how can extract audio from a mkv file.. i've done it with ffmpeg but the output's quality was terrible..

do you knox any apps for doing that kind of thing with not loosing its quality.

platform: debian testing

What was the exact command you used? Because ffmpeg can rip the stream directly out of the container with no re-encoding.
If you pay close attention to the screen output while ffmpeg is running, you can see exactly what the input and output streams are encoded as.

1 members found this post helpful.

i used ffmpeg -i input.mkv -vn xxx.mpeg ( try to do mp3 but its not supported)

Well, ffmpeg's default audio format for the mpeg container is an mp2 stream, and its default bitrates are always set very low, so yes, that's what you got. I just ran a test myself, and the output showed this for audio:
Setting -acodec to copy will give you whatever the original stream is encoded as, no matter what the output filename is. Look at the corresponding input line.

But nothing's keeping you from configuring the command to make it give you the kind of output you want. Just read the ffmpeg man page and/or search the web.

As for mp3 support, it's usually handled by the external libmp3lame library. Run ffmpeg -codecs |grep mp3 and see if there's a line in it for libmp3lame with an "E" (for encode) at the front. Since mp3 is a patent-encumbered codec, I don't think the default debian version of ffmpeg has support for liblame enabled, but I may be wrong.

In any case, you can get better versions of ffmpeg and other similar programs by adding the debian-multimedia repository to your apt sources. These have most of the common codecs enabled. http://debian-multimedia.org/

Once you have a version with liblame support installed, just use -acodec libmp3lame in your command, along with -ab to set the bitrate you want, or -aq to set the quality level.

You can use mkvextract if you want:

First run:

You will get something like:
This tells you that track 2 is audio of type aac, so now you can extract it:

If it is mp3, just title it file.mp3. If you want to convert to another format see the howto I made (very bottom):
http://draconishinobi.50webs.com/linux/encoding.html

I refer to it myself, because I figured it out once, then forgot, because I didn't write it down. So I had to figure it out again, but this time I wrote it down.

As pointed out above, will extract the audio stream, where .ext would be something like mp3 or aac or whatever - you'l have to look it up with ffprobe first. Or alternatively you can use to dump the audio to a wave file.

Hi,
I am novice to Linux (Mint in my case) and I followed quite few forums to find working and easy solution. And the easiest for me is to use ... outsanding Audiacity (file/import/audio) and than (fie/export and choose mp3 in right down corner).
Have fun!

ffmeg is outdated guys, didn't you know?

^ erm.

firstly, it's ffmpeg.

can you substantiate this claim?
until you do, i object strongly.
quite the opposite actually.

if you want. https://en.wikipedia.org/wiki/Libav

I don't think the wikipedia article really settles the issue. https://lwn.net/Articles/650816/

Rather endless story. avconv vs ffmpeg.

i think you just made a 180 degree turn there?

anyhow, looking at both articles, it seems indeed that "libav is ffmpeg".
but 2 more years have passed since 2015.

anyhow, archlinux uses ffmpeg. searching package database for "libav" returns ffmpeg. it is not possible to install "libav" or "avconv". that is good enough for me.

avconv is actually the most recent, but ffmpeg claims to be the most maintained.

the way i understod that wikipedia article, avconv has been merged back into ffmpeg.
so that statement doesn't make a lot of sense.