MJPEG Tools Svn

Some minor, but important, fixes ...

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Fixed bug in SSE dist routines caused by changes in C (parameter no
longer provided) and tidied stuff up a little more...

Made fast quantisation code robust. It is now perfect for
all legal values for coefficients below 63 and gets than
0.1% wrong for big coefficients. Zoom zoom!

Slowly coming towards a release ... lots of untested code still !

This commit was manufactured by cvs2svn to create tag 'BetaRC1'.

Completed initial experiments with gradient descent.
Solved problem with inaccurate fast integer quantisation
calculations (for now.... maybe) and completed porting over
of available MMX routines. There's really very little left in
the code that can benefit from this. One or two more routines plus
extending the fast MMX stuff to the other quantisation routines.

Basically, if it survives a couple of movie-length tests its
ready for beta.

O.k. now the bugs are out some polish. First cut a faster C routines
for quantization. The job is completely done yet - need to tidy up
parameter usage vs. globals and do intra as well and non_intra.
However, it works and its a lot quicker (mainly due to avoiding
the dreaded integer divide (positively glacial on the x86).

The code is now in good share for MMX-ification. I'll probably do
it when I merge the remaining MMX goodies from bbmpeg.

Fixed some nasty and damn subtle bugs causing corruption of the
fast motion compensation data. Took *ages* to pin down...

Found that wretched bug in the the assembler that was
causing weird, rare, random misbehaviour. Guess who
wasn't saving a modified register. Eeeeee-orrrr....

Annoyingly the (whatever it was) random value of an uninitialised
variable was giving *excellent* quantisation bit-allocation.
I'll have to experiment to find it...