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ffmpeg/libavcodec/wma.c

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/*
* WMA compatible codec
* Copyright (c) 2002-2007 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"
#include "wma.h"
#include "wmadata.h"
#undef NDEBUG
#include <assert.h>
/* XXX: use same run/length optimization as mpeg decoders */
//FIXME maybe split decode / encode or pass flag
static void init_coef_vlc(VLC *vlc,
uint16_t **prun_table, uint16_t **plevel_table, uint16_t **pint_table,
const CoefVLCTable *vlc_table)
{
int n = vlc_table->n;
const uint8_t *table_bits = vlc_table->huffbits;
const uint32_t *table_codes = vlc_table->huffcodes;
const uint16_t *levels_table = vlc_table->levels;
uint16_t *run_table, *level_table, *int_table;
int i, l, j, k, level;
init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
run_table = av_malloc(n * sizeof(uint16_t));
level_table = av_malloc(n * sizeof(uint16_t));
int_table = av_malloc(n * sizeof(uint16_t));
i = 2;
level = 1;
k = 0;
while (i < n) {
int_table[k]= i;
l = levels_table[k++];
for(j=0;j<l;j++) {
run_table[i] = j;
level_table[i] = level;
i++;
}
level++;
}
*prun_table = run_table;
*plevel_table = level_table;
*pint_table= int_table;
}
int ff_wma_init(AVCodecContext * avctx, int flags2)
{
WMACodecContext *s = avctx->priv_data;
int i;
float bps1, high_freq;
volatile float bps;
int sample_rate1;
int coef_vlc_table;
if( avctx->sample_rate<=0 || avctx->sample_rate>50000
|| avctx->channels<=0 || avctx->channels>8
|| avctx->bit_rate<=0)
return -1;
s->sample_rate = avctx->sample_rate;
s->nb_channels = avctx->channels;
s->bit_rate = avctx->bit_rate;
s->block_align = avctx->block_align;
dsputil_init(&s->dsp, avctx);
if (avctx->codec->id == CODEC_ID_WMAV1) {
s->version = 1;
} else {
s->version = 2;
}
/* compute MDCT block size */
if (s->sample_rate <= 16000) {
s->frame_len_bits = 9;
} else if (s->sample_rate <= 22050 ||
(s->sample_rate <= 32000 && s->version == 1)) {
s->frame_len_bits = 10;
} else {
s->frame_len_bits = 11;
}
s->frame_len = 1 << s->frame_len_bits;
if (s->use_variable_block_len) {
int nb_max, nb;
nb = ((flags2 >> 3) & 3) + 1;
if ((s->bit_rate / s->nb_channels) >= 32000)
nb += 2;
nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
if (nb > nb_max)
nb = nb_max;
s->nb_block_sizes = nb + 1;
} else {
s->nb_block_sizes = 1;
}
/* init rate dependent parameters */
s->use_noise_coding = 1;
high_freq = s->sample_rate * 0.5;
/* if version 2, then the rates are normalized */
sample_rate1 = s->sample_rate;
if (s->version == 2) {
if (sample_rate1 >= 44100)
sample_rate1 = 44100;
else if (sample_rate1 >= 22050)
sample_rate1 = 22050;
else if (sample_rate1 >= 16000)
sample_rate1 = 16000;
else if (sample_rate1 >= 11025)
sample_rate1 = 11025;
else if (sample_rate1 >= 8000)
sample_rate1 = 8000;
}
bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
/* compute high frequency value and choose if noise coding should
be activated */
bps1 = bps;
if (s->nb_channels == 2)
bps1 = bps * 1.6;
if (sample_rate1 == 44100) {
if (bps1 >= 0.61)
s->use_noise_coding = 0;
else
high_freq = high_freq * 0.4;
} else if (sample_rate1 == 22050) {
if (bps1 >= 1.16)
s->use_noise_coding = 0;
else if (bps1 >= 0.72)
high_freq = high_freq * 0.7;
else
high_freq = high_freq * 0.6;
} else if (sample_rate1 == 16000) {
if (bps > 0.5)
high_freq = high_freq * 0.5;
else
high_freq = high_freq * 0.3;
} else if (sample_rate1 == 11025) {
high_freq = high_freq * 0.7;
} else if (sample_rate1 == 8000) {
if (bps <= 0.625) {
high_freq = high_freq * 0.5;
} else if (bps > 0.75) {
s->use_noise_coding = 0;
} else {
high_freq = high_freq * 0.65;
}
} else {
if (bps >= 0.8) {
high_freq = high_freq * 0.75;
} else if (bps >= 0.6) {
high_freq = high_freq * 0.6;
} else {
high_freq = high_freq * 0.5;
}
}
dprintf(s->avctx, "flags2=0x%x\n", flags2);
dprintf(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
s->version, s->nb_channels, s->sample_rate, s->bit_rate,
s->block_align);
dprintf(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
bps, bps1, high_freq, s->byte_offset_bits);
dprintf(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
/* compute the scale factor band sizes for each MDCT block size */
{
int a, b, pos, lpos, k, block_len, i, j, n;
const uint8_t *table;
if (s->version == 1) {
s->coefs_start = 3;
} else {
s->coefs_start = 0;
}
for(k = 0; k < s->nb_block_sizes; k++) {
block_len = s->frame_len >> k;
if (s->version == 1) {
lpos = 0;
for(i=0;i<25;i++) {
a = wma_critical_freqs[i];
b = s->sample_rate;
pos = ((block_len * 2 * a) + (b >> 1)) / b;
if (pos > block_len)
pos = block_len;
s->exponent_bands[0][i] = pos - lpos;
if (pos >= block_len) {
i++;
break;
}
lpos = pos;
}
s->exponent_sizes[0] = i;
} else {
/* hardcoded tables */
table = NULL;
a = s->frame_len_bits - BLOCK_MIN_BITS - k;
if (a < 3) {
if (s->sample_rate >= 44100)
table = exponent_band_44100[a];
else if (s->sample_rate >= 32000)
table = exponent_band_32000[a];
else if (s->sample_rate >= 22050)
table = exponent_band_22050[a];
}
if (table) {
n = *table++;
for(i=0;i<n;i++)
s->exponent_bands[k][i] = table[i];
s->exponent_sizes[k] = n;
} else {
j = 0;
lpos = 0;
for(i=0;i<25;i++) {
a = wma_critical_freqs[i];
b = s->sample_rate;
pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
pos <<= 2;
if (pos > block_len)
pos = block_len;
if (pos > lpos)
s->exponent_bands[k][j++] = pos - lpos;
if (pos >= block_len)
break;
lpos = pos;
}
s->exponent_sizes[k] = j;
}
}
/* max number of coefs */
s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
/* high freq computation */
s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
s->sample_rate + 0.5);
n = s->exponent_sizes[k];
j = 0;
pos = 0;
for(i=0;i<n;i++) {
int start, end;
start = pos;
pos += s->exponent_bands[k][i];
end = pos;
if (start < s->high_band_start[k])
start = s->high_band_start[k];
if (end > s->coefs_end[k])
end = s->coefs_end[k];
if (end > start)
s->exponent_high_bands[k][j++] = end - start;
}
s->exponent_high_sizes[k] = j;
#if 0
tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
s->frame_len >> k,
s->coefs_end[k],
s->high_band_start[k],
s->exponent_high_sizes[k]);
for(j=0;j<s->exponent_high_sizes[k];j++)
tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
tprintf(s->avctx, "\n");
#endif
}
}
#ifdef TRACE
{
int i, j;
for(i = 0; i < s->nb_block_sizes; i++) {
tprintf(s->avctx, "%5d: n=%2d:",
s->frame_len >> i,
s->exponent_sizes[i]);
for(j=0;j<s->exponent_sizes[i];j++)
tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
tprintf(s->avctx, "\n");
}
}
#endif
/* init MDCT windows : simple sinus window */
for(i = 0; i < s->nb_block_sizes; i++) {
int n;
n = 1 << (s->frame_len_bits - i);
ff_sine_window_init(ff_sine_windows[s->frame_len_bits - i - 7], n);
s->windows[i] = ff_sine_windows[s->frame_len_bits - i - 7];
}
s->reset_block_lengths = 1;
if (s->use_noise_coding) {
/* init the noise generator */
if (s->use_exp_vlc)
s->noise_mult = 0.02;
else
s->noise_mult = 0.04;
#ifdef TRACE
for(i=0;i<NOISE_TAB_SIZE;i++)
s->noise_table[i] = 1.0 * s->noise_mult;
#else
{
unsigned int seed;
float norm;
seed = 1;
norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
for(i=0;i<NOISE_TAB_SIZE;i++) {
seed = seed * 314159 + 1;
s->noise_table[i] = (float)((int)seed) * norm;
}
}
#endif
}
/* choose the VLC tables for the coefficients */
coef_vlc_table = 2;
if (s->sample_rate >= 32000) {
if (bps1 < 0.72)
coef_vlc_table = 0;
else if (bps1 < 1.16)
coef_vlc_table = 1;
}
s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2 ];
s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
s->coef_vlcs[0]);
init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
s->coef_vlcs[1]);
return 0;
}
int ff_wma_total_gain_to_bits(int total_gain){
if (total_gain < 15) return 13;
else if (total_gain < 32) return 12;
else if (total_gain < 40) return 11;
else if (total_gain < 45) return 10;
else return 9;
}
int ff_wma_end(AVCodecContext *avctx)
{
WMACodecContext *s = avctx->priv_data;
int i;
for(i = 0; i < s->nb_block_sizes; i++)
ff_mdct_end(&s->mdct_ctx[i]);
if (s->use_exp_vlc) {
free_vlc(&s->exp_vlc);
}
if (s->use_noise_coding) {
free_vlc(&s->hgain_vlc);
}
for(i = 0;i < 2; i++) {
free_vlc(&s->coef_vlc[i]);
av_free(s->run_table[i]);
av_free(s->level_table[i]);
av_free(s->int_table[i]);
}
return 0;
}
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