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1381 lines
38 KiB
1381 lines
38 KiB
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/* audioopmodule - Module to detect peak values in arrays */ |
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#include "Python.h" |
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#if SIZEOF_INT == 4 |
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typedef int Py_Int32; |
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typedef unsigned int Py_UInt32; |
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#else |
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#if SIZEOF_LONG == 4 |
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typedef long Py_Int32; |
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typedef unsigned long Py_UInt32; |
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#else |
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#error "No 4-byte integral type" |
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#endif |
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#endif |
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#if defined(__CHAR_UNSIGNED__) |
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#if defined(signed) |
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/* This module currently does not work on systems where only unsigned |
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characters are available. Take it out of Setup. Sorry. */ |
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#endif |
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#endif |
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/* Code shamelessly stolen from sox, |
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** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */ |
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#define MINLIN -32768 |
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#define MAXLIN 32767 |
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#define LINCLIP(x) do { if ( x < MINLIN ) x = MINLIN ; \ |
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else if ( x > MAXLIN ) x = MAXLIN; \ |
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} while ( 0 ) |
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static unsigned char st_linear_to_ulaw(int sample); |
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/* |
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** This macro converts from ulaw to 16 bit linear, faster. |
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** |
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** Jef Poskanzer |
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** 23 October 1989 |
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** |
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** Input: 8 bit ulaw sample |
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** Output: signed 16 bit linear sample |
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*/ |
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#define st_ulaw_to_linear(ulawbyte) ulaw_table[ulawbyte] |
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static int ulaw_table[256] = { |
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-32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956, |
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-23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764, |
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-15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412, |
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-11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316, |
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-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, |
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-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, |
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-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, |
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-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, |
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-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, |
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-1372, -1308, -1244, -1180, -1116, -1052, -988, -924, |
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-876, -844, -812, -780, -748, -716, -684, -652, |
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-620, -588, -556, -524, -492, -460, -428, -396, |
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-372, -356, -340, -324, -308, -292, -276, -260, |
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-244, -228, -212, -196, -180, -164, -148, -132, |
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-120, -112, -104, -96, -88, -80, -72, -64, |
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-56, -48, -40, -32, -24, -16, -8, 0, |
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32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, |
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23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, |
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15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, |
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11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, |
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7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, |
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5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, |
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3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, |
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2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, |
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1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, |
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1372, 1308, 1244, 1180, 1116, 1052, 988, 924, |
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876, 844, 812, 780, 748, 716, 684, 652, |
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620, 588, 556, 524, 492, 460, 428, 396, |
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372, 356, 340, 324, 308, 292, 276, 260, |
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244, 228, 212, 196, 180, 164, 148, 132, |
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120, 112, 104, 96, 88, 80, 72, 64, |
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56, 48, 40, 32, 24, 16, 8, 0 }; |
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/* #define ZEROTRAP */ /* turn on the trap as per the MIL-STD */ |
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#define BIAS 0x84 /* define the add-in bias for 16 bit samples */ |
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#define CLIP 32635 |
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static unsigned char |
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st_linear_to_ulaw(int sample) |
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{ |
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static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3, |
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4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, |
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5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, |
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5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, |
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, |
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, |
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, |
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, |
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7}; |
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int sign, exponent, mantissa; |
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unsigned char ulawbyte; |
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/* Get the sample into sign-magnitude. */ |
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sign = (sample >> 8) & 0x80; /* set aside the sign */ |
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if ( sign != 0 ) sample = -sample; /* get magnitude */ |
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if ( sample > CLIP ) sample = CLIP; /* clip the magnitude */ |
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/* Convert from 16 bit linear to ulaw. */ |
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sample = sample + BIAS; |
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exponent = exp_lut[( sample >> 7 ) & 0xFF]; |
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mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F; |
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ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa ); |
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#ifdef ZEROTRAP |
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if ( ulawbyte == 0 ) ulawbyte = 0x02; /* optional CCITT trap */ |
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#endif |
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return ulawbyte; |
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} |
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/* End of code taken from sox */ |
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/* Intel ADPCM step variation table */ |
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static int indexTable[16] = { |
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-1, -1, -1, -1, 2, 4, 6, 8, |
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-1, -1, -1, -1, 2, 4, 6, 8, |
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}; |
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static int stepsizeTable[89] = { |
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7, 8, 9, 10, 11, 12, 13, 14, 16, 17, |
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19, 21, 23, 25, 28, 31, 34, 37, 41, 45, |
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50, 55, 60, 66, 73, 80, 88, 97, 107, 118, |
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130, 143, 157, 173, 190, 209, 230, 253, 279, 307, |
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337, 371, 408, 449, 494, 544, 598, 658, 724, 796, |
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876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, |
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2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, |
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5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, |
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15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 |
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}; |
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#define CHARP(cp, i) ((signed char *)(cp+i)) |
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#define SHORTP(cp, i) ((short *)(cp+i)) |
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#define LONGP(cp, i) ((Py_Int32 *)(cp+i)) |
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static PyObject *AudioopError; |
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static PyObject * |
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audioop_getsample(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0; |
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int i; |
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if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &size, &i) ) |
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return 0; |
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if ( size != 1 && size != 2 && size != 4 ) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return 0; |
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} |
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if ( i < 0 || i >= len/size ) { |
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PyErr_SetString(AudioopError, "Index out of range"); |
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return 0; |
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} |
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if ( size == 1 ) val = (int)*CHARP(cp, i); |
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else if ( size == 2 ) val = (int)*SHORTP(cp, i*2); |
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else if ( size == 4 ) val = (int)*LONGP(cp, i*4); |
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return PyInt_FromLong(val); |
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} |
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static PyObject * |
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audioop_max(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0; |
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int i; |
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int max = 0; |
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if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
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return 0; |
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if ( size != 1 && size != 2 && size != 4 ) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return 0; |
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} |
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for ( i=0; i<len; i+= size) { |
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if ( size == 1 ) val = (int)*CHARP(cp, i); |
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else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
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else if ( size == 4 ) val = (int)*LONGP(cp, i); |
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if ( val < 0 ) val = (-val); |
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if ( val > max ) max = val; |
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} |
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return PyInt_FromLong(max); |
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} |
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static PyObject * |
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audioop_minmax(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0; |
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int i; |
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int min = 0x7fffffff, max = -0x7fffffff; |
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if (!PyArg_Parse(args, "(s#i)", &cp, &len, &size)) |
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return NULL; |
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if (size != 1 && size != 2 && size != 4) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return NULL; |
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} |
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for (i = 0; i < len; i += size) { |
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if (size == 1) val = (int) *CHARP(cp, i); |
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else if (size == 2) val = (int) *SHORTP(cp, i); |
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else if (size == 4) val = (int) *LONGP(cp, i); |
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if (val > max) max = val; |
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if (val < min) min = val; |
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} |
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return Py_BuildValue("(ii)", min, max); |
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} |
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static PyObject * |
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audioop_avg(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0; |
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int i; |
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double avg = 0.0; |
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if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
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return 0; |
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if ( size != 1 && size != 2 && size != 4 ) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return 0; |
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} |
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for ( i=0; i<len; i+= size) { |
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if ( size == 1 ) val = (int)*CHARP(cp, i); |
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else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
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else if ( size == 4 ) val = (int)*LONGP(cp, i); |
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avg += val; |
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} |
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if ( len == 0 ) |
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val = 0; |
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else |
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val = (int)(avg / (double)(len/size)); |
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return PyInt_FromLong(val); |
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} |
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static PyObject * |
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audioop_rms(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0; |
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int i; |
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double sum_squares = 0.0; |
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if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
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return 0; |
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if ( size != 1 && size != 2 && size != 4 ) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return 0; |
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} |
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for ( i=0; i<len; i+= size) { |
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if ( size == 1 ) val = (int)*CHARP(cp, i); |
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else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
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else if ( size == 4 ) val = (int)*LONGP(cp, i); |
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sum_squares += (double)val*(double)val; |
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} |
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if ( len == 0 ) |
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val = 0; |
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else |
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val = (int)sqrt(sum_squares / (double)(len/size)); |
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return PyInt_FromLong(val); |
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} |
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static double _sum2(short *a, short *b, int len) |
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{ |
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int i; |
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double sum = 0.0; |
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for( i=0; i<len; i++) { |
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sum = sum + (double)a[i]*(double)b[i]; |
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} |
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return sum; |
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} |
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/* |
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** Findfit tries to locate a sample within another sample. Its main use |
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** is in echo-cancellation (to find the feedback of the output signal in |
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** the input signal). |
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** The method used is as follows: |
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** |
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** let R be the reference signal (length n) and A the input signal (length N) |
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** with N > n, and let all sums be over i from 0 to n-1. |
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** |
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** Now, for each j in {0..N-n} we compute a factor fj so that -fj*R matches A |
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** as good as possible, i.e. sum( (A[j+i]+fj*R[i])^2 ) is minimal. This |
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** equation gives fj = sum( A[j+i]R[i] ) / sum(R[i]^2). |
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** |
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** Next, we compute the relative distance between the original signal and |
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** the modified signal and minimize that over j: |
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** vj = sum( (A[j+i]-fj*R[i])^2 ) / sum( A[j+i]^2 ) => |
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** vj = ( sum(A[j+i]^2)*sum(R[i]^2) - sum(A[j+i]R[i])^2 ) / sum( A[j+i]^2 ) |
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** |
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** In the code variables correspond as follows: |
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** cp1 A |
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** cp2 R |
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** len1 N |
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** len2 n |
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** aj_m1 A[j-1] |
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** aj_lm1 A[j+n-1] |
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** sum_ri_2 sum(R[i]^2) |
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** sum_aij_2 sum(A[i+j]^2) |
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** sum_aij_ri sum(A[i+j]R[i]) |
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** |
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** sum_ri is calculated once, sum_aij_2 is updated each step and sum_aij_ri |
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** is completely recalculated each step. |
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*/ |
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static PyObject * |
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audioop_findfit(PyObject *self, PyObject *args) |
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{ |
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short *cp1, *cp2; |
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int len1, len2; |
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int j, best_j; |
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double aj_m1, aj_lm1; |
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double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor; |
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if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &cp2, &len2) ) |
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return 0; |
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if ( len1 & 1 || len2 & 1 ) { |
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PyErr_SetString(AudioopError, "Strings should be even-sized"); |
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return 0; |
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} |
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len1 >>= 1; |
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len2 >>= 1; |
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if ( len1 < len2 ) { |
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PyErr_SetString(AudioopError, "First sample should be longer"); |
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return 0; |
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} |
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sum_ri_2 = _sum2(cp2, cp2, len2); |
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sum_aij_2 = _sum2(cp1, cp1, len2); |
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sum_aij_ri = _sum2(cp1, cp2, len2); |
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result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2; |
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best_result = result; |
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best_j = 0; |
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j = 0; |
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for ( j=1; j<=len1-len2; j++) { |
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aj_m1 = (double)cp1[j-1]; |
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aj_lm1 = (double)cp1[j+len2-1]; |
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sum_aij_2 = sum_aij_2 + aj_lm1*aj_lm1 - aj_m1*aj_m1; |
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sum_aij_ri = _sum2(cp1+j, cp2, len2); |
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result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) |
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/ sum_aij_2; |
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if ( result < best_result ) { |
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best_result = result; |
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best_j = j; |
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} |
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} |
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factor = _sum2(cp1+best_j, cp2, len2) / sum_ri_2; |
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return Py_BuildValue("(if)", best_j, factor); |
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} |
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/* |
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** findfactor finds a factor f so that the energy in A-fB is minimal. |
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** See the comment for findfit for details. |
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*/ |
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static PyObject * |
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audioop_findfactor(PyObject *self, PyObject *args) |
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{ |
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short *cp1, *cp2; |
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int len1, len2; |
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double sum_ri_2, sum_aij_ri, result; |
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if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &cp2, &len2) ) |
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return 0; |
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if ( len1 & 1 || len2 & 1 ) { |
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PyErr_SetString(AudioopError, "Strings should be even-sized"); |
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return 0; |
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} |
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if ( len1 != len2 ) { |
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PyErr_SetString(AudioopError, "Samples should be same size"); |
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return 0; |
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} |
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len2 >>= 1; |
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sum_ri_2 = _sum2(cp2, cp2, len2); |
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sum_aij_ri = _sum2(cp1, cp2, len2); |
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|
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result = sum_aij_ri / sum_ri_2; |
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|
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return PyFloat_FromDouble(result); |
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} |
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|
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/* |
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** findmax returns the index of the n-sized segment of the input sample |
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** that contains the most energy. |
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*/ |
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static PyObject * |
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audioop_findmax(PyObject *self, PyObject *args) |
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{ |
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short *cp1; |
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int len1, len2; |
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int j, best_j; |
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double aj_m1, aj_lm1; |
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double result, best_result; |
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|
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if ( !PyArg_Parse(args, "(s#i)", &cp1, &len1, &len2) ) |
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return 0; |
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if ( len1 & 1 ) { |
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PyErr_SetString(AudioopError, "Strings should be even-sized"); |
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return 0; |
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} |
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len1 >>= 1; |
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|
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if ( len1 < len2 ) { |
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PyErr_SetString(AudioopError, "Input sample should be longer"); |
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return 0; |
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} |
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|
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result = _sum2(cp1, cp1, len2); |
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best_result = result; |
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best_j = 0; |
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j = 0; |
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for ( j=1; j<=len1-len2; j++) { |
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aj_m1 = (double)cp1[j-1]; |
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aj_lm1 = (double)cp1[j+len2-1]; |
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|
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result = result + aj_lm1*aj_lm1 - aj_m1*aj_m1; |
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|
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if ( result > best_result ) { |
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best_result = result; |
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best_j = j; |
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} |
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|
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} |
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|
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return PyInt_FromLong(best_j); |
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} |
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static PyObject * |
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audioop_avgpp(PyObject *self, PyObject *args) |
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{ |
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signed char *cp; |
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int len, size, val = 0, prevval = 0, prevextremevalid = 0, |
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prevextreme = 0; |
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int i; |
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double avg = 0.0; |
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int diff, prevdiff, extremediff, nextreme = 0; |
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|
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if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
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return 0; |
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if ( size != 1 && size != 2 && size != 4 ) { |
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PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
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return 0; |
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} |
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/* Compute first delta value ahead. Also automatically makes us |
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** skip the first extreme value |
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*/ |
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if ( size == 1 ) prevval = (int)*CHARP(cp, 0); |
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else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0); |
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else if ( size == 4 ) prevval = (int)*LONGP(cp, 0); |
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if ( size == 1 ) val = (int)*CHARP(cp, size); |
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else if ( size == 2 ) val = (int)*SHORTP(cp, size); |
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else if ( size == 4 ) val = (int)*LONGP(cp, size); |
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prevdiff = val - prevval; |
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|
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for ( i=size; i<len; i+= size) { |
|
if ( size == 1 ) val = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, i); |
|
diff = val - prevval; |
|
if ( diff*prevdiff < 0 ) { |
|
/* Derivative changed sign. Compute difference to last |
|
** extreme value and remember. |
|
*/ |
|
if ( prevextremevalid ) { |
|
extremediff = prevval - prevextreme; |
|
if ( extremediff < 0 ) |
|
extremediff = -extremediff; |
|
avg += extremediff; |
|
nextreme++; |
|
} |
|
prevextremevalid = 1; |
|
prevextreme = prevval; |
|
} |
|
prevval = val; |
|
if ( diff != 0 ) |
|
prevdiff = diff; |
|
} |
|
if ( nextreme == 0 ) |
|
val = 0; |
|
else |
|
val = (int)(avg / (double)nextreme); |
|
return PyInt_FromLong(val); |
|
} |
|
|
|
static PyObject * |
|
audioop_maxpp(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
int len, size, val = 0, prevval = 0, prevextremevalid = 0, |
|
prevextreme = 0; |
|
int i; |
|
int max = 0; |
|
int diff, prevdiff, extremediff; |
|
|
|
if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
|
return 0; |
|
if ( size != 1 && size != 2 && size != 4 ) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
/* Compute first delta value ahead. Also automatically makes us |
|
** skip the first extreme value |
|
*/ |
|
if ( size == 1 ) prevval = (int)*CHARP(cp, 0); |
|
else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0); |
|
else if ( size == 4 ) prevval = (int)*LONGP(cp, 0); |
|
if ( size == 1 ) val = (int)*CHARP(cp, size); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, size); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, size); |
|
prevdiff = val - prevval; |
|
|
|
for ( i=size; i<len; i+= size) { |
|
if ( size == 1 ) val = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, i); |
|
diff = val - prevval; |
|
if ( diff*prevdiff < 0 ) { |
|
/* Derivative changed sign. Compute difference to |
|
** last extreme value and remember. |
|
*/ |
|
if ( prevextremevalid ) { |
|
extremediff = prevval - prevextreme; |
|
if ( extremediff < 0 ) |
|
extremediff = -extremediff; |
|
if ( extremediff > max ) |
|
max = extremediff; |
|
} |
|
prevextremevalid = 1; |
|
prevextreme = prevval; |
|
} |
|
prevval = val; |
|
if ( diff != 0 ) |
|
prevdiff = diff; |
|
} |
|
return PyInt_FromLong(max); |
|
} |
|
|
|
static PyObject * |
|
audioop_cross(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
int len, size, val = 0; |
|
int i; |
|
int prevval, ncross; |
|
|
|
if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) ) |
|
return 0; |
|
if ( size != 1 && size != 2 && size != 4 ) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
ncross = -1; |
|
prevval = 17; /* Anything <> 0,1 */ |
|
for ( i=0; i<len; i+= size) { |
|
if ( size == 1 ) val = ((int)*CHARP(cp, i)) >> 7; |
|
else if ( size == 2 ) val = ((int)*SHORTP(cp, i)) >> 15; |
|
else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 31; |
|
val = val & 1; |
|
if ( val != prevval ) ncross++; |
|
prevval = val; |
|
} |
|
return PyInt_FromLong(ncross); |
|
} |
|
|
|
static PyObject * |
|
audioop_mul(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp, *ncp; |
|
int len, size, val = 0; |
|
double factor, fval, maxval; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#id)", &cp, &len, &size, &factor ) ) |
|
return 0; |
|
|
|
if ( size == 1 ) maxval = (double) 0x7f; |
|
else if ( size == 2 ) maxval = (double) 0x7fff; |
|
else if ( size == 4 ) maxval = (double) 0x7fffffff; |
|
else { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, i); |
|
fval = (double)val*factor; |
|
if ( fval > maxval ) fval = maxval; |
|
else if ( fval < -maxval ) fval = -maxval; |
|
val = (int)fval; |
|
if ( size == 1 ) *CHARP(ncp, i) = (signed char)val; |
|
else if ( size == 2 ) *SHORTP(ncp, i) = (short)val; |
|
else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)val; |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_tomono(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp, *ncp; |
|
int len, size, val1 = 0, val2 = 0; |
|
double fac1, fac2, fval, maxval; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#idd)", &cp, &len, &size, &fac1, &fac2 ) ) |
|
return 0; |
|
|
|
if ( size == 1 ) maxval = (double) 0x7f; |
|
else if ( size == 2 ) maxval = (double) 0x7fff; |
|
else if ( size == 4 ) maxval = (double) 0x7fffffff; |
|
else { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len/2); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
|
|
for ( i=0; i < len; i += size*2 ) { |
|
if ( size == 1 ) val1 = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val1 = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val1 = (int)*LONGP(cp, i); |
|
if ( size == 1 ) val2 = (int)*CHARP(cp, i+1); |
|
else if ( size == 2 ) val2 = (int)*SHORTP(cp, i+2); |
|
else if ( size == 4 ) val2 = (int)*LONGP(cp, i+4); |
|
fval = (double)val1*fac1 + (double)val2*fac2; |
|
if ( fval > maxval ) fval = maxval; |
|
else if ( fval < -maxval ) fval = -maxval; |
|
val1 = (int)fval; |
|
if ( size == 1 ) *CHARP(ncp, i/2) = (signed char)val1; |
|
else if ( size == 2 ) *SHORTP(ncp, i/2) = (short)val1; |
|
else if ( size == 4 ) *LONGP(ncp, i/2)= (Py_Int32)val1; |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_tostereo(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp, *ncp; |
|
int len, size, val1, val2, val = 0; |
|
double fac1, fac2, fval, maxval; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#idd)", &cp, &len, &size, &fac1, &fac2 ) ) |
|
return 0; |
|
|
|
if ( size == 1 ) maxval = (double) 0x7f; |
|
else if ( size == 2 ) maxval = (double) 0x7fff; |
|
else if ( size == 4 ) maxval = (double) 0x7fffffff; |
|
else { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len*2); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, i); |
|
|
|
fval = (double)val*fac1; |
|
if ( fval > maxval ) fval = maxval; |
|
else if ( fval < -maxval ) fval = -maxval; |
|
val1 = (int)fval; |
|
|
|
fval = (double)val*fac2; |
|
if ( fval > maxval ) fval = maxval; |
|
else if ( fval < -maxval ) fval = -maxval; |
|
val2 = (int)fval; |
|
|
|
if ( size == 1 ) *CHARP(ncp, i*2) = (signed char)val1; |
|
else if ( size == 2 ) *SHORTP(ncp, i*2) = (short)val1; |
|
else if ( size == 4 ) *LONGP(ncp, i*2) = (Py_Int32)val1; |
|
|
|
if ( size == 1 ) *CHARP(ncp, i*2+1) = (signed char)val2; |
|
else if ( size == 2 ) *SHORTP(ncp, i*2+2) = (short)val2; |
|
else if ( size == 4 ) *LONGP(ncp, i*2+4) = (Py_Int32)val2; |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_add(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp1, *cp2, *ncp; |
|
int len1, len2, size, val1 = 0, val2 = 0, maxval, newval; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#s#i)", |
|
&cp1, &len1, &cp2, &len2, &size ) ) |
|
return 0; |
|
|
|
if ( len1 != len2 ) { |
|
PyErr_SetString(AudioopError, "Lengths should be the same"); |
|
return 0; |
|
} |
|
|
|
if ( size == 1 ) maxval = 0x7f; |
|
else if ( size == 2 ) maxval = 0x7fff; |
|
else if ( size == 4 ) maxval = 0x7fffffff; |
|
else { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len1); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
for ( i=0; i < len1; i += size ) { |
|
if ( size == 1 ) val1 = (int)*CHARP(cp1, i); |
|
else if ( size == 2 ) val1 = (int)*SHORTP(cp1, i); |
|
else if ( size == 4 ) val1 = (int)*LONGP(cp1, i); |
|
|
|
if ( size == 1 ) val2 = (int)*CHARP(cp2, i); |
|
else if ( size == 2 ) val2 = (int)*SHORTP(cp2, i); |
|
else if ( size == 4 ) val2 = (int)*LONGP(cp2, i); |
|
|
|
newval = val1 + val2; |
|
/* truncate in case of overflow */ |
|
if (newval > maxval) newval = maxval; |
|
else if (newval < -maxval) newval = -maxval; |
|
else if (size == 4 && (newval^val1) < 0 && (newval^val2) < 0) |
|
newval = val1 > 0 ? maxval : - maxval; |
|
|
|
if ( size == 1 ) *CHARP(ncp, i) = (signed char)newval; |
|
else if ( size == 2 ) *SHORTP(ncp, i) = (short)newval; |
|
else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)newval; |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_bias(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp, *ncp; |
|
int len, size, val = 0; |
|
PyObject *rv; |
|
int i; |
|
int bias; |
|
|
|
if ( !PyArg_Parse(args, "(s#ii)", |
|
&cp, &len, &size , &bias) ) |
|
return 0; |
|
|
|
if ( size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = (int)*CHARP(cp, i); |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = (int)*LONGP(cp, i); |
|
|
|
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val+bias); |
|
else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val+bias); |
|
else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val+bias); |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_reverse(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
unsigned char *ncp; |
|
int len, size, val = 0; |
|
PyObject *rv; |
|
int i, j; |
|
|
|
if ( !PyArg_Parse(args, "(s#i)", |
|
&cp, &len, &size) ) |
|
return 0; |
|
|
|
if ( size != 1 && size != 2 && size != 4 ) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (unsigned char *)PyString_AsString(rv); |
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16; |
|
|
|
j = len - i - size; |
|
|
|
if ( size == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8); |
|
else if ( size == 2 ) *SHORTP(ncp, j) = (short)(val); |
|
else if ( size == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16); |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_lin2lin(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
unsigned char *ncp; |
|
int len, size, size2, val = 0; |
|
PyObject *rv; |
|
int i, j; |
|
|
|
if ( !PyArg_Parse(args, "(s#ii)", |
|
&cp, &len, &size, &size2) ) |
|
return 0; |
|
|
|
if ( (size != 1 && size != 2 && size != 4) || |
|
(size2 != 1 && size2 != 2 && size2 != 4)) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, (len/size)*size2); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (unsigned char *)PyString_AsString(rv); |
|
|
|
for ( i=0, j=0; i < len; i += size, j += size2 ) { |
|
if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16; |
|
|
|
if ( size2 == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8); |
|
else if ( size2 == 2 ) *SHORTP(ncp, j) = (short)(val); |
|
else if ( size2 == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16); |
|
} |
|
return rv; |
|
} |
|
|
|
static int |
|
gcd(int a, int b) |
|
{ |
|
while (b > 0) { |
|
int tmp = a % b; |
|
a = b; |
|
b = tmp; |
|
} |
|
return a; |
|
} |
|
|
|
static PyObject * |
|
audioop_ratecv(PyObject *self, PyObject *args) |
|
{ |
|
char *cp, *ncp; |
|
int len, size, nchannels, inrate, outrate, weightA, weightB; |
|
int chan, d, *prev_i, *cur_i, cur_o; |
|
PyObject *state, *samps, *str, *rv = NULL; |
|
int bytes_per_frame; |
|
|
|
weightA = 1; |
|
weightB = 0; |
|
if (!PyArg_ParseTuple(args, "s#iiiiO|ii:ratecv", &cp, &len, &size, &nchannels, |
|
&inrate, &outrate, &state, &weightA, &weightB)) |
|
return NULL; |
|
if (size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return NULL; |
|
} |
|
if (nchannels < 1) { |
|
PyErr_SetString(AudioopError, "# of channels should be >= 1"); |
|
return NULL; |
|
} |
|
bytes_per_frame = size * nchannels; |
|
if (bytes_per_frame / nchannels != size) { |
|
/* This overflow test is rigorously correct because |
|
both multiplicands are >= 1. Use the argument names |
|
from the docs for the error msg. */ |
|
PyErr_SetString(PyExc_OverflowError, |
|
"width * nchannels too big for a C int"); |
|
return NULL; |
|
} |
|
if (weightA < 1 || weightB < 0) { |
|
PyErr_SetString(AudioopError, |
|
"weightA should be >= 1, weightB should be >= 0"); |
|
return NULL; |
|
} |
|
if (len % bytes_per_frame != 0) { |
|
PyErr_SetString(AudioopError, "not a whole number of frames"); |
|
return NULL; |
|
} |
|
if (inrate <= 0 || outrate <= 0) { |
|
PyErr_SetString(AudioopError, "sampling rate not > 0"); |
|
return NULL; |
|
} |
|
/* divide inrate and outrate by their greatest common divisor */ |
|
d = gcd(inrate, outrate); |
|
inrate /= d; |
|
outrate /= d; |
|
|
|
prev_i = (int *) malloc(nchannels * sizeof(int)); |
|
cur_i = (int *) malloc(nchannels * sizeof(int)); |
|
if (prev_i == NULL || cur_i == NULL) { |
|
(void) PyErr_NoMemory(); |
|
goto exit; |
|
} |
|
|
|
len /= bytes_per_frame; /* # of frames */ |
|
|
|
if (state == Py_None) { |
|
d = -outrate; |
|
for (chan = 0; chan < nchannels; chan++) |
|
prev_i[chan] = cur_i[chan] = 0; |
|
} |
|
else { |
|
if (!PyArg_ParseTuple(state, |
|
"iO!;audioop.ratecv: illegal state argument", |
|
&d, &PyTuple_Type, &samps)) |
|
goto exit; |
|
if (PyTuple_Size(samps) != nchannels) { |
|
PyErr_SetString(AudioopError, |
|
"illegal state argument"); |
|
goto exit; |
|
} |
|
for (chan = 0; chan < nchannels; chan++) { |
|
if (!PyArg_ParseTuple(PyTuple_GetItem(samps, chan), |
|
"ii:ratecv",&prev_i[chan],&cur_i[chan])) |
|
goto exit; |
|
} |
|
} |
|
|
|
/* str <- Space for the output buffer. */ |
|
{ |
|
/* There are len input frames, so we need (mathematically) |
|
ceiling(len*outrate/inrate) output frames, and each frame |
|
requires bytes_per_frame bytes. Computing this |
|
without spurious overflow is the challenge; we can |
|
settle for a reasonable upper bound, though. */ |
|
int ceiling; /* the number of output frames */ |
|
int nbytes; /* the number of output bytes needed */ |
|
int q = len / inrate; |
|
/* Now len = q * inrate + r exactly (with r = len % inrate), |
|
and this is less than q * inrate + inrate = (q+1)*inrate. |
|
So a reasonable upper bound on len*outrate/inrate is |
|
((q+1)*inrate)*outrate/inrate = |
|
(q+1)*outrate. |
|
*/ |
|
ceiling = (q+1) * outrate; |
|
nbytes = ceiling * bytes_per_frame; |
|
/* See whether anything overflowed; if not, get the space. */ |
|
if (q+1 < 0 || |
|
ceiling / outrate != q+1 || |
|
nbytes / bytes_per_frame != ceiling) |
|
str = NULL; |
|
else |
|
str = PyString_FromStringAndSize(NULL, nbytes); |
|
|
|
if (str == NULL) { |
|
PyErr_SetString(PyExc_MemoryError, |
|
"not enough memory for output buffer"); |
|
goto exit; |
|
} |
|
} |
|
ncp = PyString_AsString(str); |
|
|
|
for (;;) { |
|
while (d < 0) { |
|
if (len == 0) { |
|
samps = PyTuple_New(nchannels); |
|
for (chan = 0; chan < nchannels; chan++) |
|
PyTuple_SetItem(samps, chan, |
|
Py_BuildValue("(ii)", |
|
prev_i[chan], |
|
cur_i[chan])); |
|
if (PyErr_Occurred()) |
|
goto exit; |
|
len = ncp - PyString_AsString(str); |
|
if (len == 0) { |
|
/*don't want to resize to zero length*/ |
|
rv = PyString_FromStringAndSize("", 0); |
|
Py_DECREF(str); |
|
str = rv; |
|
} else if (_PyString_Resize(&str, len) < 0) |
|
goto exit; |
|
rv = Py_BuildValue("(O(iO))", str, d, samps); |
|
Py_DECREF(samps); |
|
Py_DECREF(str); |
|
goto exit; /* return rv */ |
|
} |
|
for (chan = 0; chan < nchannels; chan++) { |
|
prev_i[chan] = cur_i[chan]; |
|
if (size == 1) |
|
cur_i[chan] = ((int)*CHARP(cp, 0)) << 8; |
|
else if (size == 2) |
|
cur_i[chan] = (int)*SHORTP(cp, 0); |
|
else if (size == 4) |
|
cur_i[chan] = ((int)*LONGP(cp, 0)) >> 16; |
|
cp += size; |
|
/* implements a simple digital filter */ |
|
cur_i[chan] = |
|
(weightA * cur_i[chan] + |
|
weightB * prev_i[chan]) / |
|
(weightA + weightB); |
|
} |
|
len--; |
|
d += outrate; |
|
} |
|
while (d >= 0) { |
|
for (chan = 0; chan < nchannels; chan++) { |
|
cur_o = (prev_i[chan] * d + |
|
cur_i[chan] * (outrate - d)) / |
|
outrate; |
|
if (size == 1) |
|
*CHARP(ncp, 0) = (signed char)(cur_o >> 8); |
|
else if (size == 2) |
|
*SHORTP(ncp, 0) = (short)(cur_o); |
|
else if (size == 4) |
|
*LONGP(ncp, 0) = (Py_Int32)(cur_o<<16); |
|
ncp += size; |
|
} |
|
d -= inrate; |
|
} |
|
} |
|
exit: |
|
if (prev_i != NULL) |
|
free(prev_i); |
|
if (cur_i != NULL) |
|
free(cur_i); |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_lin2ulaw(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
unsigned char *ncp; |
|
int len, size, val = 0; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#i)", |
|
&cp, &len, &size) ) |
|
return 0; |
|
|
|
if ( size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len/size); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (unsigned char *)PyString_AsString(rv); |
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16; |
|
|
|
*ncp++ = st_linear_to_ulaw(val); |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_ulaw2lin(PyObject *self, PyObject *args) |
|
{ |
|
unsigned char *cp; |
|
unsigned char cval; |
|
signed char *ncp; |
|
int len, size, val; |
|
PyObject *rv; |
|
int i; |
|
|
|
if ( !PyArg_Parse(args, "(s#i)", |
|
&cp, &len, &size) ) |
|
return 0; |
|
|
|
if ( size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
rv = PyString_FromStringAndSize(NULL, len*size); |
|
if ( rv == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(rv); |
|
|
|
for ( i=0; i < len*size; i += size ) { |
|
cval = *cp++; |
|
val = st_ulaw_to_linear(cval); |
|
|
|
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val >> 8); |
|
else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val); |
|
else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val<<16); |
|
} |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_lin2adpcm(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
signed char *ncp; |
|
int len, size, val = 0, step, valpred, delta, |
|
index, sign, vpdiff, diff; |
|
PyObject *rv, *state, *str; |
|
int i, outputbuffer = 0, bufferstep; |
|
|
|
if ( !PyArg_Parse(args, "(s#iO)", |
|
&cp, &len, &size, &state) ) |
|
return 0; |
|
|
|
|
|
if ( size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
str = PyString_FromStringAndSize(NULL, len/(size*2)); |
|
if ( str == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(str); |
|
|
|
/* Decode state, should have (value, step) */ |
|
if ( state == Py_None ) { |
|
/* First time, it seems. Set defaults */ |
|
valpred = 0; |
|
step = 7; |
|
index = 0; |
|
} else if ( !PyArg_Parse(state, "(ii)", &valpred, &index) ) |
|
return 0; |
|
|
|
step = stepsizeTable[index]; |
|
bufferstep = 1; |
|
|
|
for ( i=0; i < len; i += size ) { |
|
if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; |
|
else if ( size == 2 ) val = (int)*SHORTP(cp, i); |
|
else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16; |
|
|
|
/* Step 1 - compute difference with previous value */ |
|
diff = val - valpred; |
|
sign = (diff < 0) ? 8 : 0; |
|
if ( sign ) diff = (-diff); |
|
|
|
/* Step 2 - Divide and clamp */ |
|
/* Note: |
|
** This code *approximately* computes: |
|
** delta = diff*4/step; |
|
** vpdiff = (delta+0.5)*step/4; |
|
** but in shift step bits are dropped. The net result of this |
|
** is that even if you have fast mul/div hardware you cannot |
|
** put it to good use since the fixup would be too expensive. |
|
*/ |
|
delta = 0; |
|
vpdiff = (step >> 3); |
|
|
|
if ( diff >= step ) { |
|
delta = 4; |
|
diff -= step; |
|
vpdiff += step; |
|
} |
|
step >>= 1; |
|
if ( diff >= step ) { |
|
delta |= 2; |
|
diff -= step; |
|
vpdiff += step; |
|
} |
|
step >>= 1; |
|
if ( diff >= step ) { |
|
delta |= 1; |
|
vpdiff += step; |
|
} |
|
|
|
/* Step 3 - Update previous value */ |
|
if ( sign ) |
|
valpred -= vpdiff; |
|
else |
|
valpred += vpdiff; |
|
|
|
/* Step 4 - Clamp previous value to 16 bits */ |
|
if ( valpred > 32767 ) |
|
valpred = 32767; |
|
else if ( valpred < -32768 ) |
|
valpred = -32768; |
|
|
|
/* Step 5 - Assemble value, update index and step values */ |
|
delta |= sign; |
|
|
|
index += indexTable[delta]; |
|
if ( index < 0 ) index = 0; |
|
if ( index > 88 ) index = 88; |
|
step = stepsizeTable[index]; |
|
|
|
/* Step 6 - Output value */ |
|
if ( bufferstep ) { |
|
outputbuffer = (delta << 4) & 0xf0; |
|
} else { |
|
*ncp++ = (delta & 0x0f) | outputbuffer; |
|
} |
|
bufferstep = !bufferstep; |
|
} |
|
rv = Py_BuildValue("(O(ii))", str, valpred, index); |
|
Py_DECREF(str); |
|
return rv; |
|
} |
|
|
|
static PyObject * |
|
audioop_adpcm2lin(PyObject *self, PyObject *args) |
|
{ |
|
signed char *cp; |
|
signed char *ncp; |
|
int len, size, valpred, step, delta, index, sign, vpdiff; |
|
PyObject *rv, *str, *state; |
|
int i, inputbuffer = 0, bufferstep; |
|
|
|
if ( !PyArg_Parse(args, "(s#iO)", |
|
&cp, &len, &size, &state) ) |
|
return 0; |
|
|
|
if ( size != 1 && size != 2 && size != 4) { |
|
PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); |
|
return 0; |
|
} |
|
|
|
/* Decode state, should have (value, step) */ |
|
if ( state == Py_None ) { |
|
/* First time, it seems. Set defaults */ |
|
valpred = 0; |
|
step = 7; |
|
index = 0; |
|
} else if ( !PyArg_Parse(state, "(ii)", &valpred, &index) ) |
|
return 0; |
|
|
|
str = PyString_FromStringAndSize(NULL, len*size*2); |
|
if ( str == 0 ) |
|
return 0; |
|
ncp = (signed char *)PyString_AsString(str); |
|
|
|
step = stepsizeTable[index]; |
|
bufferstep = 0; |
|
|
|
for ( i=0; i < len*size*2; i += size ) { |
|
/* Step 1 - get the delta value and compute next index */ |
|
if ( bufferstep ) { |
|
delta = inputbuffer & 0xf; |
|
} else { |
|
inputbuffer = *cp++; |
|
delta = (inputbuffer >> 4) & 0xf; |
|
} |
|
|
|
bufferstep = !bufferstep; |
|
|
|
/* Step 2 - Find new index value (for later) */ |
|
index += indexTable[delta]; |
|
if ( index < 0 ) index = 0; |
|
if ( index > 88 ) index = 88; |
|
|
|
/* Step 3 - Separate sign and magnitude */ |
|
sign = delta & 8; |
|
delta = delta & 7; |
|
|
|
/* Step 4 - Compute difference and new predicted value */ |
|
/* |
|
** Computes 'vpdiff = (delta+0.5)*step/4', but see comment |
|
** in adpcm_coder. |
|
*/ |
|
vpdiff = step >> 3; |
|
if ( delta & 4 ) vpdiff += step; |
|
if ( delta & 2 ) vpdiff += step>>1; |
|
if ( delta & 1 ) vpdiff += step>>2; |
|
|
|
if ( sign ) |
|
valpred -= vpdiff; |
|
else |
|
valpred += vpdiff; |
|
|
|
/* Step 5 - clamp output value */ |
|
if ( valpred > 32767 ) |
|
valpred = 32767; |
|
else if ( valpred < -32768 ) |
|
valpred = -32768; |
|
|
|
/* Step 6 - Update step value */ |
|
step = stepsizeTable[index]; |
|
|
|
/* Step 6 - Output value */ |
|
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(valpred >> 8); |
|
else if ( size == 2 ) *SHORTP(ncp, i) = (short)(valpred); |
|
else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(valpred<<16); |
|
} |
|
|
|
rv = Py_BuildValue("(O(ii))", str, valpred, index); |
|
Py_DECREF(str); |
|
return rv; |
|
} |
|
|
|
static PyMethodDef audioop_methods[] = { |
|
{ "max", audioop_max, METH_OLDARGS }, |
|
{ "minmax", audioop_minmax, METH_OLDARGS }, |
|
{ "avg", audioop_avg, METH_OLDARGS }, |
|
{ "maxpp", audioop_maxpp, METH_OLDARGS }, |
|
{ "avgpp", audioop_avgpp, METH_OLDARGS }, |
|
{ "rms", audioop_rms, METH_OLDARGS }, |
|
{ "findfit", audioop_findfit, METH_OLDARGS }, |
|
{ "findmax", audioop_findmax, METH_OLDARGS }, |
|
{ "findfactor", audioop_findfactor, METH_OLDARGS }, |
|
{ "cross", audioop_cross, METH_OLDARGS }, |
|
{ "mul", audioop_mul, METH_OLDARGS }, |
|
{ "add", audioop_add, METH_OLDARGS }, |
|
{ "bias", audioop_bias, METH_OLDARGS }, |
|
{ "ulaw2lin", audioop_ulaw2lin, METH_OLDARGS }, |
|
{ "lin2ulaw", audioop_lin2ulaw, METH_OLDARGS }, |
|
{ "lin2lin", audioop_lin2lin, METH_OLDARGS }, |
|
{ "adpcm2lin", audioop_adpcm2lin, METH_OLDARGS }, |
|
{ "lin2adpcm", audioop_lin2adpcm, METH_OLDARGS }, |
|
{ "tomono", audioop_tomono, METH_OLDARGS }, |
|
{ "tostereo", audioop_tostereo, METH_OLDARGS }, |
|
{ "getsample", audioop_getsample, METH_OLDARGS }, |
|
{ "reverse", audioop_reverse, METH_OLDARGS }, |
|
{ "ratecv", audioop_ratecv, METH_VARARGS }, |
|
{ 0, 0 } |
|
}; |
|
|
|
PyMODINIT_FUNC |
|
initaudioop(void) |
|
{ |
|
PyObject *m, *d; |
|
m = Py_InitModule("audioop", audioop_methods); |
|
d = PyModule_GetDict(m); |
|
AudioopError = PyErr_NewException("audioop.error", NULL, NULL); |
|
if (AudioopError != NULL) |
|
PyDict_SetItemString(d,"error",AudioopError); |
|
}
|
|
|