from cffi import FFI ffi = FFI() ffi.cdef(""" typedef short PyInt16; int ratecv(char* rv, char* cp, size_t len, int size, int nchannels, int inrate, int outrate, int* state_d, int* prev_i, int* cur_i, int weightA, int weightB); void tostereo(char* rv, char* cp, size_t len, int size, double fac1, double fac2); void add(char* rv, char* cp1, char* cp2, size_t len1, int size); /* 2's complement (14-bit range) */ unsigned char st_14linear2ulaw(PyInt16 pcm_val); PyInt16 st_ulaw2linear16(unsigned char); /* 2's complement (13-bit range) */ unsigned char st_linear2alaw(PyInt16 pcm_val); PyInt16 st_alaw2linear16(unsigned char); void lin2adcpm(unsigned char* rv, unsigned char* cp, size_t len, size_t size, int* state); void adcpm2lin(unsigned char* rv, unsigned char* cp, size_t len, size_t size, int* state); """) # This code is directly copied from CPython file: Modules/audioop.c _AUDIOOP_C_MODULE = r""" typedef short PyInt16; typedef int Py_Int32; /* Code shamelessly stolen from sox, 12.17.7, g711.c ** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */ /* From g711.c: * * December 30, 1994: * Functions linear2alaw, linear2ulaw have been updated to correctly * convert unquantized 16 bit values. * Tables for direct u- to A-law and A- to u-law conversions have been * corrected. * Borge Lindberg, Center for PersonKommunikation, Aalborg University. * bli@cpk.auc.dk * */ #define BIAS 0x84 /* define the add-in bias for 16 bit samples */ #define CLIP 32635 #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */ #define QUANT_MASK (0xf) /* Quantization field mask. */ #define SEG_SHIFT (4) /* Left shift for segment number. */ #define SEG_MASK (0x70) /* Segment field mask. */ static PyInt16 seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF}; static PyInt16 seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF}; static PyInt16 search(PyInt16 val, PyInt16 *table, int size) { int i; for (i = 0; i < size; i++) { if (val <= *table++) return (i); } return (size); } #define st_ulaw2linear16(uc) (_st_ulaw2linear16[uc]) #define st_alaw2linear16(uc) (_st_alaw2linear16[uc]) static PyInt16 _st_ulaw2linear16[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 }; /* * linear2ulaw() accepts a 14-bit signed integer and encodes it as u-law data * stored in a unsigned char. This function should only be called with * the data shifted such that it only contains information in the lower * 14-bits. * * In order to simplify the encoding process, the original linear magnitude * is biased by adding 33 which shifts the encoding range from (0 - 8158) to * (33 - 8191). The result can be seen in the following encoding table: * * Biased Linear Input Code Compressed Code * ------------------------ --------------- * 00000001wxyza 000wxyz * 0000001wxyzab 001wxyz * 000001wxyzabc 010wxyz * 00001wxyzabcd 011wxyz * 0001wxyzabcde 100wxyz * 001wxyzabcdef 101wxyz * 01wxyzabcdefg 110wxyz * 1wxyzabcdefgh 111wxyz * * Each biased linear code has a leading 1 which identifies the segment * number. The value of the segment number is equal to 7 minus the number * of leading 0's. The quantization interval is directly available as the * four bits wxyz. * The trailing bits (a - h) are ignored. * * Ordinarily the complement of the resulting code word is used for * transmission, and so the code word is complemented before it is returned. * * For further information see John C. Bellamy's Digital Telephony, 1982, * John Wiley & Sons, pps 98-111 and 472-476. */ static unsigned char st_14linear2ulaw(PyInt16 pcm_val) /* 2's complement (14-bit range) */ { PyInt16 mask; PyInt16 seg; unsigned char uval; /* The original sox code does this in the calling function, not here */ pcm_val = pcm_val >> 2; /* u-law inverts all bits */ /* Get the sign and the magnitude of the value. */ if (pcm_val < 0) { pcm_val = -pcm_val; mask = 0x7F; } else { mask = 0xFF; } if ( pcm_val > CLIP ) pcm_val = CLIP; /* clip the magnitude */ pcm_val += (BIAS >> 2); /* Convert the scaled magnitude to segment number. */ seg = search(pcm_val, seg_uend, 8); /* * Combine the sign, segment, quantization bits; * and complement the code word. */ if (seg >= 8) /* out of range, return maximum value. */ return (unsigned char) (0x7F ^ mask); else { uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF); return (uval ^ mask); } } static PyInt16 _st_alaw2linear16[256] = { -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736, -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944, -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136, -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472, -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568, -344, -328, -376, -360, -280, -264, -312, -296, -472, -456, -504, -488, -408, -392, -440, -424, -88, -72, -120, -104, -24, -8, -56, -40, -216, -200, -248, -232, -152, -136, -184, -168, -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, -688, -656, -752, -720, -560, -528, -624, -592, -944, -912, -1008, -976, -816, -784, -880, -848, 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736, 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784, 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368, 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392, 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944, 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136, 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472, 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568, 344, 328, 376, 360, 280, 264, 312, 296, 472, 456, 504, 488, 408, 392, 440, 424, 88, 72, 120, 104, 24, 8, 56, 40, 216, 200, 248, 232, 152, 136, 184, 168, 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184, 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696, 688, 656, 752, 720, 560, 528, 624, 592, 944, 912, 1008, 976, 816, 784, 880, 848 }; /* * linear2alaw() accepts an 13-bit signed integer and encodes it as A-law data * stored in a unsigned char. This function should only be called with * the data shifted such that it only contains information in the lower * 13-bits. * * Linear Input Code Compressed Code * ------------------------ --------------- * 0000000wxyza 000wxyz * 0000001wxyza 001wxyz * 000001wxyzab 010wxyz * 00001wxyzabc 011wxyz * 0001wxyzabcd 100wxyz * 001wxyzabcde 101wxyz * 01wxyzabcdef 110wxyz * 1wxyzabcdefg 111wxyz * * For further information see John C. Bellamy's Digital Telephony, 1982, * John Wiley & Sons, pps 98-111 and 472-476. */ static unsigned char st_linear2alaw(PyInt16 pcm_val) /* 2's complement (13-bit range) */ { PyInt16 mask; short seg; unsigned char aval; /* The original sox code does this in the calling function, not here */ pcm_val = pcm_val >> 3; /* A-law using even bit inversion */ if (pcm_val >= 0) { mask = 0xD5; /* sign (7th) bit = 1 */ } else { mask = 0x55; /* sign bit = 0 */ pcm_val = -pcm_val - 1; } /* Convert the scaled magnitude to segment number. */ seg = search(pcm_val, seg_aend, 8); /* Combine the sign, segment, and quantization bits. */ if (seg >= 8) /* out of range, return maximum value. */ return (unsigned char) (0x7F ^ mask); else { aval = (unsigned char) seg << SEG_SHIFT; if (seg < 2) aval |= (pcm_val >> 1) & QUANT_MASK; else aval |= (pcm_val >> seg) & QUANT_MASK; return (aval ^ mask); } } /* 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)) #if WORDS_BIGENDIAN #define GETINT24(cp, i) ( \ ((unsigned char *)(cp) + (i))[2] + \ (((unsigned char *)(cp) + (i))[1] << 8) + \ (((signed char *)(cp) + (i))[0] << 16) ) #else #define GETINT24(cp, i) ( \ ((unsigned char *)(cp) + (i))[0] + \ (((unsigned char *)(cp) + (i))[1] << 8) + \ (((signed char *)(cp) + (i))[2] << 16) ) #endif #if WORDS_BIGENDIAN #define SETINT24(cp, i, val) do { \ ((unsigned char *)(cp) + (i))[2] = (int)(val); \ ((unsigned char *)(cp) + (i))[1] = (int)(val) >> 8; \ ((signed char *)(cp) + (i))[0] = (int)(val) >> 16; \ } while (0) #else #define SETINT24(cp, i, val) do { \ ((unsigned char *)(cp) + (i))[0] = (int)(val); \ ((unsigned char *)(cp) + (i))[1] = (int)(val) >> 8; \ ((signed char *)(cp) + (i))[2] = (int)(val) >> 16; \ } while (0) #endif """ C_SOURCE = _AUDIOOP_C_MODULE + r""" #include static const int maxvals[] = {0, 0x7F, 0x7FFF, 0x7FFFFF, 0x7FFFFFFF}; /* -1 trick is needed on Windows to support -0x80000000 without a warning */ static const int minvals[] = {0, -0x80, -0x8000, -0x800000, -0x7FFFFFFF-1}; static int fbound(double val, double minval, double maxval) { if (val > maxval) val = maxval; else if (val < minval + 1) val = minval; return val; } static int gcd(int a, int b) { while (b > 0) { int tmp = a % b; a = b; b = tmp; } return a; } int ratecv(char* rv, char* cp, size_t len, int size, int nchannels, int inrate, int outrate, int* state_d, int* prev_i, int* cur_i, int weightA, int weightB) { char *ncp = rv; int d, chan; /* divide inrate and outrate by their greatest common divisor */ d = gcd(inrate, outrate); inrate /= d; outrate /= d; /* divide weightA and weightB by their greatest common divisor */ d = gcd(weightA, weightB); weightA /= d; weightA /= d; d = *state_d; for (;;) { while (d < 0) { if (len == 0) { *state_d = d; return ncp - rv; } for (chan = 0; chan < nchannels; chan++) { prev_i[chan] = cur_i[chan]; if (size == 1) cur_i[chan] = ((int)*CHARP(cp, 0)) << 24; else if (size == 2) cur_i[chan] = ((int)*SHORTP(cp, 0)) << 16; else if (size == 3) cur_i[chan] = ((int)GETINT24(cp, 0)) << 8; else if (size == 4) cur_i[chan] = (int)*LONGP(cp, 0); cp += size; /* implements a simple digital filter */ cur_i[chan] = (int)( ((double)weightA * (double)cur_i[chan] + (double)weightB * (double)prev_i[chan]) / ((double)weightA + (double)weightB)); } len--; d += outrate; } while (d >= 0) { for (chan = 0; chan < nchannels; chan++) { int cur_o; cur_o = (int)(((double)prev_i[chan] * (double)d + (double)cur_i[chan] * (double)(outrate - d)) / (double)outrate); if (size == 1) *CHARP(ncp, 0) = (signed char)(cur_o >> 24); else if (size == 2) *SHORTP(ncp, 0) = (short)(cur_o >> 16); else if (size == 3) SETINT24(ncp, 0, cur_o >> 8); else if (size == 4) *LONGP(ncp, 0) = (Py_Int32)(cur_o); ncp += size; } d -= inrate; } } } void tostereo(char* rv, char* cp, size_t len, int size, double fac1, double fac2) { int val1, val2, val = 0; double fval, maxval, minval; char *ncp = rv; int i; maxval = (double) maxvals[size]; minval = (double) minvals[size]; 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 == 3 ) val = (int)GETINT24(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); fval = (double)val*fac1; val1 = (int)floor(fbound(fval, minval, maxval)); fval = (double)val*fac2; val2 = (int)floor(fbound(fval, minval, maxval)); if ( size == 1 ) *CHARP(ncp, i*2) = (signed char)val1; else if ( size == 2 ) *SHORTP(ncp, i*2) = (short)val1; else if ( size == 3 ) SETINT24(ncp, i*2, 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 == 3 ) SETINT24(ncp, i*2+3, val2); else if ( size == 4 ) *LONGP(ncp, i*2+4) = (Py_Int32)val2; } } void add(char* rv, char* cp1, char* cp2, size_t len1, int size) { int i; int val1 = 0, val2 = 0, minval, maxval, newval; char* ncp = rv; maxval = maxvals[size]; minval = minvals[size]; 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 == 3 ) val1 = (int)GETINT24(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 == 3 ) val2 = (int)GETINT24(cp2, i); else if ( size == 4 ) val2 = (int)*LONGP(cp2, i); if (size < 4) { newval = val1 + val2; /* truncate in case of overflow */ if (newval > maxval) newval = maxval; else if (newval < minval) newval = minval; } else { double fval = (double)val1 + (double)val2; /* truncate in case of overflow */ newval = (int)floor(fbound(fval, minval, maxval)); } if ( size == 1 ) *CHARP(ncp, i) = (signed char)newval; else if ( size == 2 ) *SHORTP(ncp, i) = (short)newval; else if ( size == 3 ) SETINT24(ncp, i, newval); else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)newval; } } void lin2adcpm(unsigned char* ncp, unsigned char* cp, size_t len, size_t size, int* state) { int step, outputbuffer = 0, bufferstep; int val = 0; int diff, vpdiff, sign, delta; size_t i; int valpred = state[0]; int index = state[1]; 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 == 3 ) val = ((int)GETINT24(cp, i)) >> 8; 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; } state[0] = valpred; state[1] = index; } void adcpm2lin(unsigned char* ncp, unsigned char* cp, size_t len, size_t size, int* state) { int step, inputbuffer = 0, bufferstep; int val = 0; int diff, vpdiff, sign, delta; size_t i; int valpred = state[0]; int index = state[1]; 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 == 3 ) SETINT24(ncp, i, valpred << 8); else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(valpred<<16); } state[0] = valpred; state[1] = index; } """ ffi.set_source("_audioop_cffi", C_SOURCE) if __name__ == "__main__": import sys print('using python from', sys.executable) ffi.compile(verbose=2)