Extract audio from webm video into m4a audio files

Question

Can I use ffmpeg or another command-line tool (I recently downloaded mkvtoolnix for example) to directly extract audio into m4a files from webm videos?

I've previously been doing this 2-step process:

ffmpeg -i input.webm temp.mp4
ffmpeg -i temp. mp4 -vn -c:a copy audio.m4a

Problems are that the first command is so slow, seemingly needlessly slow as the second command completes consistently in less than a second. Also, it's a pain to have to alternate between the two different commands.

Is there a single command I can use to put the audio of a webm video in a .m4a audio file?

I am also looking for a solution for .mkv files

Goddart

Answer 1

FFmpeg only writes AAC / ALAC / AC3 codec audio to M4A, normally not featured in WebM containers, so you will have to use

ffmpeg -i input.webm -vn audio.m4a

Crater

I'm embarrassed I didn't even try this. Why does mp4 require the -c:a copy? – Goddart

It doesn't. If the output format supports the input's audio codec, then -c:a copy is preferable since it skips recompressing the data. But you can always transcode. – Crater