[FFmpeg-devel] [PATCH] h.264: derive pict_type from slice_type

Michael Niedermayer michaelni
Fri Dec 14 01:38:14 CET 2007

On Sun, Nov 18, 2007 at 11:18:26PM +0100, Reinhard Nissl wrote:
> Hi,
> compared to the current implementation the attached version works like that:

> - for the first slice, pict_type is set to slice_type as before, but
> slice_type SI_TYPE and SP_TYPE are folded to I_TYPE and P_TYPE.

and why would we want that?

> - for any further slice, pict_type is changed to the folded slice_type
> when the latter uses more prediction (e. g. a B slice) than the current
> pict_type (e. g. a I picture).

probably ok

> - slice_type is only derived for frame pictures or the first field of
> field picture pairs. When the second field would be considered too, my
> samples would almost never yield pict_type = I_TYPE as they most often
> use I slices for the first field and P slices for the second field.

this is just not correct, you have to difference between a second field
just using the first for prediction vs. one using another field to decide
if its a I/P/B frame if you want to do it correctly, if not you can as
well leave it as it is

also this should be 3 patches not 1 as its obvious from above that there
are 3 seperate issues

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
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