[PostProcessing] Crop mp3 thumbnails

youtube_dl/__init__.py

@@ -287,7 +287,8 @@ def _real_main(argv=None):
         already_have_thumbnail = opts.writethumbnail or opts.write_all_thumbnails
         postprocessors.append({
             'key': 'EmbedThumbnail',
-            'already_have_thumbnail': already_have_thumbnail
+            'already_have_thumbnail': already_have_thumbnail,
+            'crop_thumbnail': opts.cropthumbnail,
         })
         if not already_have_thumbnail:
             opts.writethumbnail = True

youtube_dl/options.py

@@ -814,6 +814,10 @@ def parseOpts(overrideArguments=None):
         '--embed-thumbnail',
         action='store_true', dest='embedthumbnail', default=False,
         help='Embed thumbnail in the audio as cover art')
+    postproc.add_option(
+        '--crop-thumbnail',
+        action='store_true', dest='cropthumbnail', default=False,
+        help='Crop the thumbnail to an square; No effect without --embed-thumbnail')
     postproc.add_option(
         '--add-metadata',
         action='store_true', dest='addmetadata', default=False,

youtube_dl/postprocessor/embedthumbnail.py

@@ -22,9 +22,10 @@ class EmbedThumbnailPPError(PostProcessingError):
 
 
 class EmbedThumbnailPP(FFmpegPostProcessor):
-    def __init__(self, downloader=None, already_have_thumbnail=False):
+    def __init__(self, downloader=None, already_have_thumbnail=False, crop_thumbnail=False):
         super(EmbedThumbnailPP, self).__init__(downloader)
         self._already_have_thumbnail = already_have_thumbnail
+        self._crop_thumbnail = crop_thumbnail
 
     def run(self, info):
         filename = info['filepath']
@@ -42,8 +43,17 @@ class EmbedThumbnailPP(FFmpegPostProcessor):
             return [], info
 
         if info['ext'] == 'mp3':
-            options = [
-                '-c', 'copy', '-map', '0', '-map', '1',
+            options = []
+            if self._crop_thumbnail:
+                options.append(
+                    '-c:a', 'copy', '-c:v', 'mjpeg',  # Copy audio stream, re-encode resulting thumb
+                    '-vf', 'crop="\'if(gt(ih,iw),iw,ih)\':\'if(gt(iw,ih),ih,iw)\'"'  # Use the crop filter on the image
+                )
+            else:
+                options.append('-c', 'copy')  # Copy both streams instead
+
+            options += [
+                '-map', '0', '-map', '1',
                 '-metadata:s:v', 'title="Album cover"', '-metadata:s:v', 'comment="Cover (Front)"']
 
             self._downloader.to_screen('[ffmpeg] Adding thumbnail to "%s"' % filename)