[vdr] Re: DolbyDigital (bitstreamout): Sound later than Pic...

["Dr. Werner Fink" <werner@suse.de>]

On Fri, Jun 13, 2003 at 05:18:23PM +0200, Mario Schellenberger wrote:
> Hello list,
> (i'm new to this list, so please tell me if i mail in a wrong format,
> etc. (i read the remarks mailed a few days ago!))
> 
> i just installed a fresh Suse Linux 8.1 on a clean HDD and afterwards
> set up the newest ALSA drivers and the LIRC daemon. Then i downloaded
> the newest DVB Firmware and the VDR-1.2.1 and installed them (as suggested in hubertus
> sandmanns instruction).
> afterwards i installed the newest bitstreamout 0.45d und everything
> works fine with my soundblaster live 1024 which is connected to my
> receiver via digital-coaxial cable. as soon as i switch to Pro7 (the
> only channel i receive that broadcasts DD (i.e. i can't try another
> channel) my receiver activates its DolbyDigital-Mode.
> But the sound is approx half a second too late. its looking quite
> strange if you see people talk but hear them later ...

In other words this delay is _always_ given on the very beginning?

Or does it happen after a few minutes or hours?  In the later case
the quart on the soundblaster is faster then the normal time used
by Pro7 (48kHz of the soundblaster != 48kHz of DD from Pro7).
This cause underruns of the sound buffer and the plugin will compensate
that (if VariableIO id set to yes) by doubling DD frames (one with
error bit set).  This works with my A/V receiver.

> 
> i don't know what to do about that problem! i had had setup a vdr with
> mp3, vcd and osdteletext plugin and thought they would interfere with
> bitstreamout. thats why i totally cleaned the hdd and made a plain
> installation with only DVB & VDR & bitstreamout running, but the delay
> is still there :-(

Hmmm ... IMHO this is not the reason.

> is my pc too slow? it is a celeron running at 533 mhz with 256 mb ram.
> i don't think the speed of the pc is the cause, because if i stop the
> live-signal and watch the time-shifted signal (pause of 1-5 sec)
> everything seems to be sync. recordings too seem to be ok, but i
> didn't yet test a longer recording to check if A/V stays in sync!

Your pc isn't to slow ;^)

> i would appreciate any help to this problem, i'm getting frustrated
> with that DD sound! ;-)

Try to play with the setup of the plugin. E.g. decrease the Delay
... if this doesn't help, set it to max (maybe we see an overrun
due slow initialization of the soundblaster).

If your soundblaster supports slave mode (this is the mode where
the reference clock is taken from the S/P-DIF in) then try to
enable this with S/P-DIF out from the DVB card connected to the
S/P-DIF in of the soundblaster.  Then all synch problems are gone.


      Werner


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