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

[Tom Evans]

On Thu, Jul 18, 2013 at 3:01 PM, Sam Marrocco
<smarrocco at ringsidecreative.com> wrote:
> Thank you for the explanation. I believe I now understand the issues better.
> So using -map 0 should "activate" the other tracks and "pass them through".
> The resulting output is:
>
>
> ffmpeg-20130507-git-399f6ef-win64-static\bin\ffmpeg.exe" -i
> "C:\Users\root\Desktop\MultiChannel.mov" -vcodec prores_ks -pix_fmt
> yuv444p10le -profile:v 3 -acodec copy -t 1 -map 0 -f mov
> "D:\\MultiChannel\MultiChannel.mov"
>
> ffmpeg version N-52837-g399f6ef Copyright (c) 2000-2013 the FFmpeg
> developers
> …
> Data stream encoding not supported yet (only streamcopy)
>
>
> No file is created--It looks as though the ninth track (apple timecode) is
> preventing completion using -map 0.
>

-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.

Cheers

Tom