blob: 808aeb7fd9ddb4c554331bd595238a23f07b8f21 [file] [log] [blame]
 /* * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ /* * arith_routinslogist.c * * This C file contains arithmetic encode and decode logistic * */ #include "arith_routins.h" /* Tables for piecewise linear cdf functions: y = k*x */ /* x Points for function piecewise() in Q15 */ static const int32_t kHistEdges[51] = { -327680, -314573, -301466, -288359, -275252, -262144, -249037, -235930, -222823, -209716, -196608, -183501, -170394, -157287, -144180, -131072, -117965, -104858, -91751, -78644, -65536, -52429, -39322, -26215, -13108, 0, 13107, 26214, 39321, 52428, 65536, 78643, 91750, 104857, 117964, 131072, 144179, 157286, 170393, 183500, 196608, 209715, 222822, 235929, 249036, 262144, 275251, 288358, 301465, 314572, 327680 }; /* k Points for function piecewise() in Q0 */ static const uint16_t kCdfSlope[51] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 13, 23, 47, 87, 154, 315, 700, 1088, 2471, 6064, 14221, 21463, 36634, 36924, 19750, 13270, 5806, 2312, 1095, 660, 316, 145, 86, 41, 32, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 2, 0 }; /* y Points for function piecewise() in Q0 */ static const uint16_t kCdfLogistic[51] = { 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 29, 38, 57, 92, 153, 279, 559, 994, 1983, 4408, 10097, 18682, 33336, 48105, 56005, 61313, 63636, 64560, 64998, 65262, 65389, 65447, 65481, 65497, 65510, 65512, 65514, 65516, 65518, 65520, 65522, 65524, 65526, 65528, 65530, 65532, 65534, 65535 }; /**************************************************************************** * WebRtcIsacfix_Piecewise(...) * * Piecewise linear function * * Input: * - xinQ15 : input value x in Q15 * * Return value : korresponding y-value in Q0 */ static __inline uint16_t WebRtcIsacfix_Piecewise(int32_t xinQ15) { int32_t ind; int32_t qtmp1; uint16_t qtmp2; /* Find index for x-value */ qtmp1 = WEBRTC_SPL_SAT(kHistEdges[50],xinQ15,kHistEdges[0]); ind = WEBRTC_SPL_MUL(5, qtmp1 - kHistEdges[0]); ind >>= 16; /* Calculate corresponding y-value ans return*/ qtmp1 = qtmp1 - kHistEdges[ind]; qtmp2 = (uint16_t)WEBRTC_SPL_RSHIFT_U32( WEBRTC_SPL_UMUL_32_16(qtmp1,kCdfSlope[ind]), 15); return (kCdfLogistic[ind] + qtmp2); } /**************************************************************************** * WebRtcIsacfix_EncLogisticMulti2(...) * * Arithmetic coding of spectrum. * * Input: * - streamData : in-/output struct containing bitstream * - dataQ7 : data vector in Q7 * - envQ8 : side info vector defining the width of the pdf * in Q8 * - lenData : data vector length * * Return value : 0 if ok, * <0 otherwise. */ int WebRtcIsacfix_EncLogisticMulti2(Bitstr_enc *streamData, int16_t *dataQ7, const uint16_t *envQ8, const int16_t lenData) { uint32_t W_lower; uint32_t W_upper; uint16_t W_upper_LSB; uint16_t W_upper_MSB; uint16_t *streamPtr; uint16_t *maxStreamPtr; uint16_t *streamPtrCarry; uint16_t negcarry; uint32_t cdfLo; uint32_t cdfHi; int k; /* point to beginning of stream buffer * and set maximum streamPtr value */ streamPtr = streamData->stream + streamData->stream_index; maxStreamPtr = streamData->stream + STREAM_MAXW16_60MS - 1; W_upper = streamData->W_upper; for (k = 0; k < lenData; k++) { /* compute cdf_lower and cdf_upper by evaluating the * WebRtcIsacfix_Piecewise linear cdf */ cdfLo = WebRtcIsacfix_Piecewise(WEBRTC_SPL_MUL_16_U16(*dataQ7 - 64, *envQ8)); cdfHi = WebRtcIsacfix_Piecewise(WEBRTC_SPL_MUL_16_U16(*dataQ7 + 64, *envQ8)); /* test and clip if probability gets too small */ while ((cdfLo + 1) >= cdfHi) { /* clip */ if (*dataQ7 > 0) { *dataQ7 -= 128; cdfHi = cdfLo; cdfLo = WebRtcIsacfix_Piecewise( WEBRTC_SPL_MUL_16_U16(*dataQ7 - 64, *envQ8)); } else { *dataQ7 += 128; cdfLo = cdfHi; cdfHi = WebRtcIsacfix_Piecewise( WEBRTC_SPL_MUL_16_U16(*dataQ7 + 64, *envQ8)); } } dataQ7++; /* increment only once per 4 iterations */ envQ8 += (k & 1) & (k >> 1); /* update interval */ W_upper_LSB = (uint16_t)W_upper; W_upper_MSB = (uint16_t)WEBRTC_SPL_RSHIFT_U32(W_upper, 16); W_lower = WEBRTC_SPL_UMUL_32_16(cdfLo, W_upper_MSB); W_lower += (cdfLo * W_upper_LSB) >> 16; W_upper = WEBRTC_SPL_UMUL_32_16(cdfHi, W_upper_MSB); W_upper += (cdfHi * W_upper_LSB) >> 16; /* shift interval such that it begins at zero */ W_upper -= ++W_lower; /* add integer to bitstream */ streamData->streamval += W_lower; /* handle carry */ if (streamData->streamval < W_lower) { /* propagate carry */ streamPtrCarry = streamPtr; if (streamData->full == 0) { negcarry = *streamPtrCarry; negcarry += 0x0100; *streamPtrCarry = negcarry; while (!(negcarry)) { negcarry = *--streamPtrCarry; negcarry++; *streamPtrCarry = negcarry; } } else { while (!(++(*--streamPtrCarry))); } } /* renormalize interval, store most significant byte of streamval and update streamval * W_upper < 2^24 */ while ( !(W_upper & 0xFF000000) ) { W_upper <<= 8; if (streamData->full == 0) { *streamPtr++ += (uint16_t) WEBRTC_SPL_RSHIFT_U32( streamData->streamval, 24); streamData->full = 1; } else { *streamPtr = (uint16_t)((streamData->streamval >> 24) << 8); streamData->full = 0; } if( streamPtr > maxStreamPtr ) return -ISAC_DISALLOWED_BITSTREAM_LENGTH; streamData->streamval <<= 8; } } /* calculate new stream_index */ streamData->stream_index = streamPtr - streamData->stream; streamData->W_upper = W_upper; return 0; } /**************************************************************************** * WebRtcIsacfix_DecLogisticMulti2(...) * * Arithmetic decoding of spectrum. * * Input: * - streamData : in-/output struct containing bitstream * - envQ8 : side info vector defining the width of the pdf * in Q8 * - lenData : data vector length * * Input/Output: * - dataQ7 : input: dither vector, output: data vector * * Return value : number of bytes in the stream so far * -1 if error detected */ int WebRtcIsacfix_DecLogisticMulti2(int16_t *dataQ7, Bitstr_dec *streamData, const int32_t *envQ8, const int16_t lenData) { uint32_t W_lower; uint32_t W_upper; uint32_t W_tmp; uint16_t W_upper_LSB; uint16_t W_upper_MSB; uint32_t streamVal; uint16_t cdfTmp; int32_t res; int32_t inSqrt; int32_t newRes; const uint16_t *streamPtr; int16_t candQ7; int16_t envCount; uint16_t tmpARSpecQ8 = 0; int k, i; int offset = 0; /* point to beginning of stream buffer */ streamPtr = streamData->stream + streamData->stream_index; W_upper = streamData->W_upper; /* Check if it is first time decoder is called for this stream */ if (streamData->stream_index == 0) { /* read first word from bytestream */ streamVal = (uint32_t)(*streamPtr++) << 16; streamVal |= *streamPtr++; } else { streamVal = streamData->streamval; } res = 1 << (WebRtcSpl_GetSizeInBits(envQ8[0]) >> 1); envCount = 0; /* code assumes lenData%4 == 0 */ for (k = 0; k < lenData; k += 4) { int k4; /* convert to magnitude spectrum, by doing square-roots (modified from SPLIB) */ inSqrt = envQ8[envCount]; i = 10; /* For safty reasons */ if (inSqrt < 0) inSqrt=-inSqrt; newRes = (inSqrt / res + res) >> 1; do { res = newRes; newRes = (inSqrt / res + res) >> 1; } while (newRes != res && i-- > 0); tmpARSpecQ8 = (uint16_t)newRes; for(k4 = 0; k4 < 4; k4++) { /* find the integer *data for which streamVal lies in [W_lower+1, W_upper] */ W_upper_LSB = (uint16_t) (W_upper & 0x0000FFFF); W_upper_MSB = (uint16_t) WEBRTC_SPL_RSHIFT_U32(W_upper, 16); /* find first candidate by inverting the logistic cdf * Input dither value collected from io-stream */ candQ7 = - *dataQ7 + 64; cdfTmp = WebRtcIsacfix_Piecewise(WEBRTC_SPL_MUL_16_U16(candQ7, tmpARSpecQ8)); W_tmp = (uint32_t)cdfTmp * W_upper_MSB; W_tmp += ((uint32_t)cdfTmp * (uint32_t)W_upper_LSB) >> 16; if (streamVal > W_tmp) { W_lower = W_tmp; candQ7 += 128; cdfTmp = WebRtcIsacfix_Piecewise(WEBRTC_SPL_MUL_16_U16(candQ7, tmpARSpecQ8)); W_tmp = (uint32_t)cdfTmp * W_upper_MSB; W_tmp += ((uint32_t)cdfTmp * (uint32_t)W_upper_LSB) >> 16; while (streamVal > W_tmp) { W_lower = W_tmp; candQ7 += 128; cdfTmp = WebRtcIsacfix_Piecewise( WEBRTC_SPL_MUL_16_U16(candQ7, tmpARSpecQ8)); W_tmp = (uint32_t)cdfTmp * W_upper_MSB; W_tmp += ((uint32_t)cdfTmp * (uint32_t)W_upper_LSB) >> 16; /* error check */ if (W_lower == W_tmp) { return -1; } } W_upper = W_tmp; /* Output value put in dataQ7: another sample decoded */ *dataQ7 = candQ7 - 64; } else { W_upper = W_tmp; candQ7 -= 128; cdfTmp = WebRtcIsacfix_Piecewise(WEBRTC_SPL_MUL_16_U16(candQ7, tmpARSpecQ8)); W_tmp = (uint32_t)cdfTmp * W_upper_MSB; W_tmp += ((uint32_t)cdfTmp * (uint32_t)W_upper_LSB) >> 16; while ( !(streamVal > W_tmp) ) { W_upper = W_tmp; candQ7 -= 128; cdfTmp = WebRtcIsacfix_Piecewise( WEBRTC_SPL_MUL_16_U16(candQ7, tmpARSpecQ8)); W_tmp = (uint32_t)cdfTmp * W_upper_MSB; W_tmp += ((uint32_t)cdfTmp * (uint32_t)W_upper_LSB) >> 16; /* error check */ if (W_upper == W_tmp){ return -1; } } W_lower = W_tmp; /* Output value put in dataQ7: another sample decoded */ *dataQ7 = candQ7 + 64; } dataQ7++; /* shift interval to start at zero */ W_upper -= ++W_lower; /* add integer to bitstream */ streamVal -= W_lower; /* renormalize interval and update streamVal * W_upper < 2^24 */ while ( !(W_upper & 0xFF000000) ) { if (streamPtr < streamData->stream + streamData->stream_size) { /* read next byte from stream */ if (streamData->full == 0) { streamVal = (streamVal << 8) | (*streamPtr++ & 0x00FF); streamData->full = 1; } else { streamVal = (streamVal << 8) | (*streamPtr >> 8); streamData->full = 0; } } else { /* Intending to read outside the stream. This can happen for the last * two or three bytes. It is how the algorithm is implemented. Do * not read from the bit stream and insert zeros instead. */ streamVal <<= 8; if (streamData->full == 0) { offset++; // We would have incremented the pointer in this case. streamData->full = 1; } else { streamData->full = 0; } } W_upper <<= 8; } } envCount++; } streamData->stream_index = streamPtr + offset - streamData->stream; streamData->W_upper = W_upper; streamData->streamval = streamVal; /* find number of bytes in original stream (determined by current interval width) */ if ( W_upper > 0x01FFFFFF ) return (streamData->stream_index*2 - 3 + !streamData->full); else return (streamData->stream_index*2 - 2 + !streamData->full); }