[Libav-user] Questions about ffmpeg's image conversion

Carl Eugen Hoyos cehoyos at ag.or.at
Sun Mar 10 09:48:58 CET 2013

Kai2 Li <likai2 at ...> writes:

> In my project, ffmpeg's image conversion call function
> yuv2rgb_c_32 in C file 
> /libffmpeg/libswscale/yuv2rgb.c

(This should not happen on x86 where optimized functions 

> With your please, I would like to ask some questions.
> a) Why the function writing by macro?  
> b) Whether the function can be optimized?
> c) Has there some updates or new version?
> d) Will ffmpeg have ARM platform specialized version or patch?

> My hardware is Sumsang Pad GT-P5110 (1G dural core, 
> 1G RAM, 32G SD card), ffmpeg version is 0.11.1

Is this ARM hardware?
If yes, nobody added arm optimizations for libswscale 
so far, look into the subdirectories in libswscale to 
see some examples (x86, ppc, sparc and bfin, consider 
looking at sparc if you really only need yuv2rgb32, 
x86 contains a myriad of optimizations more).

If you plan to work on adding optimizations, please 
update to current git head and please read 
(And if you plan to implement this, ffmpeg-devel is 
of course the right mailing list for implementation- 
related question, it isn't clear to me though if 
you want to do that.)

Carl Eugen

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