@ class FFmpegFD(ExternalFD):
             if end_time:
                 args += ['-t', str(end_time - start_time)]
 
-            args += [*self._configuration_args((f'_i{i + 1}', '_i')), '-i', fmt['url']]
+            url = fmt['url']
+            if self.params.get('enable_file_urls') and url.startswith('file:'):
+                # The default protocol_whitelist is 'file,crypto,data' when reading local m3u8 URLs,
+                # so only local segments can be read unless we also include 'http,https,tcp,tls'
+                args += ['-protocol_whitelist', 'file,crypto,data,http,https,tcp,tls']
+                # ffmpeg incorrectly handles 'file:' URLs by only removing the
+                # 'file:' prefix and treating the rest as if it's a normal filepath.
+                # FFmpegPostProcessor also depends on this behavior, so we need to fixup the URLs:
+                # - On Windows/Cygwin, replace 'file:///' and 'file://localhost/' with 'file:'
+                # - On *nix, replace 'file://localhost/' with 'file:/'
+                # Ref: https://github.com/yt-dlp/yt-dlp/issues/13781
+                #      https://trac.ffmpeg.org/ticket/2702
+                url = re.sub(r'^file://(?:localhost)?/', 'file:' if os.name == 'nt' else 'file:/', url)
+
+            args += [*self._configuration_args((f'_i{i + 1}', '_i')), '-i', url]
 
         if not (start_time or end_time) or not self.params.get('force_keyframes_at_cuts'):
             args += ['-c', 'copy']
@@ -640,10 +654,6 @@ class FFmpegFD(ExternalFD):
             return retval
 
 
-class AVconvFD(FFmpegFD):
-    pass
-
-
 _BY_NAME = {
     klass.get_basename(): klass
     for name, klass in globals().items()