[vdr] Falsche PTS im PES-Stream beim Spulen in Videoaufnahmen

Klaus Schmidinger Klaus.Schmidinger at cadsoft.de
Sun Dec 7 18:10:22 CET 2008


On 07.12.2008 15:29, Matthias Bauer wrote:
> Am 07.12.2008 um 00:38 schrieb Reinhard Nissl:
>> ...
>> I think that this manipulation could be done by VDR
>> generally and shouldn't cause any problems on FF-cards.
> 
> Yes, I also think so. Instead of fixing this in all plugins handling  
> with streams
> it would be better to fix this generally in VDR.
> 
> @Klaus Schmidinger: What do you think about this?

I'd like to avoid this if possible ;-)

The device gets told which trick speed mode to use, so why shouldn't
it be able to simply ignore the PTS values in trick speed mode?
The current implementation may be tailored towards the FF DVB cards,
but we can always make adjustments for a more general implementation.

>> Another idea: if you have a look into the MPEG docs, you'll find
>> a possibility to indicate trick modes in PES packets, and if I
>> recall correctly, it should be possible by just setting a single
>> bit. But I could be wrong and then it would be more complex than
>> the approach in the previous paragraph.
> 
> Yes, I found the trick mode flag in the documentation. This is probably
> the cleanest solution (if the decoder understands this). But it needs
> to insert 8 additional bytes into the packet header with additional  
> infos
> for the currently used trick mode. Possible trick modes are  
> fast_forward,
> slow_motion, freeze_frame, fast_reverse, slow_reverse).

I wouldn't want to modify the data in VDR. I'm just moving away
from extracting PES from TS and would like to keep the TS packets
as "black box" as possible.

I think it's better to persue a way in which the device knows that
we're doing trick mode, and then just ignores the PTS values.

Klaus



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