#1008 NORM Update.: Play MPEG-1 video is not smooth via MPEGPlayer.

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#1008: Play MPEG-1 video is not smooth via MPEGPlayer.
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  Reporter:  chiaying.lin    |       Owner:  etoys   
      Type:  enhancement     |      Status:  new     
  Priority:  normal          |   Milestone:  Update.2
 Component:  etoys-activity  |     Version:          
Resolution:                  |    Keywords:          
  Verified:  0               |  
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Changes (by bert):

  * milestone:  Opportunity => Update.2


Comment:

 (via email from John !McIntosh )

 Bert, I have a changed mpeg support file here.
 The decoder logic would use this, and other construct
 {{{
         d[0] = s[0]; d[1] = s[1]; d[2] = s[2]; d[3] = s[3];
         d[4] = s[4]; d[5] = s[5]; d[6] = s[6]; d[7] = s[7];
 }}}
 Basically moving one byte at a time, however a few years back I discovered
 this was a bottleneck in the mpeg frame performance and changed it  to
 {{{
         t1 = *(long *) s;
         t2 = *(((long *) s)+1);
         *(long *) d = t1;
         *(((long *) d)+1) = t2;
 }}}
 This made like a 30% performance gain in the powerPC frame rate.
 however because I could not test on INTEL I had coded it as __POWERPC__
 change only, plus at the time MMX was being used for Windows.

 In looking at the OLPC stuff I'm wonder if we could use the same code on
 INTEL.
 Thus I tried on my !MacIntel box and it seems to be ok.

 I've included the source file, perhaps you could compile up for OLPC and
 send us back a Squeak VM?
 You might want to see if it improves the OLPC EToy MPEG playback first
 tho?

 Look for the changes via
 {{{
  #ifdef __LONGMOVEMENTVERSUSBYTE__
 }}}
 Attachment: reconstruct.c

-- 
Ticket URL: <http://dev.laptop.org/ticket/1008#comment:9>
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