Audio

Good settings for encoding to mp3

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I use Lame for encoding my recordings into mp3 format. I have experimented with many of the options and I have found that the following 3 combinations of command line switches produce excellent results: Small size, lossy: lame –alt-preset standard in.wav out.mp3 Good compromise between size and quality (VBR): lame –alt-preset extreme in.wav out.mp3 Large […]

Audio

Overlap-save method of block convolution for fast convolution on audio streams.

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Let $$\mathbf{h}$$ be a vector of size $$P$$ containing the impulse response you wish to convolve with, and let $$\mathbf{x}$$ contain an unknown number of float values which is the input audio stream. Note that an FIR filter can be expressed as follows: $$FIR(x[n],\mathbf{h})=y[n]=\sum_{j=0}^{P-1}({x[n+j] \cdot h[j]})$$ By chopping up $$x[n]$$ into sections of length $$L$$, […]