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<DIV><FONT face=Arial size=2>Hello,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I have found a situation in which this patch is
very useful. I've been testing with various raw HD clips available from an FTP.
I can provide the link if required but I haven't got it to hand.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The raw source is the bluesky.yuv clip. It
is 1920x1080 25fps progressive YV12/I420. (I don't remember which.) I have
resized it to 720x400 and have encoded at a lowish bitrate of 1Mbps. The
background is a sort of gradient between orange and lighter orange. When the
camera pans the blocks in the sky move abnormally and then jump every so often
which looks very bad. I tried a number of different things to avoid the problem
but the only thing that had any significant effect was the RD P-skip patch that
Loren wrote but never committed.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Here is a clip of the current revision without the
P-skip patch:</FONT></DIV>
<DIV><FONT face=Arial size=2><A
href="http://www.swains.plus.com/x264/x264.274.vanilla.mp4">http://www.swains.plus.com/x264/x264.274.vanilla.mp4</A></FONT></DIV>
<DIV><FONT face=Arial size=2>And here is one with the patch:</FONT></DIV>
<DIV><FONT face=Arial size=2><A
href="http://www.swains.plus.com/x264/x264.274.rdopskip.mp4">http://www.swains.plus.com/x264/x264.274.rdopskip.mp4</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>As you see it's quite an improvement. Not perfect
but pretty good.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Would it be worthwhile committing the patch for
this purpose? I'm thinking probably not, but is there some way we could alter
the patch such that the RD P-skip code is used only when there's very little
texture in the block as this would appear to be when it's most
effective?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Robert Swain (a.k.a. superdump on
IRC)</FONT></DIV></BODY></HTML>