[vdr] Re: AW: Re: AW: Problem with DVD-AC3-Playback and VDR0.98

["Stephan Schreiber" <stephan@sschreiber.de>]

Sorry, if this gets too much off topic please someone tell me so.
I still think there are at least a few people out there with AC3 equipment
who are searching for an FAQ-style solution to this....


> -----Original Message-----
> From: vdr-bounce@linuxtv.org [mailto:vdr-bounce@linuxtv.org]On Behalf Of
> Dr. Werner Fink
> Sent: Wednesday, November 21, 2001 12:04 PM
> To: vdr@linuxtv.org
> Subject: [vdr] Re: AW: Re: AW: Problem with DVD-AC3-Playback and VDR0.98
>
> On Tue, Nov 20, 2001 at 11:40:00PM +0100, Stephan Schreiber wrote:
> > I experimented with lots of aplay options, but I only get
> intermitted white
> > noise.
> > The amplifier shows PCM and no AC3.
> > If you managed to get it working, would you please tell me the
> command line
> > you're using?

> Hmm ... strange.  Please be aware that the resulting PCM stream
> should _not_
> be remixed but simply looped through the sound chip to the S/PDIF
> out.  Then

Yes, I'm starting to realize that this might be exactly my problem.
I don't seem to be able to tell aplay how to do that.

I tried

cat [dvd]test.ac3 | ac3iec958 [-x] | aplay [-f dat] [-f S16_BE] [-M] [-D
hw:0,2]

in all permutations....
'hw:0,2' seems to do the same as 'iec958' or 'spdif', both options dont work
together with S16_BE.
The spdif in stays looped, and when I force it to be silent I hear strobing
white noise.
BTW: test.ac3 is a stream I got by replaying a VDR recording using the
option -a 'cat > test.ac3'.
ac3dec -C plays this one without any problems on spdif and my amplifier
shows "AC3 3/2.1" on its display.
dvdtest.ac3 is a stream I got the same way by replaying a DVD. It does not
work with ac3dec (stuttering and too fast, complaining about CRC all the
time).

> a modern A/V amplifier or receiver should be able to determine
> the data bit
> within the preamble of every PCM frame and this should cause to handle
> the embedded AC3 frames therein.

In my case, it doesn't. It works well with ac3dec however (only not with
DVDs as I mentioned before).

> The sample frequence is 48kHz (not 44.1 kHz), 16 bit, and the data is
> given in big endian.  You may switch this with `-x' option of
> ac3iec958 or try the format s16b with the option -f of aplay.  Some
> aplay's are patched (or from beta alsa tree) and have the options
> -P and -C (which means AES IEC95 professional and AES IEC95 consumer
> or in other words AES/EBU and S/PDIF)

I think, that might be the key to it?
I tried the latest (Beta 9) ALSA driver/lib/utils/tools as well as today's
CVS.
None of those aplay versions there has a -C or a -P option however....

How can I get that patched aplay? Is it a special SuSe version?


Greetings and thanks for your help
Stephan