From 1c12d62797f8023ae6314499e8873b9bfe479e90 Mon Sep 17 00:00:00 2001
From: Brendan Brewster <brendan.brewster@gmail.com>
Date: Thu, 14 Dec 2017 19:08:13 -0500
Subject: [PATCH] ffmpeg postprocessor use playlist_index for track metadata
 when track_number does not set

---
 youtube_dl/postprocessor/ffmpeg.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index 3ea1afcf3..1c15fccfe 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -419,6 +419,8 @@ class FFmpegMetadataPP(FFmpegPostProcessor):
         add(('description', 'comment'), 'description')
         add('purl', 'webpage_url')
         add('track', 'track_number')
+        if metadata.get('track') is None:
+            add('track', 'playlist_index')
         add('artist', ('artist', 'creator', 'uploader', 'uploader_id'))
         add('genre')
         add('album')