Extract audio from MP4

[aiyoyo]

Hi all,

Here is a mp4 file I download from youku.com.
http://aiyoyo.getmyip.com/video/03000809064BD8557A923D028D906B78CEF4AA-9716-BEA7-4C0C-...D220B93072.mp4 (a part file of a game video)

I am able to to view it perfectly with media player classic, with audio and picture. But whenever I try to extract the audio file(AAC), the aac file is corrupt(play with media player classic, got sound for 2 seconds, the rest is garbled).

The program I have tried is: yamb, mp4box, winff

What I do not understand is, why I can play the video in media player classic 1.4.1.2845, but after I extract the audio, it is corrupt and unplayable. It work for the other part of the video.

Hope someone here can point me to somewhere. TQ

[bat999]

Hope someone here can point me to somewhere. TQ

Hi
You're right, when the audio is extracted with YAMB there is only a few seconds.
I've extracted it OK using FFmpeg, like this:-

ffmpeg -i filename -vn -acodec copy filename.m4a

[poisondeathray]

It also works if you mux with mkvtoolnix into mkv, then mkvextract

So it must be a bug with mp4box, or that specific version of mp4box

[aiyoyo]

Thank you guy for all your reply. I will try the program you guy suggest after work.

I use Allok video joiner to join the file., and found the sound problem, so that's why I try to extract the audio out and remux again to see if solve the problem. That's said, I think maybe Allok video joiner use same routine as mp4box/yamb to extract the audio when joining the video.

As for ffmpeg solution, isn't it winff use ffmpeg?

[therock003]

This seems to be an old thread but is ffmped still the best and easiest way to do this? I need to losslely extract audio from .mp4 youtube videos.

[Baldrick]

You can also use mp4box or a gui for it like mymp4boxgui. Under the demux tab.