[FFmpeg-devel] [PATCH 13/39] lavc/ffv1: drop redundant PlaneContext.quant_table

[Anton Khirnov]

Quoting Michael Niedermayer (2024-07-18 00:32:38)
> the data for each decoder task should be together and not scattered around
> more than needed, reducing cache efficiency
> 
> putting all this extra code in the inner per pixel loop is not ok
> especially not for the sake of avoiding a memcpy of a few hundread bytes multiple levels of loops outside

A nice theory, but in practice this patchset makes single-threaded
decoding about 4% faster overall, on a 1920x1080 10bit sample. That's
just the ffv1 parts (up to patch 28), full set also improves frame
threading performance as follows:
threads         improvement
---------------------------
2                  52% (yes really)
4                  16%
8                  12%

-- 
Anton Khirnov