Redundant postprocessor for "--extract-audio"

[epitron]

It looks like the postprocessor isn't needed anymore when you use --extract-audio on a youtube url:

$ youtube-dl --extract-audio https://www.youtube.com/watch?v=vWD7k6TrJ-g
[youtube] Setting language
[youtube] vWD7k6TrJ-g: Downloading webpage
[youtube] vWD7k6TrJ-g: Downloading video info webpage
[youtube] vWD7k6TrJ-g: Extracting video information
[download] Destination: Chromatics - Tick Of The Clock.m4a
[download] 100% of 4.37MiB in 00:01
[youtube] Post-process file Chromatics - Tick Of The Clock.m4a exists, skipping

It saved it directly to an m4a audio file, but still tried to run the audio extraction postprocessor.

Maybe a simple solution is to have the postprocessor ignore audio files (m4a, mp3, etc.)?

[jaimeMF]

You may want to convert it to another format using --audio-format.

[tewe]

Asking YT for M4A always results in broken files for me, so I want an option to force downlading of the MP4 and post-process to M4A locally.

[phihag]

@tewe Can you tell me where you did look for existing options that do that? -x --audio-format m4a -f mp4 should do what you want. However, it may be more beneficial to download the m4a file and reencode it, as suggested here.

[tewe]

Thank you. I did not cross my mind that when a post-processing option doesn't do any post-processing I might turn to completely unrelated options to fix that.

[sunk818]

@tewe > M4A always results in broken files for me

Winamp technical support said their player does not support MPEG DASH. This is what I use to convert m4a DASH audio to m4a AAC LC without losing quality.
ffmpeg -i input.m4a -vn -c:a copy output.m4a

@phihag > -x --audio-format m4a -f mp4

Will this parameter download the entire mp4 then extract the audio out of it? Are downloading more data we need then discard the video portion? If that is true, seems like we are wasting bandwidth unnecessarily?

[phihag]

youtube-dl 2015.01.23.4 and newer will automatically correct the header of the m4a file if ffmpeg is present on the system. I am therefore closing this issue. See our FAQ if you need help updating. Thank you for the report!