wmadec.c

tcpmp播放器的flv插件

/*
 * WMA compatible decoder
 * Copyright (c) 2002 The FFmpeg Project.
 *
 * This library 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 of the License, or (at your option) any later version.
 *
 * This library 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 this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/**
 * @file wmadec.c
 * WMA compatible decoder.
 * This decoder handles Microsoft Windows Media Audio data, versions 1 & 2.
 * WMA v1 is identified by audio format 0x160 in Microsoft media files 
 * (ASF/AVI/WAV). WMA v2 is identified by audio format 0x161.
 *
 * To use this decoder, a calling application must supply the extra data
 * bytes provided with the WMA data. These are the extra, codec-specific
 * bytes at the end of a WAVEFORMATEX data structure. Transmit these bytes 
 * to the decoder using the extradata[_size] fields in AVCodecContext. There 
 * should be 4 extra bytes for v1 data and 6 extra bytes for v2 data.
 */

#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"

/* size of blocks */
#define BLOCK_MIN_BITS 7
#define BLOCK_MAX_BITS 11
#define BLOCK_MAX_SIZE (1 << BLOCK_MAX_BITS)

#define BLOCK_NB_SIZES (BLOCK_MAX_BITS - BLOCK_MIN_BITS + 1)

/* XXX: find exact max size */
#define HIGH_BAND_MAX_SIZE 16

#define NB_LSP_COEFS 10

/* XXX: is it a suitable value ? */
#define MAX_CODED_SUPERFRAME_SIZE 16384

#define MAX_CHANNELS 2

#define NOISE_TAB_SIZE 8192

#define LSP_POW_BITS 7

typedef struct WMADecodeContext {
    GetBitContext gb;
    int sample_rate;
    int nb_channels;
    int bit_rate;
    int version; /* 1 = 0x160 (WMAV1), 2 = 0x161 (WMAV2) */
    int block_align;
    int use_bit_reservoir;
    int use_variable_block_len;
    int use_exp_vlc;  /* exponent coding: 0 = lsp, 1 = vlc + delta */
    int use_noise_coding; /* true if perceptual noise is added */
    int byte_offset_bits;
    VLC exp_vlc;
    int exponent_sizes[BLOCK_NB_SIZES];
    uint16_t exponent_bands[BLOCK_NB_SIZES][25];
    int high_band_start[BLOCK_NB_SIZES]; /* index of first coef in high band */
    int coefs_start;               /* first coded coef */
    int coefs_end[BLOCK_NB_SIZES]; /* max number of coded coefficients */
    int exponent_high_sizes[BLOCK_NB_SIZES];
    int exponent_high_bands[BLOCK_NB_SIZES][HIGH_BAND_MAX_SIZE]; 
    VLC hgain_vlc;
    
    /* coded values in high bands */
    int high_band_coded[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];
    int high_band_values[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];

    /* there are two possible tables for spectral coefficients */
    VLC coef_vlc[2];
    uint16_t *run_table[2];
    uint16_t *level_table[2];
    /* frame info */
    int frame_len;       /* frame length in samples */
    int frame_len_bits;  /* frame_len = 1 << frame_len_bits */
    int nb_block_sizes;  /* number of block sizes */
    /* block info */
    int reset_block_lengths;
    int block_len_bits; /* log2 of current block length */
    int next_block_len_bits; /* log2 of next block length */
    int prev_block_len_bits; /* log2 of prev block length */
    int block_len; /* block length in samples */
    int block_num; /* block number in current frame */
    int block_pos; /* current position in frame */
    uint8_t ms_stereo; /* true if mid/side stereo mode */
    uint8_t channel_coded[MAX_CHANNELS]; /* true if channel is coded */
    float exponents[MAX_CHANNELS][BLOCK_MAX_SIZE] __attribute__((aligned(16)));
    float max_exponent[MAX_CHANNELS];
    int16_t coefs1[MAX_CHANNELS][BLOCK_MAX_SIZE];
    float coefs[MAX_CHANNELS][BLOCK_MAX_SIZE] __attribute__((aligned(16)));
    MDCTContext mdct_ctx[BLOCK_NB_SIZES];
    float *windows[BLOCK_NB_SIZES];
    FFTSample mdct_tmp[BLOCK_MAX_SIZE] __attribute__((aligned(16))); /* temporary storage for imdct */
    /* output buffer for one frame and the last for IMDCT windowing */
    float frame_out[MAX_CHANNELS][BLOCK_MAX_SIZE * 2] __attribute__((aligned(16)));
    /* last frame info */
    uint8_t last_superframe[MAX_CODED_SUPERFRAME_SIZE + 4]; /* padding added */
    int last_bitoffset;
    int last_superframe_len;
    float noise_table[NOISE_TAB_SIZE];
    int noise_index;
    float noise_mult; /* XXX: suppress that and integrate it in the noise array */
    /* lsp_to_curve tables */
    float lsp_cos_table[BLOCK_MAX_SIZE];
    float lsp_pow_e_table[256];
    float lsp_pow_m_table1[(1 << LSP_POW_BITS)];
    float lsp_pow_m_table2[(1 << LSP_POW_BITS)];

#ifdef TRACE
    int frame_count;
#endif
} WMADecodeContext;

typedef struct CoefVLCTable {
    int n; /* total number of codes */
    const uint32_t *huffcodes; /* VLC bit values */
    const uint8_t *huffbits;   /* VLC bit size */
    const uint16_t *levels; /* table to build run/level tables */
} CoefVLCTable;

static void wma_lsp_to_curve_init(WMADecodeContext *s, int frame_len);

#include "wmadata.h"

#ifdef TRACE
static void dump_shorts(const char *name, const short *tab, int n)
{
    int i;

    tprintf("%s[%d]:\n", name, n);
    for(i=0;i<n;i++) {
        if ((i & 7) == 0)
            tprintf("%4d: ", i);
        tprintf(" %5d.0", tab[i]);
        if ((i & 7) == 7)
            tprintf("\n");
    }
}

static void dump_floats(const char *name, int prec, const float *tab, int n)
{
    int i;

    tprintf("%s[%d]:\n", name, n);
    for(i=0;i<n;i++) {
        if ((i & 7) == 0)
            tprintf("%4d: ", i);
        tprintf(" %8.*f", prec, tab[i]);
        if ((i & 7) == 7)
            tprintf("\n");
    }
    if ((i & 7) != 0)
        tprintf("\n");
}
#endif

/* XXX: use same run/length optimization as mpeg decoders */
static void init_coef_vlc(VLC *vlc, 
                          uint16_t **prun_table, uint16_t **plevel_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;
    const uint16_t *p;
    int i, l, j, level;

    init_vlc(vlc, 9, 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));
    p = levels_table;
    i = 2;
    level = 1;
    while (i < n) {
        l = *p++;
        for(j=0;j<l;j++) {
            run_table[i] = j;
            level_table[i] = level;
            i++;
        }
        level++;
    }
    *prun_table = run_table;
    *plevel_table = level_table;
}

static int wma_decode_init(AVCodecContext * avctx)
{
    WMADecodeContext *s = avctx->priv_data;
    int i, flags1, flags2;
    float *window;
    uint8_t *extradata;
    float bps1, high_freq;
    volatile float bps;
    int sample_rate1;
    int coef_vlc_table;
    
    s->sample_rate = avctx->sample_rate;
    s->nb_channels = avctx->channels;
    s->bit_rate = avctx->bit_rate;
    s->block_align = avctx->block_align;

    if (avctx->codec->id == CODEC_ID_WMAV1) {
        s->version = 1;
    } else {
        s->version = 2;
    }
    
    /* extract flag infos */
    flags1 = 0;
    flags2 = 0;
    extradata = avctx->extradata;
    if (s->version == 1 && avctx->extradata_size >= 4) {
        flags1 = extradata[0] | (extradata[1] << 8);
        flags2 = extradata[2] | (extradata[3] << 8);
    } else if (s->version == 2 && avctx->extradata_size >= 6) {
        flags1 = extradata[0] | (extradata[1] << 8) | 
            (extradata[2] << 16) | (extradata[3] << 24);
        flags2 = extradata[4] | (extradata[5] << 8);
    }
    s->use_exp_vlc = flags2 & 0x0001;
    s->use_bit_reservoir = flags2 & 0x0002;
    s->use_variable_block_len = flags2 & 0x0004;

    /* 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 dependant 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)) + 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("flags1=0x%x flags2=0x%x\n", flags1, flags2);
    dprintf("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("bps=%f bps1=%f high_freq=%f bitoffset=%d\n", 
           bps, bps1, high_freq, s->byte_offset_bits);
    dprintf("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("%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(" %d", s->exponent_high_bands[k][j]);
            tprintf("\n");
#endif
        }
    }

#ifdef TRACE
    {
        int i, j;
        for(i = 0; i < s->nb_block_sizes; i++) {
            tprintf("%5d: n=%2d:", 
                   s->frame_len >> i, 
                   s->exponent_sizes[i]);
            for(j=0;j<s->exponent_sizes[i];j++)