[MPlayer-cvslog] CVS: main/libmpcodecs ve_lavc.c,1.121,1.122

[Michael Niedermayer]

Hi

On Tue, Dec 27, 2005 at 03:59:23PM -0800, Corey Hickey wrote:
> Michael Niedermayer wrote:
> > ok, there are different macroblock types in b frames,
> > 1. forward predicted ones, they use the previous non B frame
> > 2. backward predicted ones, they use the next non B frame
> > 3. bidirectional ones, they use 2 vectors, one pointing to the previous frame
> >    one to the next
> > 4. direct ones, they are like 3. except that they store only one vector and
> >    calculate the second one from the colocated vector in the next non B frame
> > (this is what mpeg4 supports, other standards are very similar)
> > 
> > now 1. 2. and 4. are the same from a motion estimation point of view, just
> > find the best single vector using your favorite ME algorithm for P frames
> > 3. has 2 vectors, previously we simply used the vectors from the forward
> > and backward searches without refining them, now bidir_refine does a simple
> > 4-dimensional diamond like search with the number affecting the shape of
> > the used diamond, (larger number is slower)
> 
> Thanks for the explanation. I think that makes sense to me. Would the
> following be appropriate for the man page?
> 
> bidir_refine=<0-4>
>     Refine the two motion vectors used in biderectional macroblocks,
>     rather than re-using vectors from the forward and backward searches.
>     This option has no effect without B-frames.
>        0    Disabled (default).
>        1-4  Use a wider search (larger values are slower).

ok

[...]
-- 
Michael