[vdr] Re: AC3 audio handling

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

On Mon, May 03, 2004 at 12:17:37PM +0300, Marko Myllymaa wrote:
> On Sat, 1 May 2004, Stefan Huelswitt wrote:
> 
> > On 30 Apr 2004 Ondrej Wisniewski <ondrej.wisniewski@ericsson.com> wrote:
> >
> > > The AC3 stream is not handled directly by vanilla VDR
> > > but needs the AC3overDVB patch (plugin?).
> >
> > The AC3overDVB patch encapsulates the AC3 stream into a format
> > which is passed through the DVB card. The actual decoding takes
> > place inside the DD-receiver.
> >
> > > Is there any possibility to have an "on the fly" conversion (downmix) for the
> > > AC3 audio to mpeg audio ?
> >
> > Certainly. You can find code for this inside the DVD plugin. It
> > does downmixing if used without AC3overDVB.
> 
> I have little question about AC3overDVB vs. downmixing in dvd plugin.
> Which eats more cpu? I've been so far using dvd plugin and had it downmix
> the ac3 sounds. It's working nicely, but I would still like more ac3
> sounds. But I'm not sure if my machine is enough for that.. P200MMX, with
> 64 megs of ram..

Downmixing requires more CPU due to the decoding of AC3 whereas
AC3overDVB patch and the bitstreamout plugin only read the AC3 data
from the Mpeg2 data container and put them into a PCM none audio
data container.  For AC3overDVB or bitstreamout a P200MMX is OK, but
64 megs of ram is very less memory and could lead to swapping.
IMHO you should use 256 MB.

> 
> Oh, one other question about dvd plugin. Why does it use hd so much? The
> hd led flashes all the time and dvd led only occationally. Afair xine did
> not use that much hd..

Don't know, you may ask the current developer if you're able reach him

        Sven Goethel <sven@jausoft.com>

_and_ get an answer.

          Werner


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