[FFmpeg-devel] dv_guess_dct_mode

Michael Niedermayer michaelni
Wed Feb 4 23:00:39 CET 2009

On Tue, Feb 03, 2009 at 02:17:24PM -0800, Roman V. Shaposhnik wrote:
> Guys,
> the function dv_guess_dct_mode is used by DV codec to figure
> out whether the material is interlaced or not. Long time ago
> it was thought that we might eventually make such functionality
> part of dsputils. My brief look through the current state of dsputils,
> however, suggests that we don't have anything like that there yet.
> And now that I have to put a very similar code there for DVCPRO HD
> this begs the questions -- what would be the way to generalize it?
> Currently it only deals with a 8x8 blocks, but for DVCPRO HD it would
> have to deal with an entire frame, so... should I leave the special
> 8x8 version alone and introduce add a generalized one to the DV codec,
> should it all somehow be moved to dsputils.
> Comments are welcome.

see vsad_intra16_c() and ildct_cmp
these would need to be extended with a width=8 intra variant, arrays would
need to be enlarged to [6] ...

also supporting full RD would be nice, that is encoding both and picking
the actually better instead of some heuristic

and to handle the whole frame, one simply can repeatl use the 16x16 or 8x8

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
approximation. Benchmarking OTOH is finding an approximation of the exact
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