[FFmpeg-devel] [PATCH 2/2] DCA - fix downmix

[Carl Eugen Hoyos]

Nick Brereton <nick <at> nbrereton.net> writes:

> On 28 Jul 2010, at 13:58, Carl Eugen Hoyos <cehoyos <at> ag.or.at> wrote:

> > Before your patches, both lotr_5.1_768.dts and last_stand.mkv were

I meant: Before your first patches that introduced the seventh channel.

> > identified as 6-channel and if converted to wav, the resulting file played
> > "fine" (wrt channel order) with ffplay, mplayer and aplay (again analogue
> > and via hdmi).
> > Now the samples (at least with -acodec copy -f dts) are (correctly)
> > identified as seven channel, but the resulting wav file sounds completely
> > wrong (center channel missing?) with mplayer and aplay - this time only
> > analogue, because at least my receiver-hdmi combination (Geforce 210 -
> > KRF-V7300D) does not accept seven channel wav, only 1, 2, 4, 6 and 8).
> 
> This should be working with the last set of patches. It turns out that the
< MKV demuxer is forcing avctx->request_channels to 6 (even though the xch
> extension and 7 channels exist).

Yes, but that is not what I mean:
If you dump (or stream-copy) the dts stream of the mkv file, the resulting dts
file is correctly identified as 7-channel.
I do not know of a way to correctly (in the channel-order sense) play this
stream with FFmpeg's dts decoder except down-mixing.

There may of course be a problem with my setup, but at least it is (from my pov)
possible that nobody can play it, in which case I guess it qualifies as a
real-world problem.

Carl Eugen