diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index fd3f921a8..e0a428a82 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -451,7 +451,7 @@ class FFmpegMetadataPP(FFmpegPostProcessor):
         add('date', 'upload_date')
         add(('description', 'comment'), 'description')
         add('purl', 'webpage_url')
-        add('track', 'track_number')
+        add('track', ('track_number', 'playlist_index'))
         add('artist', ('artist', 'creator', 'uploader', 'uploader_id'))
         add('genre')
         add('album')