[Ffmpeg-devel] mpegaudiodec.c and armv5te optimizations

Benjamin Larsson banan
Thu Oct 5 08:39:17 CEST 2006

Siarhei Siamashka skrev:
> [...]
> That +-4 difference was just a quick and completely nonscientific
> observation of cmp output. To get valid test results of this quality
> reduction, surely proper tests are requred. Just got an idea, I did 
> benchmark a fast low quality build of libmad, it is interesting to check 
> not only performance but also quality for libmad as well. It may be that
> ffmpeg decoder  is somewhat slower, but has higher quality and that 
> could explain the results, so that could be considered a win already :-)
> But I have a few questions:
> 1. are there any tools that can be used for such tests? could they
> be 'audiogen.c' and 'tiny_psnr.c' from tests subdirectory in ffmpeg? if ffmpeg
> has some tools for audio quality regression testing, it would be stupid not to
> use them and invent something new :)
> 2. what audio file samples to use (for example testing on a file with a
> complete silence encoded would be stupid)? probably sound volume can
> probably also have some effect on decoding precision.
> 3. what to use as a reference mp3 decoder which is supposed to have ideal
> quality? or maybe just grab some audio CD, encode it (with something?) to
> different bitrates, decode it with different mp3 decoders and compare results
> against original CD file and not against a reference decoder?

I created some some software that could be used to test audio. Look 
through the archives. The best solution would be to fix my patches to 

Benjamin Larsson

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