[linux-dvd] video scrambling

["Marcus O.C. Metzler" <mocm@convergence.de>]

Michal Jeczalik writes:
 > 	Hello!
 > 
 > We have a problem. When we write() a mpeg2, first two-three seconds of the
 > spot are a little bit scrambled, both video and audio. What this may be
 > caused by? We have latest CVS version of drivers and RH 7.1 (with 2.4.4
 > kernel). This is NOT caused by disc I/O!
 > 
 > Anybody can help?
 > -- 
 > Michal Jeczalik
 > 
 > 

This is because of the autostart function of the decoding process. I
set a limit at which buffer filling decoding starts. If the limit is
to low, you get the effect you see. If the limit is to high it
sometimes won't start. But 2-3 seconds is a bit much. Usually I only
see it for a fraction of a second. What kind of mpegs are you writing?
Maybe their multiplexing is not so good.
If you want to play around with the driver, you can try to change lines
1087 ( if (vp > 90) { ) and  1101 ( if (ap > 90) { ) in decoder.c. The
90 stands for 90% buffer filling, thats when decoding starts. 

Do you use poll or select, to see if you can write to the device. It
could also be that you are not writing big enough blocks of data, or
maybe too big.

Regards

Marcus


---------------------------------------------------------------------
Dr. Marcus Metzler                             
mocm@netcologne.de                     http://www.metzlerbros.de
mocm@convergence.de                    http://www.convergence.de
Tel: +49(0)2234 433113

Convergence Integrated Media GmbH          
Rosenthaler Str. 51                   
D-10178 Berlin                             
---------------------------------------------------------------------


 >