[FFmpeg-soc] [PATCH] AMR-WB Decoder

Vitor Sessak vitor1001 at gmail.com
Sat Sep 4 20:16:26 CEST 2010


On 09/04/2010 05:22 PM, Marcelo Galvão Póvoa wrote:
> On 4 September 2010 06:02, Vitor Sessak<vitor1001 at gmail.com>  wrote:
>    
>> On 09/03/2010 11:50 PM, Marcelo Galvão Póvoa wrote:
>>      
>>> Also, whether with this patch or not I guess my output to the first
>>> sample above (attached) is not good compared to the reference decoder.
>>> The are some sharp peaks that can be seen with Audacity, one of them
>>> also with clipping. The stddev I've got seems ugly:
>>> stddev:  884.86 PSNR: 37.39 MAXDIFF:23298 bytes:   473600/   473600
>>>
>>>        
>> Indeed, the stddev is not particularly good, but don't trust only it to do
>> comparisons. A very small phase shift can completely ruin the stddev.
>>
>> Do you see sharp peaks in your output that are not there in the reference
>> decoder? Or the sharp peaks shows up when you invert and superpose the
>> waves? Do these sharp peaks gives audible artifacts?
>>
>>      
> Sorry, I've forgot to mention that I was comparing the reference
> decoder output waveform with mine. In general, they look mostly the
> same but there are some 3 or 4 points in which my decoder gives a
> short peak. I couldn't notice audible artifacts at these moments.
>    

It does looks like a bug :(

-Vitor


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