[linux-dvb] Re: VDR Playback not smooth ?

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

ma.hoff@bigfoot.com wrote:
> 
> Hi,
> 
> as played around with VDR a little bit more I found out that the playback of recordings doesn't seem to be smooth. I mean that 1 or 2 times each second the playback stops for one frame and then skips one frame.
> One can see this the best if you have an object moving from left to right or vice versa. (otherwise it's no so obvious) The best is some kind of scrolling text. This seems to stop and then jump. I hope one can understand what I'm trying to say...
> 
> So I thought of a performance issue - but CPU showing in top is almost 98% idle, hdparm tells dma is on.
> Maybe it is some kind of muxing problem with the recorded files ?

The problem ist in the bad multiplexing of the data delivered from the driver.
VDR merely stores what the driver delivers.

Marcus explained the reason in his posting

   http://linuxtv.org/mailinglists/linux-dvb/msg04460.html

Apparently the core problem is that audio packets arrive too late.
According to his drawing titled "better PES" it should suffice to
"simply" insert the audio packet earlier in the data stream, which
means (part of) the video data would have to be held back until the
next audio packet has arrived. However, I don't know if that's possible
in the driver.

The next version of VDR (based on the new API) will read the Transport
Stream from /dev/ost/dvr and use code taken from 'tuxplayer' to store it as
"multiplexed PES". But still, the result will only be as good as the data
delivered by the driver...

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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