ffmpeg/libavcodec/ra288.c

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/*
* RealAudio 2.0 (28.8K)
* Copyright (c) 2003 the ffmpeg project
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#define ALT_BITSTREAM_READER_LE
#include "bitstream.h"
#include "ra288.h"
typedef struct {
float history[8];
float output[40];
float pr1[36];
float pr2[10];
int phase;
float st1a[111], st1b[37], st1[37];
float st2a[38], st2b[11], st2[11];
float sb[41];
float lhist[10];
} Real288_internal;
static inline float scalar_product_float(const float * v1, const float * v2,
int size)
{
float res = 0.;
while (size--)
res += *v1++ * *v2++;
return res;
}
/* Decode and produce output */
static void decode(Real288_internal *glob, float gain, int cb_coef)
{
int x, y;
double sumsum;
float sum, buffer[5];
memmove(glob->sb + 5, glob->sb, 36 * sizeof(*glob->sb));
for (x=4; x >= 0; x--)
glob->sb[x] = -scalar_product_float(glob->sb + x + 1, glob->pr1, 36);
/* convert log and do rms */
sum = 32. - scalar_product_float(glob->pr2, glob->lhist, 10);
sum = av_clipf(sum, 0, 60);
sumsum = exp(sum * 0.1151292546497) * gain; /* pow(10.0,sum/20)*f */
for (x=0; x < 5; x++)
buffer[x] = codetable[cb_coef][x] * sumsum;
sum = scalar_product_float(buffer, buffer, 5) / 5;
sum = FFMAX(sum, 1);
/* shift and store */
memmove(glob->lhist, glob->lhist - 1, 10 * sizeof(*glob->lhist));
*glob->lhist = glob->history[glob->phase] = 10 * log10(sum) - 32;
for (x=1; x < 5; x++)
for (y=x-1; y >= 0; y--)
buffer[x] -= glob->pr1[x-y-1] * buffer[y];
/* output */
for (x=0; x < 5; x++) {
glob->output[glob->phase*5+x] = glob->sb[4-x] =
av_clipf(glob->sb[4-x] + buffer[x], -4095, 4095);
}
}
/* column multiply */
static void colmult(float *tgt, const float *m1, const float *m2, int n)
{
while (n--)
*(tgt++) = (*(m1++)) * (*(m2++));
}
static int pred(const float *in, float *tgt, int n)
{
int x, y;
double f0, f1, f2;
if (in[n] == 0)
return 0;
if ((f0 = *in) <= 0)
return 0;
in--; // To avoid a -1 subtraction in the inner loop
for (x=1; x <= n; x++) {
float *p1 = tgt + x - 1;
float *p2 = tgt;
f1 = in[x+1];
for (y=0; y < x - 1; y++)
f1 += in[x-y]*tgt[y];
*(p1--) = f2 = -f1/f0;
for (y=x >> 1; y--;) {
float temp = *p2 + *p1 * f2;
*(p1--) += *p2 * f2;
*(p2++) = temp;
}
if ((f0 += f1*f2) < 0)
return 0;
}
return 1;
}
/* product sum (lsf) */
static void prodsum(float *tgt, const float *src, int len, int n)
{
for (; n >= 0; n--)
tgt[n] = scalar_product_float(src, src - n, len);
}
static void co(int n, int i, int j, const float *in, float *out, float *st1,
float *st2, const float *table)
{
int a, b, c;
unsigned int x;
const float *fp;
float buffer1[37];
float buffer2[37];
float work[111];
/* rotate and multiply */
c = (b = (a = n + i) + j) - i;
fp = st1 + i;
for (x=0; x < b; x++) {
if (x == c)
fp=in;
work[x] = *(table++) * (*(st1++) = *(fp++));
}
prodsum(buffer1, work + n, i, n);
prodsum(buffer2, work + a, j, n);
for (x=0;x<=n;x++) {
*st2 = *st2 * (0.5625) + buffer1[x];
out[x] = *(st2++) + buffer2[x];
}
*out *= 1.00390625; /* to prevent clipping */
}
static void update(Real288_internal *glob)
{
float buffer1[40], temp1[37];
float buffer2[8], temp2[11];
memcpy(buffer1 , glob->output + 20, 20*sizeof(*buffer1));
memcpy(buffer1 + 20, glob->output , 20*sizeof(*buffer1));
co(36, 40, 35, buffer1, temp1, glob->st1a, glob->st1b, table1);
if (pred(temp1, glob->st1, 36))
colmult(glob->pr1, glob->st1, table1a, 36);
memcpy(buffer2 , glob->history + 4, 4*sizeof(*buffer2));
memcpy(buffer2 + 4, glob->history , 4*sizeof(*buffer2));
co(10, 8, 20, buffer2, temp2, glob->st2a, glob->st2b, table2);
if (pred(temp2, glob->st2, 10))
colmult(glob->pr2, glob->st2, table2a, 10);
}
/* Decode a block (celp) */
static int ra288_decode_frame(AVCodecContext * avctx, void *data,
int *data_size, const uint8_t * buf,
int buf_size)
{
int16_t *out = data;
int x, y;
Real288_internal *glob = avctx->priv_data;
GetBitContext gb;
if (buf_size < avctx->block_align) {
av_log(avctx, AV_LOG_ERROR,
"Error! Input buffer is too small [%d<%d]\n",
buf_size, avctx->block_align);
return 0;
}
init_get_bits(&gb, buf, avctx->block_align * 8);
for (x=0; x < 32; x++) {
float gain = amptable[get_bits(&gb, 3)];
int cb_coef = get_bits(&gb, 6 + (x&1));
glob->phase = x & 7;
decode(glob, gain, cb_coef);
for (y=0; y < 5; y++)
*(out++) = 8 * glob->output[glob->phase*5 + y];
if (glob->phase == 3)
update(glob);
}
*data_size = (char *)out - (char *)data;
return avctx->block_align;
}
AVCodec ra_288_decoder =
{
"real_288",
CODEC_TYPE_AUDIO,
CODEC_ID_RA_288,
sizeof(Real288_internal),
NULL,
NULL,
NULL,
ra288_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("RealAudio 2.0 (28.8K)"),
};