[linux-dvb] Re: video pts differences on dvb-t in the uk

[Måns Rullgård <mru@mru.ath.cx>]

Torgeir Veimo <torgeir@pobox.com> writes:

> On Sun, 2004-10-10 at 17:58 +0200, Ragnar Sundblad wrote:
>> --On den 10 oktober 2004 16:29 +0100 Torgeir Veimo <torgeir@pobox.com> 
>> wrote:
>> 
>> > I'm wondering if someone knows more about differences in video pts on
>> > dvb-t in the uk?
>> >
>> > I'm getting an a/v offset of about 160ms with both xawtv and vdr w/
>> > softdevice, and I've seen that PVAStrumento has an option for "relaxed
>> > video pts checks" for finish / uk dvb-t material.
>> 
>> In VDR recordings recorded from DVB-T in Sweden, the video pts
>> is often between 250 and 350 ms ahead of the audio pts.
>> I haven't checked the actual DVB stream from the demux device,
>> I have just assumed that this is more or less how it is
>> actually transmitted.
>> 
>> I thought it was done like this to give more time to the mpeg
>> decoding process, but I haven't checked it with the "reference
>> decoder model" or whatever it's name is.
>
> But surely the difference should be detectable in some way? I think the
> difference is less on some channels (TMF, some news channel). I delay
> video constantly by 160ms to compensate for this, but automating it
> would be preferable.

Are the PTS values offset from the true values?  Or are you using some
player that doesn't use PTS for synchronization?  Both sound pretty
broken to me.

-- 
Måns Rullgård
mru@mru.ath.cx