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ffmpeg / libavcodec / wma.c @ 1890c2ac

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/*
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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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    WMACodecContext *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(s->avctx, "flags2=0x%x\n", flags2);
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    dprintf(s->avctx, "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(s->avctx, "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(s->avctx, "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(s->avctx, "%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(s->avctx, " %d", s->exponent_high_bands[k][j]);
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            tprintf(s->avctx, "\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(s->avctx, "%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(s->avctx, " %d", s->exponent_bands[i][j]);
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            tprintf(s->avctx, "\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[j] = 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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    WMACodecContext *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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}