[vdr] vdr-xine buffer size for PAL only?

Reinhard Nissl rnissl at gmx.de
Sun Mar 26 23:57:15 CEST 2006


C.Y.M wrote:

> I was just reading the vdr-xine manual again and noticed this quote:
> "The buffer size is specified in video frames, where 25 video frames make up a
> buffer which can hold one second of audio and video."
> My question is, would it help for a NTSC only system to change the fps to 30?
> One second of video on NTSC is ~30 frames.  I guess I could just increase the
> buffer a little more for NTSC. Just curious...

No need to worry about that. I just took the unit frames to have nice 
little values for the setup menu. The entered number of frames is 
internally converted to seconds (= / 25.0) and the delta of VDR's and 
xine's PTS values is compared against it after conversion into seconds 
too (= / 90000.0).

So, no matter what frame rate your stream has: the buffer will always 
hold one second if you choose 25.

BTW: all vdr-xine releases before 0.7.7 had a logic error: they 
calculated the buffer size as the maximum of video and audio buffer, but 
that was wrong. The current releases take the minimum. That's why 
channel switching takes some time even if a buffersize of 0 is 
specified, and why one had to reduce the buffer size setting of previous 

Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl at gmx.de

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