[FFmpeg-devel] [PATCH] Make VP3/Theora Decoder Much Faster
Sun Dec 6 14:19:56 CET 2009
On Sun, 6 Dec 2009, Jason Garrett-Glaser wrote:
> Attached is a vague prototype for something I didn't mention
> earlier--a DC-only iDCT, the same type of thing I wrote for WMV a
> while back. I don't have time to finish it right now, so I've
> attached a probably non-working but Basic Idea for it. It would need
> asm code too, which would probably be easy enough (just blatantly copy
> the h264 ones and replace the C code for calculation of the DC value).
>+ if (num_coefs == 1 && block)
>+ s->dsp.idct_dc_put( output_plane + s->all_fragments[i].first_pixel, stride, block);
>+ s->dsp.idct_put( output_plane + s->all_fragments[i].first_pixel, stride, block);
H264 does it this way because it has to keep track of num_coefs
anyway. But you're creating this variable, so you can check
index_of_highest_nonzero_coef == 0 instead.
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