[MPlayer-users] status of dca/dts decoder

[Carl Eugen Hoyos]

Andy Furniss <andyqos <at> ukfsn.org> writes:

> > It is supposed to work fine with MPlayer over HDMI to a
> > DTS-HD Master receiver, and of course it has to be "seen" first.
> > Could you elaborate?
> 
> What I meant was if I do ffmpeg -i or mpplayer -demuxer lavf it only 
> shows 5.1 - it does play as 5.1 OK (downmix not OK).

This is not unexpected:
DTS-HD Master 7.1 contains DTS 5.1 (lossy) information as "core" and 
some additional data for lossless (and the the two additional 
channels), only the 5.1 core can be read by FFmpeg.
(But I wouldn't call this behaviour "can't get it to be seen".)

> Of course I have don't actually know if I have valid files FWIW I was 
> looking at the 7.1 lossless ones from the dts section here -
> 
> http://www.demo-world.eu/trailers/high-definition-trailers.php

There is no reason to assume the files are defect / I am not sure 
if they decode at all if they are (sufficiently) damaged.

But as said, you can test with MPlayer and HDMI.

> >> Is the downmix from 5.1 to stereo known to have issues?
> >
> > I am not sure if I understand the question.
> > You can test the following:
> > $ ffmpeg -request_channels 2 -i input out.wav
> 
> This produces a 6 channel wav with four silent - the L&R do show the 
> issue in that they are not a stereo downmix and clip - they just seem to 
> be everything sent to to 1 channel then duplicated to make 2 (that may 
> not be an accurate analysis though).

Since this works fine here (stereo output):
Command line and complete, uncut console output missing.

> > $ ffmpeg -i input -ac 2 out2.wav
> 
> This produces a 6 channel copy with no downmix.

This sounds quite unbelievable since it is supposed to work 
for any input; since it works fine here:
Command line and complete, uncut console output missing.

("Works fine" does not mean that the stereo output fulfills 
any requirements, just that stereo output is produced.)

Afaict, MPlayer does - as I suspected - request two channels 
from the decoder by default.

Carl Eugen

PS: I tested hd_dts_animated_logo_lossless.m2ts