/* * 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_routines.h * * This file contains functions for arithmatically encoding and * decoding DFT coefficients. * */ #include "arith_routines.h" static const WebRtc_Word32 kHistEdgesQ15[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}; static const int kCdfSlopeQ0[51] = { /* Q0 */ 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}; static const int kCdfQ16[51] = { /* Q16 */ 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}; /* function to be converted to fixed point */ static __inline WebRtc_UWord32 piecewise(WebRtc_Word32 xinQ15) { WebRtc_Word32 ind, qtmp1, qtmp2, qtmp3; WebRtc_UWord32 tmpUW32; qtmp2 = xinQ15; if (qtmp2 < kHistEdgesQ15[0]) { qtmp2 = kHistEdgesQ15[0]; } if (qtmp2 > kHistEdgesQ15[50]) { qtmp2 = kHistEdgesQ15[50]; } qtmp1 = qtmp2 - kHistEdgesQ15[0]; /* Q15 - Q15 = Q15 */ ind = (qtmp1 * 5) >> 16; /* 2^16 / 5 = 0.4 in Q15 */ /* Q15 -> Q0 */ qtmp1 = qtmp2 - kHistEdgesQ15[ind]; /* Q15 - Q15 = Q15 */ qtmp2 = kCdfSlopeQ0[ind] * qtmp1; /* Q0 * Q15 = Q15 */ qtmp3 = qtmp2>>15; /* Q15 -> Q0 */ tmpUW32 = kCdfQ16[ind] + qtmp3; /* Q0 + Q0 = Q0 */ return tmpUW32; } int WebRtcIsac_EncLogisticMulti2( Bitstr *streamdata, /* in-/output struct containing bitstream */ WebRtc_Word16 *dataQ7, /* input: data vector */ const WebRtc_UWord16 *envQ8, /* input: side info vector defining the width of the pdf */ const int N, /* input: data vector length / 2 */ const WebRtc_Word16 isSWB12kHz) { WebRtc_UWord32 W_lower, W_upper; WebRtc_UWord32 W_upper_LSB, W_upper_MSB; WebRtc_UWord8 *stream_ptr; WebRtc_UWord8 *maxStreamPtr; WebRtc_UWord8 *stream_ptr_carry; WebRtc_UWord32 cdf_lo, cdf_hi; int k; /* point to beginning of stream buffer */ stream_ptr = streamdata->stream + streamdata->stream_index; W_upper = streamdata->W_upper; maxStreamPtr = streamdata->stream + STREAM_SIZE_MAX_60 - 1; for (k = 0; k < N; k++) { /* compute cdf_lower and cdf_upper by evaluating the piecewise linear cdf */ cdf_lo = piecewise((*dataQ7 - 64) * *envQ8); cdf_hi = piecewise((*dataQ7 + 64) * *envQ8); /* test and clip if probability gets too small */ while (cdf_lo+1 >= cdf_hi) { /* clip */ if (*dataQ7 > 0) { *dataQ7 -= 128; cdf_hi = cdf_lo; cdf_lo = piecewise((*dataQ7 - 64) * *envQ8); } else { *dataQ7 += 128; cdf_lo = cdf_hi; cdf_hi = piecewise((*dataQ7 + 64) * *envQ8); } } dataQ7++; // increment only once per 4 iterations for SWB-16kHz or WB // increment only once per 2 iterations for SWB-12kHz envQ8 += (isSWB12kHz)? (k & 1):((k & 1) & (k >> 1)); /* update interval */ W_upper_LSB = W_upper & 0x0000FFFF; W_upper_MSB = W_upper >> 16; W_lower = W_upper_MSB * cdf_lo; W_lower += (W_upper_LSB * cdf_lo) >> 16; W_upper = W_upper_MSB * cdf_hi; W_upper += (W_upper_LSB * cdf_hi) >> 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 */ stream_ptr_carry = stream_ptr; while (!(++(*--stream_ptr_carry))); } /* renormalize interval, store most significant byte of streamval and update streamval */ while ( !(W_upper & 0xFF000000) ) /* W_upper < 2^24 */ { W_upper <<= 8; *stream_ptr++ = (WebRtc_UWord8) (streamdata->streamval >> 24); if(stream_ptr > maxStreamPtr) { return -ISAC_DISALLOWED_BITSTREAM_LENGTH; } streamdata->streamval <<= 8; } } /* calculate new stream_index */ streamdata->stream_index = (int)(stream_ptr - streamdata->stream); streamdata->W_upper = W_upper; return 0; } int WebRtcIsac_DecLogisticMulti2( WebRtc_Word16 *dataQ7, /* output: data vector */ Bitstr *streamdata, /* in-/output struct containing bitstream */ const WebRtc_UWord16 *envQ8, /* input: side info vector defining the width of the pdf */ const WebRtc_Word16 *ditherQ7,/* input: dither vector */ const int N, /* input: data vector length */ const WebRtc_Word16 isSWB12kHz) { WebRtc_UWord32 W_lower, W_upper; WebRtc_UWord32 W_tmp; WebRtc_UWord32 W_upper_LSB, W_upper_MSB; WebRtc_UWord32 streamval; const WebRtc_UWord8 *stream_ptr; WebRtc_UWord32 cdf_tmp; WebRtc_Word16 candQ7; int k; stream_ptr = streamdata->stream + streamdata->stream_index; W_upper = streamdata->W_upper; if (streamdata->stream_index == 0) /* first time decoder is called for this stream */ { /* read first word from bytestream */ streamval = *stream_ptr << 24; streamval |= *++stream_ptr << 16; streamval |= *++stream_ptr << 8; streamval |= *++stream_ptr; } else { streamval = streamdata->streamval; } for (k = 0; k < N; k++) { /* find the integer *data for which streamval lies in [W_lower+1, W_upper] */ W_upper_LSB = W_upper & 0x0000FFFF; W_upper_MSB = W_upper >> 16; /* find first candidate by inverting the logistic cdf */ candQ7 = - *ditherQ7 + 64; cdf_tmp = piecewise(candQ7 * *envQ8); W_tmp = W_upper_MSB * cdf_tmp; W_tmp += (W_upper_LSB * cdf_tmp) >> 16; if (streamval > W_tmp) { W_lower = W_tmp; candQ7 += 128; cdf_tmp = piecewise(candQ7 * *envQ8); W_tmp = W_upper_MSB * cdf_tmp; W_tmp += (W_upper_LSB * cdf_tmp) >> 16; while (streamval > W_tmp) { W_lower = W_tmp; candQ7 += 128; cdf_tmp = piecewise(candQ7 * *envQ8); W_tmp = W_upper_MSB * cdf_tmp; W_tmp += (W_upper_LSB * cdf_tmp) >> 16; /* error check */ if (W_lower == W_tmp) return -1; } W_upper = W_tmp; /* another sample decoded */ *dataQ7 = candQ7 - 64; } else { W_upper = W_tmp; candQ7 -= 128; cdf_tmp = piecewise(candQ7 * *envQ8); W_tmp = W_upper_MSB * cdf_tmp; W_tmp += (W_upper_LSB * cdf_tmp) >> 16; while ( !(streamval > W_tmp) ) { W_upper = W_tmp; candQ7 -= 128; cdf_tmp = piecewise(candQ7 * *envQ8); W_tmp = W_upper_MSB * cdf_tmp; W_tmp += (W_upper_LSB * cdf_tmp) >> 16; /* error check */ if (W_upper == W_tmp) return -1; } W_lower = W_tmp; /* another sample decoded */ *dataQ7 = candQ7 + 64; } ditherQ7++; dataQ7++; // increment only once per 4 iterations for SWB-16kHz or WB // increment only once per 2 iterations for SWB-12kHz envQ8 += (isSWB12kHz)? (k & 1):((k & 1) & (k >> 1)); /* shift interval to start at zero */ W_upper -= ++W_lower; /* add integer to bitstream */ streamval -= W_lower; /* renormalize interval and update streamval */ while ( !(W_upper & 0xFF000000) ) /* W_upper < 2^24 */ { /* read next byte from stream */ streamval = (streamval << 8) | *++stream_ptr; W_upper <<= 8; } } streamdata->stream_index = (int)(stream_ptr - 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; else return streamdata->stream_index - 1; }