[vdr] Re: AW: EPG scan cause high load and AC3 drop outs

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

On Fri, Mar 21, 2003 at 07:31:26PM +0100, Dr. Werner Fink wrote:
> On Fri, Mar 21, 2003 at 07:19:24PM +0100, Roland Praml wrote:
> > > > I don't know if I can track down my problem to the AC3-Plugin, but
> > > > the crash occured under the following conditions:
> > >
> > > Are you refering to the bitstreamout plugin or to the AC3overDVB
> > > patch?
> > 
> > Sorry, I'm refering to the bitstreamout plugin.
> > 
> > Maybe silly question:
> > Is it also possible to use LiveAC3 with the --audio=... option of
> > VDR?
> 
> If you've applied the audio patch of the bitstreamout plugin you
> may replay with the --audio option.  Nevertheless, the question
> is: what's the reason of the IRQ flood.

Hmmm ... thinking about.  Let's see, one AC3 frame from Pro7 takes
32 ms and has, toghether with the PES header within the MPEG2 stream, 1806 Bytes.
For one second we have there for 1806 Bytes * (1000ms / 32ms) ...
now the transport stream (TS) for the PES over DVB is splited into
184 Bytes payload + 4 Bytes for control.

1806 Bytes * (1000ms / 32ms) / 184 Bytes leads to 306 per second TS frames
and maybe every of those frames requires on IRQ for getting such frame
from the DVB card into the memory of the PC.

The bitstreamout plugin uses the VDR interface for getting the TS
of the AC3 stream from the DVB card.   Together with the data streams
for EPG this may sum up.



        Werner


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