[FFmpeg-devel] [PATCH] QCELP postfilter

[Daniel G. Taylor]

On 04/13/2010 11:38 AM, Ronald S. Bultje wrote:
> Hi,
>
> On Wed, Apr 7, 2010 at 4:42 PM, Michael Niedermayer<michaelni at gmx.at>  wrote:
>> the problem i have with this is that we dont know if the ffmpeg decoder
>> is correct. It feels like building on an unsound foundation.
>
> It's what we have, I'm OK with saying it's incorrect but can't fix
> that, at least not now.
>
>> i really would like to start with a qt decoder vs reference decoder vs
>> ffmpeg with reference postfilter.
>> also a more varied sample, that is female + male voice might be a good
>> idea.
>
> http://people.gnome.org/~rbultje/ff/
>
> There's the source (lossless flac, female voice, counting 1-20 and
> on), the converted QCP (using Qualcomm Purevoice software) and the
> output of the Qualcomm Purevoice software with that file.
>
> then there's 3 numbered wavs. They are FF decoder with reference, my
> or no postfilter. Please rate against the reference decoder and
> against each other and tell me which is best.

In my opinion the numbered samples are all very, very close. I think 
that 2 and 3 sound better than 1, but that's about all I can contribute. 
To me it sounds like there is a very small amount of noise in the 
background of 1 at times. 2 and 3 sound cleaner/smoother but the 
difference is very small.

Take care,
-- 
Daniel G. Taylor
http://programmer-art.org/