Am 08.06.2014 14:15, schrieb Dirk Ausserhaus:
On Sun, Jun 8, 2014 at 2:10 PM, Kostya Shishkov
<[email protected]> wrote:
On Sun, Jun 08, 2014 at 01:53:49PM +0200, Dirk Ausserhaus wrote:
Here's a patch that fixes decoding of Indeo 4 B-frames.
Looks correct. I should've done it long time ago and saved you some work.
Now the main problem is Indeo 4 B-frames reconstruction. For that I
need to modify IVI context to store the second pair of vectors (that
is not hard at all) and make it perform the averaging motion
compensation for B-blocks (that one seems to require some more
hacking).
It seems tricker than most codecs since in Indeo one does not add residue to
motion compensation but rather the othe way around so motion function will
have to do averaging inside before adding result to the block.
IIRC, it performs a simple averaging motion compensation like this:
(X + Y) / 2.
IIRC, it doesn't even do a proper rounding.
The tricky part was which frames to choose - two different kinds of NULL
frames (type 6 and 7) play the key role there.
I'll try to search my data for more information on this topic. Not sure
how sucessful it will be because alot of time has passed since I worked
on this codec...
Best regards
Maxim
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