[vdr] Understanding AC-3

L. Hanisch dvb at flensrocker.de
Thu Sep 2 18:05:34 CEST 2010


Hi,

  Just an additional info for the ones who want to help - the pvrinput-plugin passes through the TS from the HD PVR to 
vdr, there's nothing changed.
  So hopefully the plugin is not the one to blame for... :-)

  I posted a sample PAT and PMT of the HD PVR in february, perhaps it can be used to clarify something.

  http://www.linuxtv.org/pipermail/vdr/2010-February/022400.html

Lars.

Am 02.09.2010 15:21, schrieb Rob Davis:
> Hi Guy's,
>
> How do you go about understanding AC-3 within a VDR context?
> (apart from reading up on it online - which now has my head spinning).
>
> I have a Hauppauge PVR-HD and two ATSC cards. The ATSC cards work as they should and with the new atsc/dn patch on
> 1.7.15 now have the correct dpids.
>
> However, if I turn on add new transponders or update pids, then my Hauppauge PVR channels lose their dpid values..
>
> Sep 1 19:10:33 oac vdr: [8186] changing pids of channel 920 from 4113+4097=27:0;4352=eng at 106:0:0 to 4113+4097=27:0:0:0
>
> If I keep automatic channel updates off, then xineliboutput and streamdev work for these channels, but vdr-vnsi (xbmc)
> and vdr-xine don't (no audio)..
>
> I'm assuming vdr parses the ac3 headers in some way and sends information onto the playback frontend. How would I go
> about seeing what those headers might be and looking into patching pat.c accordingly?
>
> I noticed all the comments about e-ac3 and wonder if a similar patch should be made for this device.
>
> As an aside, vdr recordings from these channels play back fine in vdr-xine.
>
> So, more specifically, I suppose I would like to know how to find out the STREAMTYPE:
>
> I'm pretty sure it falls under this:
>
> case 6: // STREAMTYPE_13818_PES_PRIVATE
>
>
> But I'd be interested in seeing the flow through this section of pat.c and what is happening.. Mainly to see if
> something needs to be forced on?
>
> I can create a five second VDR recording if someone wants to see what the TS stream looks like.. But I'd be interested
> in diagnosing it myself..
>
> Thanks.
>



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