how to encode ONLY the audio track from a mp4 video file ?

[Michael REMY]

hi,

i have a video file whose extension is MP4.
The video codec is H264
The audio codec is MP2


i wish to rencode the audio part ONLY without touching/recoding the video part.

how can i do that ?
i am familliar with MKVtoolNix but it only works on .MKV file where you can add/extract audio track how we went.

is there any MP4toolNix alike software to do that ?

thanks for help or advice

Best Regards

Mike

[racer-x]

XmediaRecode. Set Video= copy and Audio= re-encode.

[Michael REMY]

XmediaRecode. Set Video= copy and Audio= re-encode.

thank, i will give it a try !

[Hoser Rob]

Avidemux will work too. Set video to copy and audio to whatever.

[videobruger]

And yet another options: MediaCoder. Besides doing a Copy for the video part you can disable it altogether just making an audio track.

[Shaylen]

mp4box. It's a little more complicated because there is no UI, it's a cmd tool.

Here's an e.g. on how to extract an audio track from .mp4
But first you need to know the index of the track if you want to extract it.
In mp4, index starts from 1 but in mkv it starts at 0 (Just a by the way).
Also you need to know the codec to know it's extension, Download MediaInfo, it's awesome.

mp4box infile -raw trackid:output="outfile.*"

As for encoding, search for audiocoder. I used it in the past, I'm not sure of the programs current state though.

To add back to mp4 file (I recommend you create a duplicate cause this is permanent, in case you make a mistake):
mp4box file -rem trackid -add "file":name=""

Good luck !!