PeerStreamer

/*

 * WMA compatible encoder

 * Copyright (c) 2007 Michael Niedermayer

 *

 * 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"

#undef NDEBUG

#include <assert.h>

static int encode_init(AVCodecContext * avctx){

    WMACodecContext *s = avctx->priv_data;

    int i, flags1, flags2;

    uint8_t *extradata;

    s->avctx = avctx;

    if(avctx->channels > MAX_CHANNELS)

        return -1;

    if(avctx->bit_rate < 24*1000)

        return -1;

    /* extract flag infos */

    flags1 = 0;

    flags2 = 1;

    if (avctx->codec->id == CODEC_ID_WMAV1) {

        extradata= av_malloc(4);

        avctx->extradata_size= 4;

        AV_WL16(extradata, flags1);

        AV_WL16(extradata+2, flags2);

    } else if (avctx->codec->id == CODEC_ID_WMAV2) {

        extradata= av_mallocz(10);

        avctx->extradata_size= 10;

        AV_WL32(extradata, flags1);

        AV_WL16(extradata+4, flags2);

    }else

        assert(0);

    avctx->extradata= extradata;

    s->use_exp_vlc = flags2 & 0x0001;

    s->use_bit_reservoir = flags2 & 0x0002;

    s->use_variable_block_len = flags2 & 0x0004;

    ff_wma_init(avctx, flags2);

    /* init MDCT */

    for(i = 0; i < s->nb_block_sizes; i++)

        ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 0, 1.0);

    avctx->block_align=

    s->block_align= avctx->bit_rate*(int64_t)s->frame_len / (avctx->sample_rate*8);

//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d\n", s->block_align, avctx->bit_rate, s->frame_len, avctx->sample_rate);

    avctx->frame_size= s->frame_len;

    return 0;

}

static void apply_window_and_mdct(AVCodecContext * avctx, const signed short * audio, int len) {

    WMACodecContext *s = avctx->priv_data;

    int window_index= s->frame_len_bits - s->block_len_bits;

    int i, j, channel;

    const float * win = s->windows[window_index];

    int window_len = 1 << s->block_len_bits;

    float n = window_len/2;

    for (channel = 0; channel < avctx->channels; channel++) {

        memcpy(s->output, s->frame_out[channel], sizeof(float)*window_len);

        j = channel;

        for (i = 0; i < len; i++, j += avctx->channels){

            s->output[i+window_len]  = audio[j] / n * win[window_len - i - 1];

            s->frame_out[channel][i] = audio[j] / n * win[i];

        }

        ff_mdct_calc(&s->mdct_ctx[window_index], s->coefs[channel], s->output);

    }

}

//FIXME use for decoding too

static void init_exp(WMACodecContext *s, int ch, const int *exp_param){

    int n;

    const uint16_t *ptr;

    float v, *q, max_scale, *q_end;

    ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];

    q = s->exponents[ch];

    q_end = q + s->block_len;

    max_scale = 0;

    while (q < q_end) {

        /* XXX: use a table */

        v = pow(10, *exp_param++ * (1.0 / 16.0));

        max_scale= FFMAX(max_scale, v);

        n = *ptr++;

        do {

            *q++ = v;

        } while (--n);

    }

    s->max_exponent[ch] = max_scale;

}

static void encode_exp_vlc(WMACodecContext *s, int ch, const int *exp_param){

    int last_exp;

    const uint16_t *ptr;

    float *q, *q_end;

    ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];

    q = s->exponents[ch];

    q_end = q + s->block_len;

    if (s->version == 1) {

        last_exp= *exp_param++;

        assert(last_exp-10 >= 0 && last_exp-10 < 32);

        put_bits(&s->pb, 5, last_exp - 10);

        q+= *ptr++;

    }else

        last_exp = 36;

    while (q < q_end) {

        int exp = *exp_param++;

        int code = exp - last_exp + 60;

        assert(code >= 0 && code < 120);

        put_bits(&s->pb, ff_aac_scalefactor_bits[code], ff_aac_scalefactor_code[code]);

        /* XXX: use a table */

        q+= *ptr++;

        last_exp= exp;

    }

}

static int encode_block(WMACodecContext *s, float (*src_coefs)[BLOCK_MAX_SIZE], int total_gain){

    int v, bsize, ch, coef_nb_bits, parse_exponents;

    float mdct_norm;

    int nb_coefs[MAX_CHANNELS];

    static const int fixed_exp[25]={20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20};

    //FIXME remove duplication relative to decoder

    if (s->use_variable_block_len) {

        assert(0); //FIXME not implemented

    }else{

        /* fixed block len */

        s->next_block_len_bits = s->frame_len_bits;

        s->prev_block_len_bits = s->frame_len_bits;

        s->block_len_bits = s->frame_len_bits;

    }

    s->block_len = 1 << s->block_len_bits;

//     assert((s->block_pos + s->block_len) <= s->frame_len);

    bsize = s->frame_len_bits - s->block_len_bits;

    //FIXME factor

    v = s->coefs_end[bsize] - s->coefs_start;

    for(ch = 0; ch < s->nb_channels; ch++)

        nb_coefs[ch] = v;

    {

        int n4 = s->block_len / 2;

        mdct_norm = 1.0 / (float)n4;

        if (s->version == 1) {

            mdct_norm *= sqrt(n4);

        }

    }

    if (s->nb_channels == 2) {

        put_bits(&s->pb, 1, s->ms_stereo= 1);

    }

    for(ch = 0; ch < s->nb_channels; ch++) {

        s->channel_coded[ch] = 1; //FIXME only set channel_coded when needed, instead of always

        if (s->channel_coded[ch]) {

            init_exp(s, ch, fixed_exp);

        }

    }

    for(ch = 0; ch < s->nb_channels; ch++) {

        if (s->channel_coded[ch]) {

            WMACoef *coefs1;

            float *coefs, *exponents, mult;

            int i, n;

            coefs1 = s->coefs1[ch];

            exponents = s->exponents[ch];

            mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];

            mult *= mdct_norm;

            coefs = src_coefs[ch];

            if (s->use_noise_coding && 0) {

                assert(0); //FIXME not implemented

            } else {

                coefs += s->coefs_start;

                n = nb_coefs[ch];

                for(i = 0;i < n; i++){

                    double t= *coefs++ / (exponents[i] * mult);

                    if(t<-32768 || t>32767)

                        return -1;

                    coefs1[i] = lrint(t);

                }

            }

        }

    }

    v = 0;

    for(ch = 0; ch < s->nb_channels; ch++) {

        int a = s->channel_coded[ch];

        put_bits(&s->pb, 1, a);

        v |= a;

    }

    if (!v)

        return 1;

    for(v= total_gain-1; v>=127; v-= 127)

        put_bits(&s->pb, 7, 127);

    put_bits(&s->pb, 7, v);

    coef_nb_bits= ff_wma_total_gain_to_bits(total_gain);

    if (s->use_noise_coding) {

        for(ch = 0; ch < s->nb_channels; ch++) {

            if (s->channel_coded[ch]) {

                int i, n;

                n = s->exponent_high_sizes[bsize];

                for(i=0;i<n;i++) {

                    put_bits(&s->pb, 1, s->high_band_coded[ch][i]= 0);

                    if (0)

                        nb_coefs[ch] -= s->exponent_high_bands[bsize][i];

                }

            }

        }

    }

    parse_exponents = 1;

    if (s->block_len_bits != s->frame_len_bits) {

        put_bits(&s->pb, 1, parse_exponents);

    }

    if (parse_exponents) {

        for(ch = 0; ch < s->nb_channels; ch++) {

            if (s->channel_coded[ch]) {

                if (s->use_exp_vlc) {

                    encode_exp_vlc(s, ch, fixed_exp);

                } else {

                    assert(0); //FIXME not implemented

//                    encode_exp_lsp(s, ch);

                }

            }

        }

    } else {

        assert(0); //FIXME not implemented

    }

    for(ch = 0; ch < s->nb_channels; ch++) {

        if (s->channel_coded[ch]) {

            int run, tindex;

            WMACoef *ptr, *eptr;

            tindex = (ch == 1 && s->ms_stereo);

            ptr = &s->coefs1[ch][0];

            eptr = ptr + nb_coefs[ch];

            run=0;

            for(;ptr < eptr; ptr++){

                if(*ptr){

                    int level= *ptr;

                    int abs_level= FFABS(level);

                    int code= 0;

                    if(abs_level <= s->coef_vlcs[tindex]->max_level){

                        if(run < s->coef_vlcs[tindex]->levels[abs_level-1])

                            code= run + s->int_table[tindex][abs_level-1];

                    }

                    assert(code < s->coef_vlcs[tindex]->n);

                    put_bits(&s->pb, s->coef_vlcs[tindex]->huffbits[code], s->coef_vlcs[tindex]->huffcodes[code]);

                    if(code == 0){

                        if(1<<coef_nb_bits <= abs_level)

                            return -1;

                        //Workaround minor rounding differences for the regression tests, FIXME we should find and replace the problematic float by fixpoint for reg tests

                        if(abs_level == 0x71B && (s->avctx->flags & CODEC_FLAG_BITEXACT)) abs_level=0x71A;

                        put_bits(&s->pb, coef_nb_bits, abs_level);

                        put_bits(&s->pb, s->frame_len_bits, run);

                    }

                    put_bits(&s->pb, 1, level < 0); //FIXME the sign is fliped somewhere

                    run=0;

                }else{

                    run++;

                }

            }

            if(run)

                put_bits(&s->pb, s->coef_vlcs[tindex]->huffbits[1], s->coef_vlcs[tindex]->huffcodes[1]);

        }

        if (s->version == 1 && s->nb_channels >= 2) {

            align_put_bits(&s->pb);

        }

    }

    return 0;

}

static int encode_frame(WMACodecContext *s, float (*src_coefs)[BLOCK_MAX_SIZE], uint8_t *buf, int buf_size, int total_gain){

    init_put_bits(&s->pb, buf, buf_size);

    if (s->use_bit_reservoir) {

        assert(0);//FIXME not implemented

    }else{

        if(encode_block(s, src_coefs, total_gain) < 0)

            return INT_MAX;

    }

    align_put_bits(&s->pb);

    return put_bits_count(&s->pb)/8 - s->block_align;

}

static int encode_superframe(AVCodecContext *avctx,

                            unsigned char *buf, int buf_size, void *data){

    WMACodecContext *s = avctx->priv_data;

    const short *samples = data;

    int i, total_gain;

    s->block_len_bits= s->frame_len_bits; //required by non variable block len

    s->block_len = 1 << s->block_len_bits;

    apply_window_and_mdct(avctx, samples, avctx->frame_size);

    if (s->ms_stereo) {

        float a, b;

        int i;

        for(i = 0; i < s->block_len; i++) {

            a = s->coefs[0][i]*0.5;

            b = s->coefs[1][i]*0.5;

            s->coefs[0][i] = a + b;

            s->coefs[1][i] = a - b;

        }

    }

#if 1

    total_gain= 128;

    for(i=64; i; i>>=1){

        int error= encode_frame(s, s->coefs, buf, buf_size, total_gain-i);

        if(error<0)

            total_gain-= i;

    }

#else

    total_gain= 90;

    best= encode_frame(s, s->coefs, buf, buf_size, total_gain);

    for(i=32; i; i>>=1){

        int scoreL= encode_frame(s, s->coefs, buf, buf_size, total_gain-i);

        int scoreR= encode_frame(s, s->coefs, buf, buf_size, total_gain+i);

        av_log(NULL, AV_LOG_ERROR, "%d %d %d (%d)\n", scoreL, best, scoreR, total_gain);

        if(scoreL < FFMIN(best, scoreR)){

            best = scoreL;

            total_gain -= i;

        }else if(scoreR < best){

            best = scoreR;

            total_gain += i;

        }

    }

#endif

    encode_frame(s, s->coefs, buf, buf_size, total_gain);

    assert((put_bits_count(&s->pb) & 7) == 0);

    i= s->block_align - (put_bits_count(&s->pb)+7)/8;

    assert(i>=0);

    while(i--)

        put_bits(&s->pb, 8, 'N');

    flush_put_bits(&s->pb);

    return put_bits_ptr(&s->pb) - s->pb.buf;

}

AVCodec ff_wmav1_encoder =

{

    "wmav1",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_WMAV1,

    sizeof(WMACodecContext),

    encode_init,

    encode_superframe,

    ff_wma_end,

    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},

    .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"),

};

AVCodec ff_wmav2_encoder =

{

    "wmav2",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_WMAV2,

    sizeof(WMACodecContext),

    encode_init,

    encode_superframe,

    ff_wma_end,

    .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},

    .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"),

};