[MPlayer-dev-eng] [PATCH] New filter: vf_phase.c

[Ville Saari]

On Sat, Mar 27, 2004 at 10:51:13PM -0500, D Richard Felker III wrote:

> Like I said, both-unknown isn't needed or useful. The capture
> field-order is always known (the mpeg decoded exports it).

I'm trying to make the filter to make use of the field flags, but
I'm somewhat confused about the meaning of the bits in mpi->fields.
Could someone enlighten me please?

DVDs I tested set MP_IMGFIELD_TOP_FIRST, but there's no
corresponding flag for bottom-first, so I assume that it is
indicated by MP_IMGFIELD_TOP_FIRST being unset. But how is
the bottom-first case then differentiated from unknown field
order or progressive?

The mpeg decoder also sets MP_IMGFIELD_ORDERED and it gets cleared
if the filter examining the flag is not the first filter. This leads
to the assumption that top-first can be tested by:

  mpi->fields&(MP_IMGFIELD_ORDERED|MP_IMGFIELD_TOP_FIRST)==MP_IMGFIELD_ORDERED|MP_IMGFIELD_TOP_FIRST

and the bottom-first by:

  mpi->fields&(MP_IMGFIELD_ORDERED|MP_IMGFIELD_TOP_FIRST)==MP_IMGFIELD_ORDERED

But then many progressive AVI files get recognized as bottom-first and
DV-AVI, that really is bottom-first, gets recognized as neither, so
obviously I'm not on the right track.

-- 
 Ville