[Openchrome-users] [openChrome] #409: Poor XVideo performance on VX800

[OpenChrome Trac]

#409: Poor XVideo performance on VX800
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Reporter:  rafalbilski  |       Owner:  somebody
    Type:  defect       |      Status:  new     
Priority:  trivial      |   Component:  xv      
 Version:               |    Keywords:          
Blocking:               |   Blockedby:          
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Changes (by rafalbilski):

  * priority:  minor => trivial


Comment:

 I've been doing a lot of tests. There is nothing wrong with using HQV for
 XVideo. It gives superior picture quality.

 Loops are much shorter then 50ms. On VIA Nano 1,6GHz it takes 6,9us to
 execute this loop. But 50 * nanosleep(1ms) doesn't change a thing. Freeze
 time doesn't depend on loop time. Not 100% percent anyway.

 I think I know what's going on, but I don't have a clue why. Testing FLIP
 bit before entering PutImage() doesn't change anything. I've tried to test
 bit 3 (HQV idle) without success. For me it looks like FLIP bit gets
 cleared when
 HQV unit loads address and starts work.
 It looks like HQV unit on VX800 has a hardware limit of screen refresh
 rate frames per second. For example for me it is 60Hz and 60fps. If player
 will send two frames too close to each other HQV unit will drop first
 frame and starts from begining with new frame.  If frames are constantly
 comming too fast then nothing goes to framebuffer. For benchmark mode
 mostly it is 1 frame per second. For 70 fps freeze is noticeable, but it
 is very short.

 I've tried to check if VX700 is the same, but I can't as there is some
 other bug in Openchrome killing X server on it.

 If anyone has ideas where to look or what to test I will be glad to do it.

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Ticket URL: <http://www.openchrome.org/trac/ticket/409#comment:2>
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