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freeswitch/src/mod/codecs/mod_isac/arith_routines_logist.c
Anthony Minessale 224943f0b6 remove case from mod_iSAC sheesh....
2012-01-24 16:58:28 -06:00

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/*
* 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;
}
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