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2014/10/15 ¤U¤È 10:14:31

iphone Programming Glossary: stride

Using the apple FFT and accelerate Framework

http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework

don't actually make life any easier. Basically at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse.. at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to where we started. ip stands for.. the mic set log2n 10 2^10 1024 precalculate some bobbins setupReal and vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD Now A will contain n 2 complex numbers. These represent n 2 frequency bins bin 1 .idealFreq..

Using the apple FFT and accelerate Framework

http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework

stupidly obscure it is generously commented but the comments don't actually make life any easier. Basically at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to where we started. ip stands for in place.. the comments don't actually make life any easier. Basically at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to where we started. ip stands for in place which means A gets overwritten That's the reason.. is ie 1 44 s. So we would pack A with 1024 floats from the mic set log2n 10 2^10 1024 precalculate some bobbins setupReal and vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD Now A will contain n 2 complex numbers. These represent n 2 frequency bins bin 1 .idealFreq 44Hz ie The lowest frequency we can reliably detect..

Using the apple FFT and accelerate Framework

http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework

but the comments don't actually make life any easier. Basically at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to.. easier. Basically at the heart of it is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to where we started. ip stands for in place which means.. with 1024 floats from the mic set log2n 10 2^10 1024 precalculate some bobbins setupReal and vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD Now A will contain n 2 complex numbers. These represent n 2 frequency bins bin 1 .idealFreq 44Hz ie The..

iPhone FFT with Accelerate framework vDSP

http://stackoverflow.com/questions/6358764/iphone-fft-with-accelerate-framework-vdsp

stringWithFormat @ Read d bytes d packets numBytesRead packetsRead return result FFT code below log2n N n 1 log2n stride 1 nOver2 n 2 printf 1D real FFT of length log2 d d n n n log2n Allocate memory for the input operands and check its availability.. enough memory for the real FFT. n exit 0 Carry out a Forward and Inverse FFT transform. vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE Verify correctness of the results but first scale it.. out a Forward and Inverse FFT transform. vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE Verify correctness of the results but first scale it by 2n. scale float 1.0 2 n vDSP_vsmul A.realp 1 scale..

FFT on iPhone to ignore background noise and find lower pitches

http://stackoverflow.com/questions/7181630/fft-on-iphone-to-ignore-background-noise-and-find-lower-pitches

signal into even odd configuration vDSP_ctoz COMPLEX outputBuffer 2 A 1 nOver2 apply the fft vDSP_fft_zrip fftSetup A stride log2n FFT_FORWARD convert split real form to split vector vDSP_ztoc A 1 COMPLEX outputBuffer 2 nOver2 Demetri then goes..