13 Jun
2005
13 Jun
'05
10 a.m.
Erik de Castro Lopo:
I was primarily testing speed, but both libraries where using the sinc
routine, so...
I recently did a lot of benchmarking between libsamplerate and mus_src
in clm/sndlib. My result was quite interesting, the fastest mus_src sinc
resampler where a lot faster than the fastest libsamplerate resampler.
I think most people would agree that speed is not the most important
aspect when measuring the quality of a sample rate converter.
With libsamplerate, I can state that the three sinc
based converters
have the following characteristics:
SNR Bandwidth
SRC_SINC_FASTEST 102.42 dB 80.23 %
SRC_SINC_MEDIUM_QUALITY 98.99 dB 90.68 %
SRC_SINC_BEST_QUALITY 97.43 dB 96.96%
where SNR is signal to noise ratio and Bandwidth its a percentage of
the theoretical best bandwidth (ie half of the minimum of the source
and desination sample rate).
He did, and Bil Schottstaedt used this algorithm as well for mus_src.
When I compaired mus_src with width=5, and libsamplerate with
SRC_SINC_FASTEST, the first one is much faster, I don't know what kind of
SNR/Bandwidth you get with your way of measuring when using mus_src with
width=5, but the source is easy to read so I guess you can figure it out.
--
A third program is the original sinc-resampler
from Julius Smith:
http://ccrma-www.stanford.edu/~jos/resample/
I don't know how this one performs compaired to the other two though.
libsamplerate the same algorithm as this one. I think Julius O. Smith
developed this algorithm.