/* audioopmodule - Module to detect peak values in arrays */ #include "Python.h" #if SIZEOF_INT == 4 typedef int Py_Int32; typedef unsigned int Py_UInt32; #else #if SIZEOF_LONG == 4 typedef long Py_Int32; typedef unsigned long Py_UInt32; #else #error "No 4-byte integral type" #endif #endif #if defined(__CHAR_UNSIGNED__) #if defined(signed) /* This module currently does not work on systems where only unsigned characters are available. Take it out of Setup. Sorry. */ #endif #endif /* Code shamelessly stolen from sox, ** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */ #define MINLIN -32768 #define MAXLIN 32767 #define LINCLIP(x) do { if ( x < MINLIN ) x = MINLIN ; \ else if ( x > MAXLIN ) x = MAXLIN; \ } while ( 0 ) static unsigned char st_linear_to_ulaw(int sample); /* ** This macro converts from ulaw to 16 bit linear, faster. ** ** Jef Poskanzer ** 23 October 1989 ** ** Input: 8 bit ulaw sample ** Output: signed 16 bit linear sample */ #define st_ulaw_to_linear(ulawbyte) ulaw_table[ulawbyte] static int ulaw_table[256] = { -32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956, -23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764, -15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412, -11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316, -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, -1372, -1308, -1244, -1180, -1116, -1052, -988, -924, -876, -844, -812, -780, -748, -716, -684, -652, -620, -588, -556, -524, -492, -460, -428, -396, -372, -356, -340, -324, -308, -292, -276, -260, -244, -228, -212, -196, -180, -164, -148, -132, -120, -112, -104, -96, -88, -80, -72, -64, -56, -48, -40, -32, -24, -16, -8, 0, 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, 1372, 1308, 1244, 1180, 1116, 1052, 988, 924, 876, 844, 812, 780, 748, 716, 684, 652, 620, 588, 556, 524, 492, 460, 428, 396, 372, 356, 340, 324, 308, 292, 276, 260, 244, 228, 212, 196, 180, 164, 148, 132, 120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0 }; /* #define ZEROTRAP */ /* turn on the trap as per the MIL-STD */ #define BIAS 0x84 /* define the add-in bias for 16 bit samples */ #define CLIP 32635 static unsigned char st_linear_to_ulaw(int sample) { static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7}; int sign, exponent, mantissa; unsigned char ulawbyte; /* Get the sample into sign-magnitude. */ sign = (sample >> 8) & 0x80; /* set aside the sign */ if ( sign != 0 ) sample = -sample; /* get magnitude */ if ( sample > CLIP ) sample = CLIP; /* clip the magnitude */ /* Convert from 16 bit linear to ulaw. */ sample = sample + BIAS; exponent = exp_lut[( sample >> 7 ) & 0xFF]; mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F; ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa ); #ifdef ZEROTRAP if ( ulawbyte == 0 ) ulawbyte = 0x02; /* optional CCITT trap */ #endif return ulawbyte; } /* End of code taken from sox */ /* Intel ADPCM step variation table */ static int indexTable[16] = { -1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8, }; static int stepsizeTable[89] = { 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 }; #define CHARP(cp, i) ((signed char *)(cp+i)) #define SHORTP(cp, i) ((short *)(cp+i)) #define LONGP(cp, i) ((Py_Int32 *)(cp+i)) static PyObject *AudioopError; static PyObject * audioop_getsample(PyObject *self, PyObject *args) { signed char *cp; int len, size, val = 0; int i; if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &size, &i) ) return 0; if ( size != 1 && size != 2 && size != 4 ) { PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); return 0; } if ( i < 0 || i >= len/size ) { PyErr_SetString(AudioopError, "Index out of range"); return 0; } if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i*2); else if ( size == 4 ) val = (int)*LONGP(cp, i*4); return PyInt_FromLong(val); } static PyObject * audioop_max(PyObject *self, PyObject *args) { signed char *cp; int len, size, val = 0; int i; int max = 0; 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; } for ( i=0; i max ) max = val; } return PyInt_FromLong(max); } static PyObject * audioop_minmax(PyObject *self, PyObject *args) { signed char *cp; int len, size, val = 0; int i; int min = 0x7fffffff, max = -0x7fffffff; if (!PyArg_Parse(args, "(s#i)", &cp, &len, &size)) return NULL; if (size != 1 && size != 2 && size != 4) { PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); return NULL; } 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 (val > max) max = val; if (val < min) min = val; } return Py_BuildValue("(ii)", min, max); } static PyObject * audioop_avg(PyObject *self, PyObject *args) { signed char *cp; int len, size, val = 0; int i; double avg = 0.0; 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; } for ( i=0; i n, and let all sums be over i from 0 to n-1. ** ** Now, for each j in {0..N-n} we compute a factor fj so that -fj*R matches A ** as good as possible, i.e. sum( (A[j+i]+fj*R[i])^2 ) is minimal. This ** equation gives fj = sum( A[j+i]R[i] ) / sum(R[i]^2). ** ** Next, we compute the relative distance between the original signal and ** the modified signal and minimize that over j: ** vj = sum( (A[j+i]-fj*R[i])^2 ) / sum( A[j+i]^2 ) => ** vj = ( sum(A[j+i]^2)*sum(R[i]^2) - sum(A[j+i]R[i])^2 ) / sum( A[j+i]^2 ) ** ** In the code variables correspond as follows: ** cp1 A ** cp2 R ** len1 N ** len2 n ** aj_m1 A[j-1] ** aj_lm1 A[j+n-1] ** sum_ri_2 sum(R[i]^2) ** sum_aij_2 sum(A[i+j]^2) ** sum_aij_ri sum(A[i+j]R[i]) ** ** sum_ri is calculated once, sum_aij_2 is updated each step and sum_aij_ri ** is completely recalculated each step. */ static PyObject * audioop_findfit(PyObject *self, PyObject *args) { short *cp1, *cp2; int len1, len2; int j, best_j; double aj_m1, aj_lm1; double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor; if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &cp2, &len2) ) return 0; if ( len1 & 1 || len2 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } len1 >>= 1; len2 >>= 1; if ( len1 < len2 ) { PyErr_SetString(AudioopError, "First sample should be longer"); return 0; } sum_ri_2 = _sum2(cp2, cp2, len2); sum_aij_2 = _sum2(cp1, cp1, len2); sum_aij_ri = _sum2(cp1, cp2, len2); result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2; best_result = result; best_j = 0; j = 0; for ( j=1; j<=len1-len2; j++) { aj_m1 = (double)cp1[j-1]; aj_lm1 = (double)cp1[j+len2-1]; sum_aij_2 = sum_aij_2 + aj_lm1*aj_lm1 - aj_m1*aj_m1; sum_aij_ri = _sum2(cp1+j, cp2, len2); result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2; if ( result < best_result ) { best_result = result; best_j = j; } } factor = _sum2(cp1+best_j, cp2, len2) / sum_ri_2; return Py_BuildValue("(if)", best_j, factor); } /* ** findfactor finds a factor f so that the energy in A-fB is minimal. ** See the comment for findfit for details. */ static PyObject * audioop_findfactor(PyObject *self, PyObject *args) { short *cp1, *cp2; int len1, len2; double sum_ri_2, sum_aij_ri, result; if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &cp2, &len2) ) return 0; if ( len1 & 1 || len2 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } if ( len1 != len2 ) { PyErr_SetString(AudioopError, "Samples should be same size"); return 0; } len2 >>= 1; sum_ri_2 = _sum2(cp2, cp2, len2); sum_aij_ri = _sum2(cp1, cp2, len2); result = sum_aij_ri / sum_ri_2; return PyFloat_FromDouble(result); } /* ** findmax returns the index of the n-sized segment of the input sample ** that contains the most energy. */ static PyObject * audioop_findmax(PyObject *self, PyObject *args) { short *cp1; int len1, len2; int j, best_j; double aj_m1, aj_lm1; double result, best_result; if ( !PyArg_Parse(args, "(s#i)", &cp1, &len1, &len2) ) return 0; if ( len1 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } len1 >>= 1; if ( len1 < len2 ) { PyErr_SetString(AudioopError, "Input sample should be longer"); return 0; } result = _sum2(cp1, cp1, len2); best_result = result; best_j = 0; j = 0; for ( j=1; j<=len1-len2; j++) { aj_m1 = (double)cp1[j-1]; aj_lm1 = (double)cp1[j+len2-1]; result = result + aj_lm1*aj_lm1 - aj_m1*aj_m1; if ( result > best_result ) { best_result = result; best_j = j; } } return PyInt_FromLong(best_j); } static PyObject * audioop_avgpp(PyObject *self, PyObject *args) { signed char *cp; int len, size, val = 0, prevval = 0, prevextremevalid = 0, prevextreme = 0; int i; double avg = 0.0; int diff, prevdiff, extremediff, nextreme = 0; 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 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> 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); if (samps == NULL) goto exit; 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); if (m == NULL) return; d = PyModule_GetDict(m); AudioopError = PyErr_NewException("audioop.error", NULL, NULL); if (AudioopError != NULL) PyDict_SetItemString(d,"error",AudioopError); }