[FFmpeg-user] Is mixing of audio channels happening by default in ffmpeg?

Sam Marrocco smarrocco at ringsidecreative.com
Thu Jul 18 17:08:27 CEST 2013

On 7/18/2013 10:34 AM, Tom Evans wrote:

-map 0 means add every input stream in to the output. You've said what
you want done with video, encode to prores_ks, and what to do with
audio, copy, you just need to either say don't add all streams (just
first video and all audio) or copy all input streams, including
metadata, and re-encode the video.

You can do both with -map, eg to not copy the metadata track:  "-map
0:v -map 0:a  -c:a copy -c:v prores_ks"
or to copy everything, but re-encode the video: "-map 0 -c copy -c:v prores_ks"

-c:v is an alias for -vcodec, -c:a for -acodec, in case you were wondering.

Thanks, Tom.
in order to get the video, 8 channels of audio and the ninth track TC (which can't be specified specifically) what you stated might work as:

-map 0:v -map 0:a

If I'm understanding this seems to indicate "copy all video tracks across, using my pre-specified video codec settings" and "copy across all audio tracks, using my pre-specified audio codec settings". The timecode seems to be brought across by default without specifying.

I'll test further, but this seems to do the job.

sam marrocco | chief technical officer

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