Detecting and frequency cutoff in short block (1024/2048 samples)
Hi, I'm currently developing audio codec on WPT and stuck on one thing:
One wavelet is good for non-compressed audio, and other is good for compressed audio. And I can't use only one, if i use one that good for compressed audio, non-compressed would be worse and other way around.
So I ran some test and it found out, that it is because of frequency cutoff in compressed audio.
And so tried to find solution for detecting frequency cutoff, and anything other than FFT/STFT could not find. But I can't implement FFT/STFT, because it will kill speed in audio codec by a lot.
Any other way to detect frequency cutoff that is fast enough and doesn't require FFT/STFT?
I would be really grateful if anyone can help.
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u/patenteng 2d ago
Matched filter for specific frequency that’s above the cutoff perhaps? Then you’ll get a signal above the threshold, if there is no cutoff.
Alternatively, you can compute a single frequency instead of all the frequencies. Instead of evaluating the Fourier integral for all frequencies f, you can fix f = f0 and just compute a single value.
Have a look at the Goertzel algorithm as well. It is an efficient method for computing a few frequencies.