android - GCC_PHAT output -


i trying develop gcc_phat algorithm on android devices. fft used this library. idea correlate 2 audio files (16-bit pcm mono) find delay between them. matlab works perfectly. first problem fft output, gives numbers higher 32768. example:

fft re   -20830.895138576154 fft re   -30639.569794501647 fft re   -49850.48597621472 fft re   -49335.28275604235 fft re   -96060.94916529073 fft re   -91409.17426504416 fft re   -226903.051428709

is there way normalize these numbers interval of [-1,1]?

the library's forward transform definition match matlab's, should matching values after forward transform (not critical since g_phat normalized [-1,1]).

however, same cannot said of inverse transform. indeed code comments on inversetransform:

this transform not perform scaling, inverse not true inverse.

and library webpage:

this fft not perform scaling. vector of length n, after performing transform , inverse transform on it, result original vector multiplied n (plus approximation errors).

so, values matching matlab's fft/ifft implementation need divide result of ifft n.


Comments

Post a Comment

Popular posts from this blog

javascript - RequestAnimationFrame not working when exiting fullscreen switching space on Safari -

request animation frame stops working when exiting fullscreen clicking on original space's safari window. fine if fullscreen mode canceled escape key or calling cancelfullscreen(). steps reproduce: open https://dl.dropboxusercontent.com/u/769042/prezi/safari-fullscreen.html click "draw raf", kittie appears click "fullscreen", go fullscreen click "draw raf", kittie appears go space original safari was, showing "click exit fullscreen mode", click anywhere, out fullscreen click "draw raf", nothing happens what handling click calling: window.requestanimationframe(draw); which draws on canvas context: function draw() { ctx.drawimage(img, math.random()*500|0, math.random()*400|0, 100, 100); } i checked .hidden , .visibilitystate, updated correctly. tested on osx 10.9.3, safari 7.0.4 (9537.76.4). has workaround/solution other switching old settimeout? this sounds webkit bug 88940 : using reque
Read more

Python ctypes access violation with const pointer arguments -

i have api i'm trying wrap in python (2.7.6 on win7) code using ctypes. here's api: client_dllfunc bool clientapi search_exporttoclipcopy(clienthsearch handle, int channel, lpctstr filename, const time_t& from, const time_t& to, const bool* cameras, int length, bool usepassword, lpctstr password, bool includetextin = false, bool excludeplayer = false); the issue i'm having cameras argument; , i've had issue other const pointer arguments well. here's how i'm wrapping api: def search_exporttoclipcopy(self, hsearch, csearch, filename, tfrom, tto, cameras, length, usepassword, password, includetextin=true, excludeplayer=false): exporttoclipcopy = self.sdkdll.search_exporttoclipcopy exporttoclipcopy.argtypes = [c_int, c_int, c_wchar_p, c_long, c_long, pointer(c_bool), c_int, c_bool, c_wchar_p, c_bool, c_bool] exporttoclipcopy.restype = c_bool exporttoclipcopy(hsearch, csearch, filename, tfrom, tto, cameras, length, usepassword, pass
Read more