[FFmpeg-devel] [PATCH]levc/hevc_cabac Optimise ff_hevc_hls_residual_coding (especially ARM)

Carl Eugen Hoyos cehoyos at ag.or.at
Tue Jan 19 16:59:39 CET 2016

John Cox <jc <at> kynesim.co.uk> writes:

> >
> >I don't think that's right, and is a security issue.
> I added that line as (nearly) every other decoder in 
> liavcodec has it -


> in particular h264_cabac.c has it.

Extensive testing was done before it was added.

Could you confirm how much of the speedup comes 
only from this change?

While we definitely all welcome a noticeable speedup 
of hevc decoding (and while my opinion on your patch 
has limited relevance) I believe that the patch 
absolutely has to be split: First step would be to 
have a split between changes in the general code and 
changes to arm assembly, I believe the first patch 
then may be split further.

I am a little surprised that you wrote some asm 
functions that are slower than what the compiler 
produces: Did you analyze this?

Carl Eugen

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