PeerStreamer

/*

 * 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,

                          float **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;

    float *flevel_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));

    flevel_table= av_malloc(n * sizeof(*flevel_table));

    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;

            flevel_table[i]= level;

            i++;

        }

        level++;

    }

    *prun_table   = run_table;

    *plevel_table = flevel_table;

    *pint_table   = int_table;

    av_free(level_table);

}

/**

 *@brief Get the samples per frame for this stream.

 *@param sample_rate output sample_rate

 *@param version wma version

 *@param decode_flags codec compression features

 *@return log2 of the number of output samples per frame

 */

int av_cold ff_wma_get_frame_len_bits(int sample_rate, int version,

                                      unsigned int decode_flags)

{

    int frame_len_bits;

    if (sample_rate <= 16000) {

        frame_len_bits = 9;

    } else if (sample_rate <= 22050 ||

             (sample_rate <= 32000 && version == 1)) {

        frame_len_bits = 10;

    } else if (sample_rate <= 48000) {

        frame_len_bits = 11;

    } else if (sample_rate <= 96000) {

        frame_len_bits = 12;

    } else {

        frame_len_bits = 13;

    }

    if (version == 3) {

        int tmp = decode_flags & 0x6;

        if (tmp == 0x2) {

            ++frame_len_bits;

        } else if (tmp == 0x4) {

            --frame_len_bits;

        } else if (tmp == 0x6) {

            frame_len_bits -= 2;

        }

    }

    return frame_len_bits;

}

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 */

    s->frame_len_bits = ff_wma_get_frame_len_bits(s->sample_rate, s->version, 0);

    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 = ff_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 = ff_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++) {

        ff_init_ff_sine_windows(s->frame_len_bits - i);

        s->windows[i] = ff_sine_windows[s->frame_len_bits - i];

    }

    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;

}

/**

 * Decode an uncompressed coefficient.

 * @param gb GetBitContext

 * @return the decoded coefficient

 */

unsigned int ff_wma_get_large_val(GetBitContext* gb)

{

    /** consumes up to 34 bits */

    int n_bits = 8;

    /** decode length */

    if (get_bits1(gb)) {

        n_bits += 8;

        if (get_bits1(gb)) {

            n_bits += 8;

            if (get_bits1(gb)) {

                n_bits += 7;

            }

        }

    }

    return get_bits_long(gb, n_bits);

}

/**

 * Decode run level compressed coefficients.

 * @param avctx codec context

 * @param gb bitstream reader context

 * @param vlc vlc table for get_vlc2

 * @param level_table level codes

 * @param run_table run codes

 * @param version 0 for wma1,2 1 for wmapro

 * @param ptr output buffer

 * @param offset offset in the output buffer

 * @param num_coefs number of input coefficents

 * @param block_len input buffer length (2^n)

 * @param frame_len_bits number of bits for escaped run codes

 * @param coef_nb_bits number of bits for escaped level codes

 * @return 0 on success, -1 otherwise

 */

int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,

                            VLC *vlc,

                            const float *level_table, const uint16_t *run_table,

                            int version, WMACoef *ptr, int offset,

                            int num_coefs, int block_len, int frame_len_bits,

                            int coef_nb_bits)

{

    int code, level, sign;

    const uint32_t *ilvl = (const uint32_t*)level_table;

    uint32_t *iptr = (uint32_t*)ptr;

    const unsigned int coef_mask = block_len - 1;

    for (; offset < num_coefs; offset++) {

        code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);

        if (code > 1) {

            /** normal code */

            offset += run_table[code];

            sign = get_bits1(gb) - 1;

            iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;

        } else if (code == 1) {

            /** EOB */

            break;

        } else {

            /** escape */

            if (!version) {

                level = get_bits(gb, coef_nb_bits);

                /** NOTE: this is rather suboptimal. reading

                    block_len_bits would be better */

                offset += get_bits(gb, frame_len_bits);

            } else {

                level = ff_wma_get_large_val(gb);

                /** escape decode */

                if (get_bits1(gb)) {

                    if (get_bits1(gb)) {

                        if (get_bits1(gb)) {

                            av_log(avctx,AV_LOG_ERROR,

                                "broken escape sequence\n");

                            return -1;

                        } else

                            offset += get_bits(gb, frame_len_bits) + 4;

                    } else

                        offset += get_bits(gb, 2) + 1;

                }

            }

            sign = get_bits1(gb) - 1;

            ptr[offset & coef_mask] = (level^sign) - sign;

        }

    }

    /** NOTE: EOB can be omitted */

    if (offset > num_coefs) {

        av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");

        return -1;

    }

    return 0;

}