--embed-subs fails when used along with --add-metadata on mp4 container

[dstftw]

What is the purpose of your issue?

• Bug report (encountered problems with youtube-dl)

---

> py -3.6 .\youtube_dl\__main__.py -v KaAdS8Oso9U -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best' --embed-subs --all-subs  -k --add-metadata
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', 'KaAdS8Oso9U', '-f', 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best', '--embed-subs', '--all-subs', '-k', '--add-metadata']
[debug] Encodings: locale cp1251, fs utf-8, out utf-8, pref cp1251
[debug] youtube-dl version 2019.01.27
[debug] Git HEAD: e71be6e
[debug] Python version 3.6.4 (CPython) - Windows-10-10.0.10240-SP0
[debug] exe versions: ffmpeg N-85653-gb4330a0, ffprobe N-85653-gb4330a0, phantomjs 2.1.1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] KaAdS8Oso9U: Downloading webpage
[youtube] KaAdS8Oso9U: Downloading video info webpage
[info] Writing video subtitles to: Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.en.vtt
[debug] Invoking downloader on '<snip>'
[download] Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.f137.mp4 has already been downloaded
[download] 100% of 43.74MiB
[debug] Invoking downloader on '<snip>'
[download] Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.f140.m4a has already been downloaded
[download] 100% of 4.23MiB
[ffmpeg] Merging formats into "Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4"
[debug] ffmpeg command line: ffmpeg -y -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.f137.mp4" -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.f140.m4a" -c copy -map "0:v:0" -map "1:a:0" "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.temp.mp4"
[ffmpeg] Adding metadata to 'Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4'
[debug] ffmpeg command line: ffmpeg -y -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4" -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.meta" -c copy -metadata "title=Awkward Megyn Kelly Interviews That Will Make You Cringe" -metadata "date=20171219" -metadata "description=If you're new, Subscribe! → http://bit.ly/Subscribe-to-Nicki-Swift

Megyn Kelly didn't have the 2017 she likely thought she would. After leaving Fox News to headline her own morning talk show for NBC, Megyn Kelly Today, the former anchor has been repeatedly slammed by audiences and critics for her many awkward gaffes. Here's a look at some awkward Megyn Kelly interviews that will make you cringe...

The cast of Will and Grace | 0:20
Jane Fonda | 1:02
The Menendez Brothers | 1:43
Suzanne Somers | 2:14
Carli Lloyd | 2:53
Russell Brand | 3:32

Read more here → http://www.nickiswift.com/97614/uncomfortable-megyn-kelly-interviews-ever/

On-Set Drama
https://www.youtube.com/playlist?list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Celebrities Who Allegedly Gave Their Co-Stars the Creeps
https://www.youtube.com/watch?v=LbJ_JipBako&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

The Untold Truth Of Savannah Guthrie
https://www.youtube.com/watch?v=aB5KiiRKilY&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

TV Show Hosts Who Treat Their Staff Like Garbage
https://www.youtube.com/watch?v=joco3n_A-Oo&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Celebrity Chefs Who Completely Lost It On Camera
https://www.youtube.com/watch?v=wb4Rz1OoWsI&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Kevin James Explains The Real Reason Why He Killed Off His TV Wife
https://www.youtube.com/watch?v=Qa6uihTp6Ds&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

The Shady Side Of Kelly Ripa
https://www.youtube.com/watch?v=HVlJKTObpPc&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Website → http://www.nickiswift.com/
Like us → https://www.facebook.com/NickiSwiftCeleb/
Instagram → https://www.instagram.com/NickiSwiftCeleb/
Pinterest → https://www.pinterest.com/NickiSwiftCeleb/

Plenty of entertainment brands tackle Hollywood, but Nicki Swift stands apart in style and smarts. Spending time with us is like hanging out with friends who keeps the conversation clever, quick, and classy. We dish out the good stuff on all your favorite celebs, add expert analysis, then move on to the next hot topic, all without breaking a sweat." -metadata "comment=If you're new, Subscribe! → http://bit.ly/Subscribe-to-Nicki-Swift

Megyn Kelly didn't have the 2017 she likely thought she would. After leaving Fox News to headline her own morning talk show for NBC, Megyn Kelly Today, the former anchor has been repeatedly slammed by audiences and critics for her many awkward gaffes. Here's a look at some awkward Megyn Kelly interviews that will make you cringe...

The cast of Will and Grace | 0:20
Jane Fonda | 1:02
The Menendez Brothers | 1:43
Suzanne Somers | 2:14
Carli Lloyd | 2:53
Russell Brand | 3:32

Read more here → http://www.nickiswift.com/97614/uncomfortable-megyn-kelly-interviews-ever/

On-Set Drama
https://www.youtube.com/playlist?list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Celebrities Who Allegedly Gave Their Co-Stars the Creeps
https://www.youtube.com/watch?v=LbJ_JipBako&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

The Untold Truth Of Savannah Guthrie
https://www.youtube.com/watch?v=aB5KiiRKilY&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

TV Show Hosts Who Treat Their Staff Like Garbage
https://www.youtube.com/watch?v=joco3n_A-Oo&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Celebrity Chefs Who Completely Lost It On Camera
https://www.youtube.com/watch?v=wb4Rz1OoWsI&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Kevin James Explains The Real Reason Why He Killed Off His TV Wife
https://www.youtube.com/watch?v=Qa6uihTp6Ds&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

The Shady Side Of Kelly Ripa
https://www.youtube.com/watch?v=HVlJKTObpPc&list=PLdEKZTDH6MLFxmbDH_G9E_iUr8i-4Civb

Website → http://www.nickiswift.com/
Like us → https://www.facebook.com/NickiSwiftCeleb/
Instagram → https://www.instagram.com/NickiSwiftCeleb/
Pinterest → https://www.pinterest.com/NickiSwiftCeleb/

Plenty of entertainment brands tackle Hollywood, but Nicki Swift stands apart in style and smarts. Spending time with us is like hanging out with friends who keeps the conversation clever, quick, and classy. We dish out the good stuff on all your favorite celebs, add expert analysis, then move on to the next hot topic, all without breaking a sweat." -metadata "purl=https://www.youtube.com/watch?v=KaAdS8Oso9U" -metadata "artist=Nicki Swift" -map_metadata 1 "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.temp.mp4"
[ffmpeg] Embedding subtitles in 'Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4'
[debug] ffmpeg command line: ffmpeg -y -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4" -i "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.en.vtt" -map 0 -c copy -map "-0:s" "-c:s" mov_text -map "1:0" "-metadata:s:s:0" "language=eng" "file:Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.temp.mp4"
ERROR:     Last message repeated 1 times
Traceback (most recent call last):
  File "C:\Dev\youtube-dl\master\youtube_dl\YoutubeDL.py", line 2051, in post_process
    files_to_delete, info = pp.run(info)
  File "C:\Dev\youtube-dl\master\youtube_dl\postprocessor\ffmpeg.py", line 420, in run
    self.run_ffmpeg_multiple_files(input_files, temp_filename, opts)
  File "C:\Dev\youtube-dl\master\youtube_dl\postprocessor\ffmpeg.py", line 232, in run_ffmpeg_multiple_files
    raise FFmpegPostProcessorError(msg)
youtube_dl.postprocessor.ffmpeg.FFmpegPostProcessorError:     Last message repeated 1 times

---

Description of your issue, suggested solution and other information

--add-metadata happens first leaving Apple chapters track in resulting mp4 file:

> ffmpeg.exe -i '.\Awkward Megyn Kelly Interviews That Will Make You Cringe-KaAdS8Oso9U.mp4'
...
    Metadata:
      handler_name    : SoundHandler
    Stream #0:2(eng): Data: bin_data (text / 0x74786574), 0 kb/s
...

--embed-subs follows it and fails as seen from the log above.

Using --embed-subs alone works without any issue.