[linux-dvb] Re: AW: Re: AW: again: IS simultaneous recording of Video + AC3 "nearly" dropoutfree possible ?

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

On Thu, May 31, 2001 at 09:49:28AM +0200, Nils Heidorn wrote:
> >
> > Just set the AC3 PID instead of the "normal" audio PID.
> > I haven't tried this yet, but I would guess that this should record the
> > AC3 data. I am planning to implement multiple audio PID support, once
> > VDR 0.80 runs stable with the new driver. However, I don't yet know
> > how to output the AC3 stream. Maybe I'll just assume that there will
> > be a program into which VDR can "pipe" the AC3 data while replaying,
> > and that program will have to do whatever is necessary to replay the
> > digital sound.
> >
> > Klaus
> 
> Well that's no biggie in my opinion, i would do playback with the HW+ Card
> or burn it to DVD and let my Yamakawa do the playback :-)
> But of course it would be nice to have AC-3 playback in VDR too.
> When reading the opeinion that the DVB Cards are not able to playback AC3,
> then i sometimes ask myself if this is true, did you follow the *same*
> discussion about the D-Box 1 ???
> Now due to a New Firmware ( Dr. Overflow alias Uli ) it CAN passthrough raw
> SP-Dif, so it WORKS ...
> I wonder if the firmware guys could teach this to the DSP (?!?) in the DVB
> Card too ...

AFAIK ... after asking around ... the AV7110/AV7111 has a BUG in hardware
which means that is is possible but not usable.  Maybe someone knows
more about that?

> The other possibilities for you would be to playback AC3 via Soundcard with
> SP-DIF ( Like SBLive or Terratec 512i ) or via Hollywood+ MPEG2 Decoder Card
> SP-DIF ...

Yes I want to use a Dxr3 decoder card which is similar to the Hollywood+ MPEG2
decoder card (-> dxr3.sourceforge.org). The only problem is: There is no code
usable to redirect or bypass the sound to this card or its mapped device
within the DVB driver.  See driver/dvb at line 5482:

                case AUDIO_SET_BYPASS_MODE:
                        return -EINVAL;

... which isn't very useful, is it?

> 
> Thank you for those news, i hope you get VDR stable with the new API so we
> can see all your NEW ideas becaome real :-)

... and to make one thing more clear, the most questions about
DVB from customers of SuSE is _with_ VDR _and_ CDROM writer or one
of the new DVD writers.  Therefore OSD should not gone away ;^)


       Werner

PS:
IMHO the rare SDRAM/DRAM on the DVB card shouldn't be used for things
which could be done in normal system RAM in a similar matter
(which means with the same quality).  For an example see the newest
CVS shot of DVB driver in driver/dvb_demux.c  If I'm correct here(?)
it should be possible to define NOBUFS only if USE_OSD is not
defined ... and the memory leak within dvb_demux.c is IMHO
fixable by doing the vmalloc() only once if needed and vfree()
the buffer if the module is unloaded or ... if this isn't usable
(maybe ts_feed and section_feed are used at the same time) two
different buffers should be used, nevertheless IMHO the allocation
should be done only once and the disallocation before module unloading.


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