mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-16 04:15:05 +00:00
387 lines
12 KiB
C
387 lines
12 KiB
C
/*
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* WMA compatible codec
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* Copyright (c) 2002-2007 The FFmpeg Project.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "wma.h"
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#include "wmadata.h"
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#undef NDEBUG
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#include <assert.h>
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/* XXX: use same run/length optimization as mpeg decoders */
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//FIXME maybe split decode / encode or pass flag
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static void init_coef_vlc(VLC *vlc,
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uint16_t **prun_table, uint16_t **plevel_table, uint16_t **pint_table,
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const CoefVLCTable *vlc_table)
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{
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int n = vlc_table->n;
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const uint8_t *table_bits = vlc_table->huffbits;
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const uint32_t *table_codes = vlc_table->huffcodes;
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const uint16_t *levels_table = vlc_table->levels;
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uint16_t *run_table, *level_table, *int_table;
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int i, l, j, k, level;
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init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
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run_table = av_malloc(n * sizeof(uint16_t));
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level_table = av_malloc(n * sizeof(uint16_t));
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int_table = av_malloc(n * sizeof(uint16_t));
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i = 2;
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level = 1;
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k = 0;
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while (i < n) {
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int_table[k]= i;
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l = levels_table[k++];
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for(j=0;j<l;j++) {
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run_table[i] = j;
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level_table[i] = level;
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i++;
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}
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level++;
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}
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*prun_table = run_table;
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*plevel_table = level_table;
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*pint_table= int_table;
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}
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int ff_wma_init(AVCodecContext * avctx, int flags2)
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{
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WMADecodeContext *s = avctx->priv_data;
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int i;
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float *window;
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float bps1, high_freq;
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volatile float bps;
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int sample_rate1;
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int coef_vlc_table;
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s->sample_rate = avctx->sample_rate;
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s->nb_channels = avctx->channels;
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s->bit_rate = avctx->bit_rate;
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s->block_align = avctx->block_align;
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dsputil_init(&s->dsp, avctx);
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if (avctx->codec->id == CODEC_ID_WMAV1) {
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s->version = 1;
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} else {
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s->version = 2;
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}
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/* compute MDCT block size */
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if (s->sample_rate <= 16000) {
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s->frame_len_bits = 9;
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} else if (s->sample_rate <= 22050 ||
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(s->sample_rate <= 32000 && s->version == 1)) {
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s->frame_len_bits = 10;
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} else {
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s->frame_len_bits = 11;
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}
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s->frame_len = 1 << s->frame_len_bits;
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if (s->use_variable_block_len) {
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int nb_max, nb;
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nb = ((flags2 >> 3) & 3) + 1;
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if ((s->bit_rate / s->nb_channels) >= 32000)
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nb += 2;
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nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
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if (nb > nb_max)
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nb = nb_max;
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s->nb_block_sizes = nb + 1;
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} else {
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s->nb_block_sizes = 1;
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}
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/* init rate dependent parameters */
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s->use_noise_coding = 1;
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high_freq = s->sample_rate * 0.5;
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/* if version 2, then the rates are normalized */
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sample_rate1 = s->sample_rate;
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if (s->version == 2) {
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if (sample_rate1 >= 44100)
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sample_rate1 = 44100;
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else if (sample_rate1 >= 22050)
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sample_rate1 = 22050;
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else if (sample_rate1 >= 16000)
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sample_rate1 = 16000;
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else if (sample_rate1 >= 11025)
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sample_rate1 = 11025;
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else if (sample_rate1 >= 8000)
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sample_rate1 = 8000;
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}
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bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
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s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
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/* compute high frequency value and choose if noise coding should
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be activated */
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bps1 = bps;
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if (s->nb_channels == 2)
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bps1 = bps * 1.6;
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if (sample_rate1 == 44100) {
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if (bps1 >= 0.61)
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s->use_noise_coding = 0;
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else
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high_freq = high_freq * 0.4;
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} else if (sample_rate1 == 22050) {
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if (bps1 >= 1.16)
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s->use_noise_coding = 0;
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else if (bps1 >= 0.72)
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high_freq = high_freq * 0.7;
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else
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high_freq = high_freq * 0.6;
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} else if (sample_rate1 == 16000) {
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if (bps > 0.5)
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high_freq = high_freq * 0.5;
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else
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high_freq = high_freq * 0.3;
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} else if (sample_rate1 == 11025) {
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high_freq = high_freq * 0.7;
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} else if (sample_rate1 == 8000) {
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if (bps <= 0.625) {
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high_freq = high_freq * 0.5;
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} else if (bps > 0.75) {
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s->use_noise_coding = 0;
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} else {
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high_freq = high_freq * 0.65;
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}
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} else {
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if (bps >= 0.8) {
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high_freq = high_freq * 0.75;
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} else if (bps >= 0.6) {
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high_freq = high_freq * 0.6;
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} else {
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high_freq = high_freq * 0.5;
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}
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}
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dprintf("flags1=0x%x flags2=0x%x\n", flags1, flags2);
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dprintf("version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
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s->version, s->nb_channels, s->sample_rate, s->bit_rate,
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s->block_align);
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dprintf("bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
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bps, bps1, high_freq, s->byte_offset_bits);
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dprintf("use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
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s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
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/* compute the scale factor band sizes for each MDCT block size */
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{
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int a, b, pos, lpos, k, block_len, i, j, n;
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const uint8_t *table;
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if (s->version == 1) {
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s->coefs_start = 3;
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} else {
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s->coefs_start = 0;
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}
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for(k = 0; k < s->nb_block_sizes; k++) {
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block_len = s->frame_len >> k;
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if (s->version == 1) {
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lpos = 0;
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for(i=0;i<25;i++) {
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a = wma_critical_freqs[i];
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b = s->sample_rate;
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pos = ((block_len * 2 * a) + (b >> 1)) / b;
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if (pos > block_len)
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pos = block_len;
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s->exponent_bands[0][i] = pos - lpos;
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if (pos >= block_len) {
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i++;
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break;
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}
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lpos = pos;
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}
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s->exponent_sizes[0] = i;
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} else {
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/* hardcoded tables */
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table = NULL;
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a = s->frame_len_bits - BLOCK_MIN_BITS - k;
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if (a < 3) {
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if (s->sample_rate >= 44100)
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table = exponent_band_44100[a];
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else if (s->sample_rate >= 32000)
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table = exponent_band_32000[a];
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else if (s->sample_rate >= 22050)
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table = exponent_band_22050[a];
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}
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if (table) {
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n = *table++;
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for(i=0;i<n;i++)
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s->exponent_bands[k][i] = table[i];
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s->exponent_sizes[k] = n;
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} else {
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j = 0;
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lpos = 0;
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for(i=0;i<25;i++) {
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a = wma_critical_freqs[i];
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b = s->sample_rate;
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pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
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pos <<= 2;
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if (pos > block_len)
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pos = block_len;
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if (pos > lpos)
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s->exponent_bands[k][j++] = pos - lpos;
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if (pos >= block_len)
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break;
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lpos = pos;
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}
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s->exponent_sizes[k] = j;
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}
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}
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/* max number of coefs */
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s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
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/* high freq computation */
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s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
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s->sample_rate + 0.5);
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n = s->exponent_sizes[k];
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j = 0;
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pos = 0;
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for(i=0;i<n;i++) {
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int start, end;
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start = pos;
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pos += s->exponent_bands[k][i];
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end = pos;
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if (start < s->high_band_start[k])
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start = s->high_band_start[k];
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if (end > s->coefs_end[k])
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end = s->coefs_end[k];
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if (end > start)
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s->exponent_high_bands[k][j++] = end - start;
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}
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s->exponent_high_sizes[k] = j;
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#if 0
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tprintf("%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
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s->frame_len >> k,
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s->coefs_end[k],
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s->high_band_start[k],
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s->exponent_high_sizes[k]);
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for(j=0;j<s->exponent_high_sizes[k];j++)
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tprintf(" %d", s->exponent_high_bands[k][j]);
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tprintf("\n");
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#endif
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}
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}
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#ifdef TRACE
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{
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int i, j;
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for(i = 0; i < s->nb_block_sizes; i++) {
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tprintf("%5d: n=%2d:",
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s->frame_len >> i,
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s->exponent_sizes[i]);
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for(j=0;j<s->exponent_sizes[i];j++)
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tprintf(" %d", s->exponent_bands[i][j]);
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tprintf("\n");
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}
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}
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#endif
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/* init MDCT windows : simple sinus window */
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for(i = 0; i < s->nb_block_sizes; i++) {
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int n, j;
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float alpha;
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n = 1 << (s->frame_len_bits - i);
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window = av_malloc(sizeof(float) * n);
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alpha = M_PI / (2.0 * n);
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for(j=0;j<n;j++) {
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window[n - j - 1] = sin((j + 0.5) * alpha);
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}
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s->windows[i] = window;
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}
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s->reset_block_lengths = 1;
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if (s->use_noise_coding) {
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/* init the noise generator */
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if (s->use_exp_vlc)
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s->noise_mult = 0.02;
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else
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s->noise_mult = 0.04;
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#ifdef TRACE
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for(i=0;i<NOISE_TAB_SIZE;i++)
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s->noise_table[i] = 1.0 * s->noise_mult;
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#else
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{
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unsigned int seed;
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float norm;
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seed = 1;
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norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
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for(i=0;i<NOISE_TAB_SIZE;i++) {
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seed = seed * 314159 + 1;
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s->noise_table[i] = (float)((int)seed) * norm;
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}
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}
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#endif
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}
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/* choose the VLC tables for the coefficients */
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coef_vlc_table = 2;
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if (s->sample_rate >= 32000) {
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if (bps1 < 0.72)
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coef_vlc_table = 0;
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else if (bps1 < 1.16)
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coef_vlc_table = 1;
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}
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s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2 ];
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s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
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init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
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s->coef_vlcs[0]);
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init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
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s->coef_vlcs[1]);
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return 0;
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}
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int ff_wma_total_gain_to_bits(int total_gain){
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if (total_gain < 15) return 13;
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else if (total_gain < 32) return 12;
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else if (total_gain < 40) return 11;
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else if (total_gain < 45) return 10;
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else return 9;
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}
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int ff_wma_end(AVCodecContext *avctx)
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{
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WMADecodeContext *s = avctx->priv_data;
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int i;
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for(i = 0; i < s->nb_block_sizes; i++)
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ff_mdct_end(&s->mdct_ctx[i]);
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for(i = 0; i < s->nb_block_sizes; i++)
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av_free(s->windows[i]);
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if (s->use_exp_vlc) {
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free_vlc(&s->exp_vlc);
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}
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if (s->use_noise_coding) {
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free_vlc(&s->hgain_vlc);
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}
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for(i = 0;i < 2; i++) {
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free_vlc(&s->coef_vlc[i]);
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av_free(s->run_table[i]);
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av_free(s->level_table[i]);
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}
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return 0;
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}
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