[LAU] splitting video/audio and recombining

[Robin Gareus]

On 03/04/2012 07:48 PM, James Stone wrote:
> Hi List,
> 
> I have a video which needs a bit of eq'ing on the audio side. Can
> anyone point me in the direction of how to split the file into audio
> and video so I can apply some treatment to the audio, and then combine
> them back together again? The video is wmv at the moment, but mplayer
> doesn't seem to have any problem with it.
> 

#extract audio
ffmpeg -i orig_video.wmv audio_out.wav

#replace audio
ffmpeg \
  -i orig_video.wmv \
  -i new_audio.wav \
  -vcodec copy \
  -map 0.0 -map 1.0 \
  new_video.wmv


Details:  The "map" may be different depending on the .wmv file.
run `ffprobe` to see which is the video-track in the .wmv file
usually this is "0.0".
    Stream #0.0: Video:...
    Stream #0.1: Audio: ..
and "1.0" corresponds to the 2nd input file - your new audio.

You may want to add "-acodec wmav2" and "-ar 128k" options for 128kbit/s
Windows Media Audio 2 or whatever audio-codec/quality your want. `ffmpeg
-codecs | grep "EA"` gives you a list of available codecs for Encoding
Audio.

BTW. Ardour3 with videotimeline patch can do all this for you.
import,extract,re-encode using ffmpeg.

robin