[FFmpeg-devel] AMR-NB decoder

Vitor Sessak vitor1001
Wed Aug 5 19:48:08 CEST 2009

Hi, and good work!

Colin McQuillan wrote:
> Attached is a patch for an AMR-NB decoder.
> It is not bit-exact. 

Neither it could be, it is float-based. The best you could get would be 
a stddev of ~0.05.

> This makes it tricky to verify, but I have been
> checking that internal parameters match the 3GPP decoder for the AMR
> test sequences. The PSNR between the input and output is 3.90 to 8.42
> which is about the same as the reference decoder.

I suppose here you mean the stddev, not the PSNR. Also, what command are 
you using to compare the results? Are you setting elem_size to 2? Could 
you paste the output of tiny_psnr for the test vectors (and a real-world 
sample ideally)?


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