[XviD-devel] HUGE ME regressions between beta1 and beta2
Radek Czyz
radoslaw at syskin.cjb.net
Sat Nov 26 13:42:09 CET 2005
Now you see how strange it is :)
It would appear that we've got an impressive quality boost from your
patch. Initially you only saw that with higher quants, however *if* I
make all tables linear (same formula for low and high quants) then
there's a detectable gain in lower quants too.
I tweaked 8x8 lambda multiplier a bit and got some more.
If we keep this, I'll be happy to sacrifice some speed.
What I said above is true for no bframes.
Example I just did, quant 3, defaults, no bframes:
old code, size 43,010,048, psnr 44.1543, time 2:03
new code, size 42,905,600, psnr 44.1544, time 2:07
Funny, heh? It searches more and actually finds more. I'm happy with that.
With bframes, I get this:
old code: size 35,866,624, psnr 43.1332, time 2:01
new code: size 35,934,208, psnr 43.1822, time 1:52
So new and old are equivalent for psnr (more or less) with a rather
major slowdown. Whatever new p-frames got us, b-frames wasted.
I'll continue working on it now.
If I "fix" bframes, then I will highly recommend a simple patch that
changes 16x16 table to be linear. It looks like an unexpected win.
Radek
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