[vdr] Re: DVD-AC3-Playback

["Uwe" <linux_dvb@uni.de>]

Hello Klaus

>From: "Klaus Schmidinger" Sent: Saturday, November 24, 2001 4:54 PM
>
> 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.
>
>

I can  play DVD with first AC3-Language (Englisch). The second Language
break the AC3 with ** CRC failed - skipping frame **.(testet with StarWars
EP1)
VDR-Files with AC3 play become good AC3-Sound.
( 2min --> 9 skipping frame (**CRC failed - skipping frame **) )


MFG ... Uwe