[vdr] Re: AC3 over DVB-s is possible - Part2

[Wolfgang Fiesel <fie@iis.fhg.de>]

Roland Praml wrote:

> > Roland Praml wrote:
> >
> > > Is it possible that my receiver can't handle the wrapped AC3-Data.
> > >
> >
> > I don't think, because the receiver recognized correctly the DD mode
> (2/0 -
> > 3/2) and this is only possible if the receiver can decode the first bytes
> > (3-4) of each AC3 burst. Therefore it detects the start of an AC-3 stream.
> But
> > what's about the end ??
> >
> > Can you test the receiver on other HW (DVD player ) ?
> > Did you ever hear DD sound from the reciever ?
>
> The receiver works with an HW DVD-Player.
> Also with the SPDIF-out of my soundcard.
>
> >
> >
> > >
> > > I've tried the following things:
> > > -original VDR patched with the AC3-Patch
> > > -driver from 20.01 (and also current cvs version)
> > > -replay recordings from Pro-7
> > > -replay a DVD
> > > -connected directly and via voltage divider to the coaxial-in. (line is
> ~2
> > > m)
> > >
> > > -build a quick'n dirty TOSLINK interface
> > > http://members.tripod.com/~Psych/super-cheap-toslink.html
> > > and connect it to an optical in (I'm surprised, it works)
> > >
> > > The result is every time the same:
> > > Normal PCM-output works
> > > Receiver recognizes DD 2/0 or DD 3/2 input but stays quiet
> > >
> > > did I forgot something? do I have to add parameters to VDR?
> >
> > Do you use the -a switch ? (if yes, it's not more necessary)
>
> No, i started vdr without any switches
>
> > No, I should be work without any additional parameter. How did the analog
> > sounds (please careful, it's noise, but it's a regular puls sound, or do
> you
> > hear any irregularity in rhythm.)
>
> It's a regular puls sound (hacked with about 20 Hz)
> Sometimes it stops for 1 second and VDR reports "buffer empty"
> (maybe my machine is too slow, AMD K6-400)
>

Ok, now we try to make a special test to hear if we get any buffer
underrun/overflow.

1. Open the file ./VDR/ac3dec/decode.c
You will find two defines with #define AC3OUT --> rename both defines like this
#define AC3OUTXXX

2. <make clean> from the VDR path and recompile it again (some switches like
before +AC3=1)

3. Now listen to the digital SPDIF. Every AC3 stream will now be decoded by the
ac3dec library (like in case of DVD). Do you hear any audio breaks ?

Wolfi


>
> Roland

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Dipl.-Ing. Wolfgang Fiesel                   EMAIL: fie@iis.fhg.de
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