[FFmpeg-devel] [PATCH] DCA - setup correct channel value when downmixing is required

[Nick Brereton]

On Sat, 2010-07-24 at 11:25 +0200, Benjamin Larsson wrote:
> On 24/07/10 02:49, FB2000 wrote:
> > Without this, trying to convert 5.1 DTS sample to 2 channels Wave with
> > command
> > 
> > ffmpeg -i sample.dts -ac 2 out.wav
> > 
> > always failed with error "Resampling with input channels greater than 2
> > unsupported", because avctx->channels still equals to 6.
> > 
> > 
> > 
> > Index: dca.c
> > ===================================================================
> > --- dca.c       (revision 24472)
> > +++ dca.c       (working copy)
> > @@ -1371,6 +1371,7 @@
> >          if (avctx->request_channels == 2 && s->prim_channels > 2) {
> >              channels = 2;
> >              s->output = DCA_STEREO;
> > +            avctx->channels = 2;
> >              avctx->channel_layout = CH_LAYOUT_STEREO;
> >          }
> >      } else {
> 
> Patch ok.
> 

I've attached an alternative patch here. This should work a bit better
as it will disable further XCh processing and allows selection of 5.1ch
output when the source material is actually 6.1ch.

The output from down mixing to 2 channels from 6/7 channel sources is
also broken (add_bias must be taken account of and the channel mappings
are wrong in the existing code) - that needs to be fixed in a separate
patch. Unless someone else has a go at it, I'll fix it later this
weekend.


> MvH
> Benjamin Larsson
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at mplayerhq.hu
> https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel

Cheers,

Nick
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