youtube-dl does not respect --audio-format if -o is used.

[rsd]

Somewhere in the last few weeks, something changed while using the -o option.

When extracting audio, if -o is used, the audio stream is copied (mp4) even when mp3 format is what was asked for.
This does not happen if -o is ommited.

$ youtube-dl --verbose --extract-audio --audio-format mp3 -o output.mp3 https://www.youtube.com/watch?v=NUbUen66Z0k

[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'--extract-audio', u'--audio-format', u'mp3', u'-o', u'output.mp3', u'https://www.youtube.com/watch?v=NUbUen66Z0k']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.08.28
[debug] Python version 2.7.9 - Linux-3.19.0-25-lowlatency-x86_64-with-Ubuntu-15.04-vivid
[debug] exe versions: avconv 11.2-6, avprobe 11.2-6, ffmpeg 2.7.2-1, ffprobe 2.7.2-1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] NUbUen66Z0k: Downloading webpage
[youtube] NUbUen66Z0k: Downloading video info webpage
[youtube] NUbUen66Z0k: Extracting video information
[youtube] NUbUen66Z0k: Downloading DASH manifest
[youtube] NUbUen66Z0k: Downloading DASH manifest
[debug] Invoking downloader on 'https://r3---sn-bg07dnl7.googlevideo.com/videoplayback?id=3546d47a7eba6749&itag=140&source=youtube&requiressl=yes&nh=IgpwcjAxLmdydTA2Kg0xNzcuODQuMTYwLjgx&mm=35&mv=s&ms=pm&pl=24&mn=sn-bg07dnl7&ratebypass=yes&mime=audio/mp4&gir=yes&clen=17733417&lmt=1440979396118884&dur=1116.531&fexp=9406124,9408086,9408511,9408710,9409069,9413208,9415365,9415436,9415485,9416023,9416103,9416126,9416686,9417707,9417828,9418153,9418391,9418448,9419550,9420021&signature=495A189E4ACEB04F0E8F379404B9E6C021B8A4F6.0FC58A47DF97875748AC60A3459CBB1A2CB4FD53&mt=1441058097&sver=3&key=dg_yt0&upn=NFbNDS8nK78&ip=200.150.103.150&ipbits=0&expire=1441086830&sparams=ip,ipbits,expire,id,itag,source,requiressl,nh,mm,mv,ms,pl,mn,ratebypass,mime,gir,clen,lmt,dur'
[download] Destination: output.mp3
[download] 100% of 16.91MiB in 00:49
[ffmpeg] Correcting container in "output.mp3"
[debug] ffmpeg command line: avconv -y -i output.mp3 -c copy -f mp4 output.temp.mp3
[debug] avconv command line: avprobe -show_streams output.mp3
[ffmpeg] Post-process file output.mp3 exists, skipping

$ file -i output.mp3
output.mp3: video/mp4; charset=binary

------------ WITHOUT -o ---------------------
$ youtube-dl --verbose --extract-audio --audio-format mp3 https://www.youtube.com/watch?v=NUbUen66Z0k

[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'--extract-audio', u'--audio-format', u'mp3', u'https://www.youtube.com/watch?v=NUbUen66Z0k']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.08.28
[debug] Python version 2.7.9 - Linux-3.19.0-25-lowlatency-x86_64-with-Ubuntu-15.04-vivid
[debug] exe versions: avconv 11.2-6, avprobe 11.2-6, ffmpeg 2.7.2-1, ffprobe 2.7.2-1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] NUbUen66Z0k: Downloading webpage
[youtube] NUbUen66Z0k: Downloading video info webpage
[youtube] NUbUen66Z0k: Extracting video information
[youtube] NUbUen66Z0k: Downloading DASH manifest
[youtube] NUbUen66Z0k: Downloading DASH manifest
[debug] Invoking downloader on 'https://r1---sn-jv2xauxaxjvh-jfce.googlevideo.com/videoplayback?id=3546d47a7eba6749&itag=140&source=youtube&requiressl=yes&mm=31&ms=au&mn=sn-jv2xauxaxjvh-jfce&mv=m&pl=24&ratebypass=yes&mime=audio/mp4&gir=yes&clen=17733417&lmt=1440979396118884&dur=1116.531&fexp=9408710,9408988,9409069,9412514,9412913,9415365,9415436,9415485,9415521,9415992,9416023,9416105,9416126,9416330,9416729,9417014,9417707,9418153,9418199,9418448,9419338,9420019&sver=3&key=dg_yt0&signature=66080A8EFEE9E5AA5D570D006248A8D0969116D7.98C1E7DDC799DE71E78EB093A8CAADF7737FD101&mt=1441065224&upn=khG4z5YRi-A&ip=200.150.103.150&ipbits=0&expire=1441086903&sparams=ip,ipbits,expire,id,itag,source,requiressl,mm,ms,mn,mv,pl,ratebypass,mime,gir,clen,lmt,dur'
[download] Destination: Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a
[download] 100% of 16.91MiB in 01:29
[ffmpeg] Correcting container in "Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a"
[debug] ffmpeg command line: avconv -y -i 'Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a' -c copy -f mp4 'Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.temp.m4a'
[debug] avconv command line: avprobe -show_streams 'Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a'
[avconv] Destination: Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.mp3
[debug] ffmpeg command line: avconv -y -i 'Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a' -vn -acodec libmp3lame -q:a 5 'Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.mp3'
Deleting original file Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.m4a (pass -k to keep)

$ file -i *NUbUen66Z0k.mp3
Leocádio José Correia - 26 de agosto de 2015-NUbUen66Z0k.mp3: audio/mpeg; charset=binary

[yan12125]

Forcing 'mp3' file extension confuses youtube-dl. The mp3 file is in fact m4a. Try:

$ youtube-dl --verbose --extract-audio --audio-format mp3 -o "output.%(ext)s" https://www.youtube.com/watch?v=NUbUen66Z0k

[rsd]

Thanks.

Can you explain that?
Why does -o is more important than --audio-format?

Regards,
-rsd

[yan12125]

With -o output.mp3, the downloaded file is named as output.mp3. youtube-dl thinks it's already an mp3, so no conversion occurs.

[alexmercerind]

This stack overflow helped me.