[XviD-devel] SAD cache

[Radek Czyz]

Hi,
skal wrote,

>         so far I've seen, it's 10-20% hits for 'regular' fast moving
>         scenes. For slow moving ones (where the diamond/square search
>         does not wander too far), it raises up to 20-30%. Conversely,
>          for 'hard' scenes, it drops to 5%.

Ooooops, there must be a bug - a big one ;_; .

This could explain why dev-api-3 is slower than 0.91. At the very
beginning of my ME, it wasn't slower, so I thought it was not ME to
blame. It might be related...

>         An other advantage of caching is that it makes the code for
>         diamond-or-the-like search rather trivial to write...

There is more. To counter the double-checks, I 'invented' a very slow
loop called 'make_mask()'. It was slow, but my tests shown that it was
faster than double checks.
If we could replace it with a good caching system, it might be even
faster again.
And yes, it would also make diamonds shorter and easier - and, this
way, faster. 
I really like the idea.

Regards,
Radek