[mythtv-users] anyone have AC3/DTS passthrough working with revo 1600?

[Brian J. Murrell]

On Wed, 2010-06-09 at 10:12 +1000, Jean-Yves Avenard wrote: 
> Hi

Hi Jean-Yves,

Thanx much for your input on this.

> Very few (if any) TV have a AC3/DTS built-in decoder ; so it won't be
> able to play those on the TV directly.

I might be showing my ignorance here (which abounds in this whole AV
arena, so not surprising) but then how does my TV play the audio from
(clearQAM) digital cable channels, which can either be heard on the TV's
speakers or on the amp's speakers with the amp registering the input as
Dolby Digital?

Further, how can my TV play a video file that mplayer reports as having
a digital sound track:

Opening audio decoder: [liba52] AC3 decoding with liba52
dec_audio: Allocating 3840 bytes for input buffer.
dec_audio: Allocating 6144 + 65536 = 71680 bytes for output buffer.
Using SSE optimized IMDCT transform
AC3: 5.1 (3f+2r+lfe)  48000 Hz  448.0 kbit/s
A52 flags before a52_frame: 0x2A
A52 flags after a52_frame: 0xA
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 448.0 kbit/29.17% (ratio: 56000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)

via it's (the TV's) DLNA feature without an AC3[/DTS] decoder?  IOW, the
TV plays this file directly, from myth's UPnP/DLNA service, not decoded
and displayed by myth.

> When you're doing a connection like:
> PC -> TV -> Amp
> 
> in my experience, the TV only passthrough stereo PCM ; including over
> their digital out connector nothing else. At least that's what my Sony
> and Samsung TVs do.

Interestingly, my TV is Samsung Series 5 PN50C540
(http://www.samsung.com/us/consumer/tv-video/televisions/plasma-tv/PN50C540G3FXZA/index.idx?pagetype=prd_detail)

Also, my TV has a selector for its' SPDIF out (which goes to my amp of
course) on it to specify whether to output PCM or Dolby Digital, and the
DD option only appears to be selectable (i.e. not greyed out) when the
input is AC3 (and perhaps DTS, which I have not entered into this mix
yet) such as from clearQAM cable or Myth.  And when I select Dolby
Digital, the amp does register the input has being DD.  In the case of a
clearQAM cable signal, everything is fine.  I can hear the sound, in DD
on the amp.  In the Myth case, playing the file from which the above
mplayer output comes, the TV let's me select DD as the SPDIF format, but
the Amp doesn't seem to receive that.  Additionally, when the TV is set
to output on it's own speakers, it's just silent.

> If you want AC3/DTS passthrough, you have to connect your system like:
> PC -> Amp -> TV

My amp doesn't handle HDMI.  :-(

b.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part
URL: <http://mythtv.org/pipermail/mythtv-users/attachments/20100608/0344e804/attachment.pgp>