[FFmpeg-user] swopping channels in a 5.1 layout

[Youri Feenstra]

That works great, thanks. One question though, how do I refer to a
inputfile for amovie which resides in another folder? I can't use a path
reference.

2012/1/29 Clément Bœsch <ubitux at gmail.com>

> On Sun, Jan 29, 2012 at 02:46:14PM +0100, Youri Feenstra wrote:
> > Hi all,
> > I'm trying to reverse left and right audio channels from a 5.1 audio
> source.
> > My command is
> > ffmpeg -i 6.wav -map_channel 0.0.1 -map_channel 0.0.0 -map_channel 0.0.2
> > -map_channel 0.0.3 -map_channel 0.0.5 -map_channel 0.0.4 -y 6rev.wav
> >
> > But the resulting file will sound exactly the same.
>
> Mmh indeed I can reproduce. I'm going to look what's going on here.
>
> > However, when I downmix to two channels, like so
> > ffmpeg -i 6.wav -ac 2 -map_channel 0.0.1 -map_channel 0.0.0 -map_channel
> > 0.0.2 -map_channel 0.0.3 -map_channel 0.0.5 -map_channel 0.0.4 -y
> 2rev.wav
> >
> > ...the resulting audio will have the left and right channels swopped. The
> > fact that this will be a 2-channeld audio stream isn't a big problem
> since
> > I'll be using this command on video files which I will play on my phone
> > with headphones.
> > But, downmixing results in a much lower volume, which is an issue for me.
> >
>
> You can use -rmvol option, or volume audio filter for this.
>
> > Does anyone know why the map_channel option won't work on a 5.1 output
> > stream?
> >
>
> Not yet. In the meantime, you can use:
>
> ffmpeg -f lavfi -i
> "amovie=6ch.wav,pan=5.1:c0=c1:c1=c0:c2=c2:c3=c3:c4=c4:c5=c5" as a
> workaround.
>
> [...]
>
> --
> Clément B.
>
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