[vdr] Re: DVD-AC3-Playback

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Andreas Schultz wrote:
> 
> Hi all,
> 
> There have been to much complaints about DVD AC3 playback. So i had
> quick look at it.
> There appears indeed to be a problem with the way how DVD AC3 frames are
> sent to external decoders.
> 
> Everyone with problems, could you please try to modify line 772
> (cPlayBuffer::PlayExternalDolby()) in dvbapi.c.
> 
> orignal:
> 
> int written = b[8] + 9; // skips the PES header
> 
> should be changed to:
> 
> int written = b[8] + 13; // skips the PES header
> 
> This will most likely break AC3-out for DVB streams.
> 
> Please report your findings ASAP especialy wether this change indeed
> breaks DVB AC3 or not.

I don't have any detailed information on this AC3 (header) format,
but from what I have observed there might be a chance to dynamically
detect whether these four bytes should be skipped or not.

Please try this instead of the above change

           int written = b[8] + 9; // skips the PES header
           if (b[written] == 0x80)
              written += 4;

and test if this can play AC3 sound from DVDs as well as DVB
recordings made with VDR.

Note that this is just a wild guess - if anybody can come up with
information on how one can correctly detect whether these four header bytes
are present or not, please let me know.

Klaus
-- 
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Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
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