mirror of https://git.ffmpeg.org/ffmpeg.git
353 lines
9.6 KiB
C
353 lines
9.6 KiB
C
/*
|
|
* Real Audio 1.0 (14.4K)
|
|
*
|
|
* Copyright (c) 2008 Vitor Sessak
|
|
* Copyright (c) 2003 Nick Kurshev
|
|
* Based on public domain decoder at http://www.honeypot.net/audio
|
|
*
|
|
* 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"
|
|
#include "bitstream.h"
|
|
#include "ra144.h"
|
|
#include "acelp_filters.h"
|
|
|
|
#define NBLOCKS 4 ///< number of subblocks within a block
|
|
#define BLOCKSIZE 40 ///< subblock size in 16-bit words
|
|
#define BUFFERSIZE 146 ///< the size of the adaptive codebook
|
|
|
|
|
|
typedef struct {
|
|
unsigned int old_energy; ///< previous frame energy
|
|
|
|
unsigned int lpc_tables[2][10];
|
|
|
|
/** LPC coefficients: lpc_coef[0] is the coefficients of the current frame
|
|
* and lpc_coef[1] of the previous one */
|
|
unsigned int *lpc_coef[2];
|
|
|
|
unsigned int lpc_refl_rms[2];
|
|
|
|
/** the current subblock padded by the last 10 values of the previous one*/
|
|
int16_t curr_sblock[50];
|
|
|
|
/** adaptive codebook. Its size is two units bigger to avoid a
|
|
* buffer overflow */
|
|
uint16_t adapt_cb[146+2];
|
|
} RA144Context;
|
|
|
|
static av_cold int ra144_decode_init(AVCodecContext * avctx)
|
|
{
|
|
RA144Context *ractx = avctx->priv_data;
|
|
|
|
ractx->lpc_coef[0] = ractx->lpc_tables[0];
|
|
ractx->lpc_coef[1] = ractx->lpc_tables[1];
|
|
|
|
avctx->sample_fmt = SAMPLE_FMT_S16;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Evaluate sqrt(x << 24). x must fit in 20 bits. This value is evaluated in an
|
|
* odd way to make the output identical to the binary decoder.
|
|
*/
|
|
static int t_sqrt(unsigned int x)
|
|
{
|
|
int s = 2;
|
|
while (x > 0xfff) {
|
|
s++;
|
|
x >>= 2;
|
|
}
|
|
|
|
return ff_sqrt(x << 20) << s;
|
|
}
|
|
|
|
/**
|
|
* Evaluate the LPC filter coefficients from the reflection coefficients.
|
|
* Does the inverse of the eval_refl() function.
|
|
*/
|
|
static void eval_coefs(int *coefs, const int *refl)
|
|
{
|
|
int buffer[10];
|
|
int *b1 = buffer;
|
|
int *b2 = coefs;
|
|
int i, j;
|
|
|
|
for (i=0; i < 10; i++) {
|
|
b1[i] = refl[i] << 4;
|
|
|
|
for (j=0; j < i; j++)
|
|
b1[j] = ((refl[i] * b2[i-j-1]) >> 12) + b2[j];
|
|
|
|
FFSWAP(int *, b1, b2);
|
|
}
|
|
|
|
for (i=0; i < 10; i++)
|
|
coefs[i] >>= 4;
|
|
}
|
|
|
|
/**
|
|
* Copy the last offset values of *source to *target. If those values are not
|
|
* enough to fill the target buffer, fill it with another copy of those values.
|
|
*/
|
|
static void copy_and_dup(int16_t *target, const int16_t *source, int offset)
|
|
{
|
|
source += BUFFERSIZE - offset;
|
|
|
|
memcpy(target, source, FFMIN(BLOCKSIZE, offset)*sizeof(*target));
|
|
if (offset < BLOCKSIZE)
|
|
memcpy(target + offset, source, (BLOCKSIZE - offset)*sizeof(*target));
|
|
}
|
|
|
|
/** inverse root mean square */
|
|
static int irms(const int16_t *data)
|
|
{
|
|
unsigned int i, sum = 0;
|
|
|
|
for (i=0; i < BLOCKSIZE; i++)
|
|
sum += data[i] * data[i];
|
|
|
|
if (sum == 0)
|
|
return 0; /* OOPS - division by zero */
|
|
|
|
return 0x20000000 / (t_sqrt(sum) >> 8);
|
|
}
|
|
|
|
static void add_wav(int16_t *dest, int n, int skip_first, int *m,
|
|
const int16_t *s1, const int8_t *s2, const int8_t *s3)
|
|
{
|
|
int i;
|
|
int v[3];
|
|
|
|
v[0] = 0;
|
|
for (i=!skip_first; i<3; i++)
|
|
v[i] = (gain_val_tab[n][i] * m[i]) >> gain_exp_tab[n];
|
|
|
|
for (i=0; i < BLOCKSIZE; i++)
|
|
dest[i] = (s1[i]*v[0] + s2[i]*v[1] + s3[i]*v[2]) >> 12;
|
|
}
|
|
|
|
static unsigned int rescale_rms(unsigned int rms, unsigned int energy)
|
|
{
|
|
return (rms * energy) >> 10;
|
|
}
|
|
|
|
static unsigned int rms(const int *data)
|
|
{
|
|
int i;
|
|
unsigned int res = 0x10000;
|
|
int b = 10;
|
|
|
|
for (i=0; i < 10; i++) {
|
|
res = (((0x1000000 - data[i]*data[i]) >> 12) * res) >> 12;
|
|
|
|
if (res == 0)
|
|
return 0;
|
|
|
|
while (res <= 0x3fff) {
|
|
b++;
|
|
res <<= 2;
|
|
}
|
|
}
|
|
|
|
return t_sqrt(res) >> b;
|
|
}
|
|
|
|
static void do_output_subblock(RA144Context *ractx, const uint16_t *lpc_coefs,
|
|
int gval, GetBitContext *gb)
|
|
{
|
|
uint16_t buffer_a[40];
|
|
uint16_t *block;
|
|
int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
|
|
int gain = get_bits(gb, 8);
|
|
int cb1_idx = get_bits(gb, 7);
|
|
int cb2_idx = get_bits(gb, 7);
|
|
int m[3];
|
|
|
|
if (cba_idx) {
|
|
cba_idx += BLOCKSIZE/2 - 1;
|
|
copy_and_dup(buffer_a, ractx->adapt_cb, cba_idx);
|
|
m[0] = (irms(buffer_a) * gval) >> 12;
|
|
} else {
|
|
m[0] = 0;
|
|
}
|
|
|
|
m[1] = (cb1_base[cb1_idx] * gval) >> 8;
|
|
m[2] = (cb2_base[cb2_idx] * gval) >> 8;
|
|
|
|
memmove(ractx->adapt_cb, ractx->adapt_cb + BLOCKSIZE,
|
|
(BUFFERSIZE - BLOCKSIZE) * sizeof(*ractx->adapt_cb));
|
|
|
|
block = ractx->adapt_cb + BUFFERSIZE - BLOCKSIZE;
|
|
|
|
add_wav(block, gain, cba_idx, m, buffer_a,
|
|
cb1_vects[cb1_idx], cb2_vects[cb2_idx]);
|
|
|
|
memcpy(ractx->curr_sblock, ractx->curr_sblock + 40,
|
|
10*sizeof(*ractx->curr_sblock));
|
|
|
|
if (ff_acelp_lp_synthesis_filter(ractx->curr_sblock + 10, lpc_coefs,
|
|
block, BLOCKSIZE, 10, 1, 0xfff))
|
|
memset(ractx->curr_sblock, 0, 50*sizeof(*ractx->curr_sblock));
|
|
}
|
|
|
|
static void int_to_int16(int16_t *out, const int *inp)
|
|
{
|
|
int i;
|
|
|
|
for (i=0; i < 30; i++)
|
|
*out++ = *inp++;
|
|
}
|
|
|
|
/**
|
|
* Evaluate the reflection coefficients from the filter coefficients.
|
|
* Does the inverse of the eval_coefs() function.
|
|
*
|
|
* @return 1 if one of the reflection coefficients is of magnitude greater than
|
|
* 4095, 0 if not.
|
|
*/
|
|
static int eval_refl(int *refl, const int16_t *coefs, RA144Context *ractx)
|
|
{
|
|
int b, i, j;
|
|
int buffer1[10];
|
|
int buffer2[10];
|
|
int *bp1 = buffer1;
|
|
int *bp2 = buffer2;
|
|
|
|
for (i=0; i < 10; i++)
|
|
buffer2[i] = coefs[i];
|
|
|
|
refl[9] = bp2[9];
|
|
|
|
if ((unsigned) bp2[9] + 0x1000 > 0x1fff) {
|
|
av_log(ractx, AV_LOG_ERROR, "Overflow. Broken sample?\n");
|
|
return 1;
|
|
}
|
|
|
|
for (i=8; i >= 0; i--) {
|
|
b = 0x1000-((bp2[i+1] * bp2[i+1]) >> 12);
|
|
|
|
if (!b)
|
|
b = -2;
|
|
|
|
for (j=0; j <= i; j++)
|
|
bp1[j] = ((bp2[j] - ((refl[i+1] * bp2[i-j]) >> 12)) * (0x1000000 / b)) >> 12;
|
|
|
|
if ((unsigned) bp1[i] + 0x1000 > 0x1fff)
|
|
return 1;
|
|
|
|
refl[i] = bp1[i];
|
|
|
|
FFSWAP(int *, bp1, bp2);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int interp(RA144Context *ractx, int16_t *out, int a,
|
|
int copyold, int energy)
|
|
{
|
|
int work[10];
|
|
int b = NBLOCKS - a;
|
|
int i;
|
|
|
|
// Interpolate block coefficients from the this frame forth block and
|
|
// last frame forth block
|
|
for (i=0; i<30; i++)
|
|
out[i] = (a * ractx->lpc_coef[0][i] + b * ractx->lpc_coef[1][i])>> 2;
|
|
|
|
if (eval_refl(work, out, ractx)) {
|
|
// The interpolated coefficients are unstable, copy either new or old
|
|
// coefficients
|
|
int_to_int16(out, ractx->lpc_coef[copyold]);
|
|
return rescale_rms(ractx->lpc_refl_rms[copyold], energy);
|
|
} else {
|
|
return rescale_rms(rms(work), energy);
|
|
}
|
|
}
|
|
|
|
/** Uncompress one block (20 bytes -> 160*2 bytes) */
|
|
static int ra144_decode_frame(AVCodecContext * avctx, void *vdata,
|
|
int *data_size, const uint8_t *buf, int buf_size)
|
|
{
|
|
static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
|
|
unsigned int refl_rms[4]; // RMS of the reflection coefficients
|
|
uint16_t block_coefs[4][30]; // LPC coefficients of each sub-block
|
|
unsigned int lpc_refl[10]; // LPC reflection coefficients of the frame
|
|
int i, j;
|
|
int16_t *data = vdata;
|
|
unsigned int energy;
|
|
|
|
RA144Context *ractx = avctx->priv_data;
|
|
GetBitContext gb;
|
|
|
|
if (*data_size < 2*160)
|
|
return -1;
|
|
|
|
if(buf_size < 20) {
|
|
av_log(avctx, AV_LOG_ERROR,
|
|
"Frame too small (%d bytes). Truncated file?\n", buf_size);
|
|
*data_size = 0;
|
|
return buf_size;
|
|
}
|
|
init_get_bits(&gb, buf, 20 * 8);
|
|
|
|
for (i=0; i<10; i++)
|
|
lpc_refl[i] = lpc_refl_cb[i][get_bits(&gb, sizes[i])];
|
|
|
|
eval_coefs(ractx->lpc_coef[0], lpc_refl);
|
|
ractx->lpc_refl_rms[0] = rms(lpc_refl);
|
|
|
|
energy = energy_tab[get_bits(&gb, 5)];
|
|
|
|
refl_rms[0] = interp(ractx, block_coefs[0], 1, 1, ractx->old_energy);
|
|
refl_rms[1] = interp(ractx, block_coefs[1], 2, energy <= ractx->old_energy,
|
|
t_sqrt(energy*ractx->old_energy) >> 12);
|
|
refl_rms[2] = interp(ractx, block_coefs[2], 3, 0, energy);
|
|
refl_rms[3] = rescale_rms(ractx->lpc_refl_rms[0], energy);
|
|
|
|
int_to_int16(block_coefs[3], ractx->lpc_coef[0]);
|
|
|
|
for (i=0; i < 4; i++) {
|
|
do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb);
|
|
|
|
for (j=0; j < BLOCKSIZE; j++)
|
|
*data++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2);
|
|
}
|
|
|
|
ractx->old_energy = energy;
|
|
ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0];
|
|
|
|
FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]);
|
|
|
|
*data_size = 2*160;
|
|
return 20;
|
|
}
|
|
|
|
AVCodec ra_144_decoder =
|
|
{
|
|
"real_144",
|
|
CODEC_TYPE_AUDIO,
|
|
CODEC_ID_RA_144,
|
|
sizeof(RA144Context),
|
|
ra144_decode_init,
|
|
NULL,
|
|
NULL,
|
|
ra144_decode_frame,
|
|
.long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"),
|
|
};
|