Re: Help needed

I've more or less understood their logic. Their intra blocks follow such 
scheme:
            LAST 4 ELEMENTS
             V       V       V      V
D0 -> +d00 +d10 +d20 +d30 -> D0
D1 -> +d01 +d11 +d21 +d31 -> D1
D2 -> +d02 +d12 +d22 +d32 -> D2
D3 -> +d03 +d13 +d23 +d33 -> D3
             V       V       V      V
           LAST 4 ELEMENTS
where D0-D3 - saved deltas, dxy - new delta for position x,y (note that 
+d00 +d10 means D0 += d00; D0 += d10; and the same for LAST 4 ELEMENTS)

Inter blocks (still, motion, update) also update deltas D0-D3 and LAST4, 
but somehow in another way.

Now my decoder decodes file tm20.avi from MPlayer samples repository 
with artifacts and in grayscale only, but nevertheless close to original.

Can somebody review this code and suggest how to correct and/or some 
optimise it?

P.S. I noted that even if I don't get helpful replies, my work goes 
better after such posts. Maybe it's time to open local BLOG :)