[MPlayer-users] [Fwd: dts decoding broken?]

Giacomo Comes comes at naic.edu
Fri Feb 9 18:34:24 CET 2007

On Fri, Feb 09, 2007 at 06:01:10PM +0100, mail at kraymer.de wrote:
> I accidently sent the following mail to ffmpeg-dev while I intended to
> post here..
> -------- Original Message --------
> Subject: dts decoding broken?
> From: <mail at kraymer.de>
> Date: Fri, February 9, 2007 5:52 pm
> To: <ffmpeg-devel at mplayerhq.hu>
> Hello,
> I recently noticed that dts decoding doesn't behave like it did before.
> Problem: Playing a 5.1 dts stream (either dvd or matroska in my case)
> results in only 2 channels being played without downmix. I only have a
> setup with two speakers, 5.1 ac3 streams are mixed down and it did the
> same with 5.1 dts. Now, I only get 2 out of 6 channels without downmix,
> even with -channels 2 and/or -af channels=2. What I get is mainly music
> and background sounds, voices are missing.
> I did some regression testing and it turned out that a change in ffmpeg,
> namely commit -r 7839, introduced that behavior. Using recent mplayer svn
> and changing ffmpeg externals to -r 7838 makes the problem go away.. I'm
> posting here because I couldn't reproduce the problem with ffplay. That
> doesn't mean the problem doesn't exist in ffplay, ffplay simply fails on
> the files I'm having the trouble with: a dvd vob (I think ffplay doesn't
> cycle through the audio tracks (one ac3, one dts) and doesn't like my
> matroska file at all, no sound with either -r7838 or 7839).
> Regarding samples, I'm sure the problem is reproducable with every 2.0
> setup and a dvd/mkv with dts track. If not, I'll upload parts of my
> files..
> Please find mplayer output (with ffmpeg -r 7839) attached.

Reimar recently changed dts decoding im ffmpeg in order to allow 6 channels dts
to be decoded as 6 channels. The problem now is that downmix is not working.
It doesn't matter the number of channels you request with -channels, always
6 channels are decoded. 
Reimar is this somenthig that should to be fixed in libavcodec or the fix
concerns mplayer?


More information about the MPlayer-users mailing list