[vdr] FF card A/V sync suggestion

C.Y.M syphir at syphir.sytes.net
Fri Oct 20 23:22:30 CEST 2006


C.Y.M wrote:
> Udo Richter wrote:
>> Tero Siironen wrote:
>>> However, like Pasi Juppo told earlier in other thread, in last weeks
>>> episode
>>> of Lost there was many fadeout-fadeins between scenes and a/v desync
>>> happened on every one of these.
>> I've 'heard of such problems' on ATV+ and Lost. Whenever there's a fade
>> into black, the data stream seems to get stuck, frames get delayed, and
>> as consequence A/V desyncs and playback gets jerky, with lots of audio
>> and video frame drops. This can be fixed by pausing and jumping a few
>> frames backwards.
>>
>> My theory is that since audio is typically 600ms ahead of video, maybe
>> the audio buffers run over. Strange thing is why this happens
>> reproducible on blackness. Maybe due to extremely low bit rate in this
>> situation, more frames get packed into one data block, causing data flow
>> to be disturbed beyond some limit. It cant be too high data rate, ATV+
>> has just 2mbit avg, 4mbit max data rate.
>>
> 
> This theory sounds reasonable.  Any idea on a way to fix it? The biggest
> question is if it can be fixed from within VDR's source code or if it would
> require an additional firmware/driver revision.  I have given up hope on it.
> The only way I know of that is reliable is using software decoding.
> 

But, the biggest question is.. why does the ONLY happen when playing back
recordings??

Best Regards.




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