[FFmpeg-devel] Patch review request: 10bit DNxHD decoding support

[Maxim]

Joseph Artsimovich schrieb:
>> I'm currently working on a support for the 10bit IDCT (both SSE2 and Altivec).
>> Some minor modifications (regarding rounding constants) of the existing
>> functions (idct_altivec.c and idct_sse2_xvid.c) are required.
>> There are two minor issues:
>>     
> Have you already decided on how are you going to expose them via DSPContext, API wise?
>   

No, I'm going to post the adapted code and let the others (having more
experience on dsputils) decide how that should be called.

I assume we have to add a new algo constant like that:

idct_algo = FF_IDCT_EXT

and then let dsputil activate the proper transform code for us...

Another challenge will be to deal with pre- and postprocessing requiered
by some video codecs (DNxHD etc.) like adding bias value, clipping final
pixels and shifting them to fit the desired output format.
Doing such things in a separate step spends alot of additional
computation time for temporary loading/storing data. Maybe it makes
sense to distribute that transform as macro so the compiler can
eliminate unnecessary load/store code during optimizations...

Best regards
Maxim