SSRC
(int samplerate, bool "fast")
SSRC
Shibata Sample Rate Converter is a resampler. Audio is always
converted to float. This filter will result in better audio quality than
ResampleAudio
.
It uses SSRC by Naoki
Shibata, which offers the best resample quality available.
Sampling rates of 44.1kHz and 48kHz are populary used, but the ratio of
these two frequencies is 147:160, and they are not small numbers. Therefore,
sampling rate conversion without degradation of sound quality requires
filters with very large order. It is difficult to achieve both quality and
speed. This program achieved relatively fast and high quality with two
different kinds of filters combined skillfully.
Parameters:
samplerate | Samplerate must be an integer. |
fast | This will enable faster processing at slightly lower quality. Set this to false when you are doing large samplerate conversions (more than a factor 2). Default: True. |
SSRC doesn't work for arbitrary ratios of the samplerate of the source and target clip. The following ratios are allowed (see SSRC.cpp):
sfrq = samplerate of source clip dfrq = samplerate of destination clip frqgcd = gcd(sfrq,dfrq) # Greatest Common Divisor fs1 = (dfrq > sfrq) ? sfrq / frqgcd : dfrq / frggcd Resampling is possible if: (fs1 == 1) or (fs1 % 2 == 0) or (fs1 % 3 == 0) example for which resampling is possible: sfrq = 44.1 kHz dfrq = 48 kHz frqgcd = gcd(44100,48000) = 300 dfrq > sfrq, hence fs1 = sfrq / frqgcd = sfrq / gcd(sfrq,dfrq) = 44100/300 = 147 and 147 % 3 = 0 since 147 = 3 * 49
The samplerate of your source clip can be found as follows
AviSource(...) Subtitle(string(AssumeFPS(23.976,sync_audio=true).AudioRate))
Example:
# Downsampling to 44,1 kHz: AviSource("c:\file.avi") # Has 48000 audio SSRC(44100)
Changelog:
v2.54 | Initial Release |
Some parts of SSRC is: Copyright © 2001-2003, Peter Pawlowski. All rights reserved.
$Date: 2012/04/15 14:59:42 $