[linux-dvb] Re: AC3 over DVB

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

On Wed, Jun 09, 2004 at 12:01:01PM +0200, Marcus Metzler wrote:
> 
>     Werner> The DVD uses a sub stream header within a private stream 1
>     Werner> PES, I've never seen one in the PS2.  Which DVD does this? 
>     Werner> AFAIK PS2 frames are for navigation data, arn't they?
> 
> Sorry, must have missed the key, off course I meant 1.
> 
>     Werner> Nevertheless bitstreamout and AFAIK the AC3 over DVB patch
>     Werner> vor VDR can handle both DVD and DVB AC3 data.  For an
>     Werner> overview how to get the AC3 data out from DVD streams see
> 
>     Werner>      http://mpucoder.kewlhair.com/DVD/
> 
> It is not the DVD handling. VDR seems to generate AC3 PES from TS that
> don't have the substream id. Getting the data is no problem. But if you
> don't have the header in a PES you can't distinguish the substreams and
> you don't even know if it is an AC3 without scanning for frame headers
> and that is not a sure way either. 

I know and if VDR will switch to more than one audio track for AC3
it is absolute necessary to include Audio Substream Headers.

> I don't know which version of VDR the guy who sent me the sample files
> from VDR was using, so it may already have been fixed. I didn't check
> the latest release.

The remuxer isn't very gentle. I'm missinig things like A/V sync and
checking the mpeg audio frames within the PES audio frames not to
cross PES boundaries  ... the same for the AC3 audio frames.  This
because it would make cutting much easier (no broken audio or AC3
frames on cut marks anymore).


        Werner

-- 
AC3 loop through sound card http://bitstreamout.sourceforge.net/
Howto http://www.vdr-portal.de/board/thread.php?threadid=1958
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