[Ffmpeg-devel] channel ordering and downmixing

[Uoti Urpala]

On Fri, 2007-04-06 at 20:17 -0400, Justin Ruggles wrote:
> Michael Niedermayer wrote:
> > On Thu, Apr 05, 2007 at 04:47:56AM -0400, Justin Ruggles wrote:
> >>+const AVChannelLayout mono_channel_layout = {
> >>+    .channels = 1,
> >>+    .mask     = CHANNEL_MASK_MONO;
> >>+    .layout   = { CHANNEL_CENTER, },
> >>+    .mono_downmix   =   { 1.000, },
> >>+    .stereo_downmix = { { 1.000, },
> >>+                        { 1.000, } },
> > 
> > 
> > this looks wrong IMHO, 2 speakers sound louder then 1 so it shouldnt be
> > all 1.000
> 
> You're right.  Keeping with the same scheme I was using, both should be
> 0.707.

I'd expect a mono->stereo conversion to copy the sound to both channels
unchanged rather than lower the volume. IMO it doesn't make sense to say
that stereo supports louder sounds than mono because you can add up the
channels - normally you'd take that into account in the overall system
volume.