[FFmpeg-devel] [PATCH] avutil/motion_vector: export subpel motion information

[Clément Bœsch]

On Mon, Nov 23, 2015 at 03:54:19PM +0100, Michael Niedermayer wrote:
> On Mon, Nov 23, 2015 at 11:01:02AM +0100, Clément Bœsch wrote:
> > On Sun, Nov 22, 2015 at 04:27:02PM +0100, Michael Niedermayer wrote:
> > [...]
> > > > > IIUC src_x/y are only an approximation, as the exact motion vector
> > > > > isnt an integer in fullpel units so it would be mostly cosmetic
> > > > > if x + 4 >> 8, or /8 is used
> > > > 
> > > > yes
> > > > 
> > > > mpeg used x >> n, i replaced with x / (1<<n), but i could switch back to
> > > > the original shift, or even do x+(1<<(n-1))>>n if you want some rounding.
> > > > 
> > > > same for snow... what would you prefer? i have no real opinion, this code
> > > > doesn't interfere with normal decoding anyway (so performance is less
> > > > relevant)
> > > 
> > > i really dont know, i think something mostly symmetrical should be
> > > preferred so that for visualization the vectors arent biased in
> > > some direction
> > > thus a plain >> 3 might be bad
> > > 
> > 
> > So I kept the division, but hardcoded the 8 in snow.
> > 
> > Applied, thanks
> > 
> > BTW: can't we get more information on the "direction" (that is, the source
> > ref) for h264? Currently in the mpegvideo code, we have two ref possible
> > (forward and backward), but h264 (and maybe other similar codecs sharing
> > that code) can pick from more refs, right?
> 
> yes
> 

where can this information be obtained?

-- 
Clément B.
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