[theora-dev] Multi-Thread Theora Encoder

Maik Merten maikmerten at gmx.net
Fri Oct 12 08:11:21 PDT 2007

Felipe Portavales Goldstein schrieb:
> The first fragment of the second half of the screen could use the last
> motion vector from the previous fragment on the first half of the
> screen. This LAST_MV mode is used to save the bits of a new Motion
> Vector added to the stream.
> But, when using the threads, if we want to run the motion vector
> search in parallel, we must avoid data dependencies between threads
> and therefore we loose a little compression.

Actually I wonder if it isn't feasible to do a "postprocessing" step
after motion search to search for missed LAST_MV opportunities, thus
restoring compression efficiency. The set of possibly affected fragments
(the ones on the thread "boundaries") is known or pretty small and I
guess it may be possible to do this rather fast.

Chances are I may be missing some obvious problems, though.


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