root/libavcodec/wmaenc.c

DEFINITIONS

1. encode_init
2. apply_window_and_mdct
3. init_exp
4. encode_exp_vlc
5. encode_block
6. encode_frame
7. encode_superframe

/*
 * 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 "libavutil/attributes.h"

#include "avcodec.h"
#include "internal.h"
#include "wma.h"
#include "libavutil/avassert.h"


static av_cold int encode_init(AVCodecContext *avctx)
{
    WMACodecContext *s = avctx->priv_data;
    int i, flags1, flags2, block_align;
    uint8_t *extradata;

    s->avctx = avctx;

    if (avctx->channels > MAX_CHANNELS) {
        av_log(avctx, AV_LOG_ERROR,
               "too many channels: got %i, need %i or fewer\n",
               avctx->channels, MAX_CHANNELS);
        return AVERROR(EINVAL);
    }

    if (avctx->sample_rate > 48000) {
        av_log(avctx, AV_LOG_ERROR, "sample rate is too high: %d > 48kHz\n",
               avctx->sample_rate);
        return AVERROR(EINVAL);
    }

    if (avctx->bit_rate < 24 * 1000) {
        av_log(avctx, AV_LOG_ERROR,
               "bitrate too low: got %i, need 24000 or higher\n",
               avctx->bit_rate);
        return AVERROR(EINVAL);
    }

    /* extract flag infos */
    flags1 = 0;
    flags2 = 1;
    if (avctx->codec->id == AV_CODEC_ID_WMAV1) {
        extradata             = av_malloc(4);
        if (!extradata)
            return AVERROR(ENOMEM);
        avctx->extradata_size = 4;
        AV_WL16(extradata, flags1);
        AV_WL16(extradata + 2, flags2);
    } else if (avctx->codec->id == AV_CODEC_ID_WMAV2) {
        extradata             = av_mallocz(10);
        if (!extradata)
            return AVERROR(ENOMEM);
        avctx->extradata_size = 10;
        AV_WL32(extradata, flags1);
        AV_WL16(extradata + 4, flags2);
    } else {
        av_assert0(0);
    }
    avctx->extradata          = extradata;
    s->use_exp_vlc            = flags2 & 0x0001;
    s->use_bit_reservoir      = flags2 & 0x0002;
    s->use_variable_block_len = flags2 & 0x0004;
    if (avctx->channels == 2)
        s->ms_stereo = 1;

    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);

    block_align        = avctx->bit_rate * (int64_t) s->frame_len /
                         (avctx->sample_rate * 8);
    block_align        = FFMIN(block_align, MAX_CODED_SUPERFRAME_SIZE);
    avctx->block_align = block_align;
    avctx->frame_size = avctx->initial_padding = s->frame_len;

    return 0;
}

static void apply_window_and_mdct(AVCodecContext *avctx, const AVFrame *frame)
{
    WMACodecContext *s = avctx->priv_data;
    float **audio      = (float **) frame->extended_data;
    int len            = frame->nb_samples;
    int window_index   = s->frame_len_bits - s->block_len_bits;
    FFTContext *mdct   = &s->mdct_ctx[window_index];
    int ch;
    const float *win   = s->windows[window_index];
    int window_len     = 1 << s->block_len_bits;
    float n            = 2.0 * 32768.0 / window_len;

    for (ch = 0; ch < avctx->channels; ch++) {
        memcpy(s->output, s->frame_out[ch], window_len * sizeof(*s->output));
        s->fdsp->vector_fmul_scalar(s->frame_out[ch], audio[ch], n, len);
        s->fdsp->vector_fmul_reverse(&s->output[window_len], s->frame_out[ch],
                                    win, len);
        s->fdsp->vector_fmul(s->frame_out[ch], s->frame_out[ch], win, len);
        mdct->mdct_calc(mdct, s->coefs[ch], 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++;
        av_assert0(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;
        av_assert1(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) {
        av_assert0(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;
//     av_assert0((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->avctx->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->avctx->channels == 2)
        put_bits(&s->pb, 1, !!s->ms_stereo);

    for (ch = 0; ch < s->avctx->channels; ch++) {
        // FIXME only set channel_coded when needed, instead of always
        s->channel_coded[ch] = 1;
        if (s->channel_coded[ch])
            init_exp(s, ch, fixed_exp);
    }

    for (ch = 0; ch < s->avctx->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) {
                av_assert0(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->avctx->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->avctx->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->avctx->channels; ch++) {
            if (s->channel_coded[ch]) {
                if (s->use_exp_vlc) {
                    encode_exp_vlc(s, ch, fixed_exp);
                } else {
                    av_assert0(0); // FIXME not implemented
//                    encode_exp_lsp(s, ch);
                }
            }
        }
    } else
        av_assert0(0); // FIXME not implemented

    for (ch = 0; ch < s->avctx->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];

                    av_assert2(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;

                        put_bits(&s->pb, coef_nb_bits, abs_level);
                        put_bits(&s->pb, s->frame_len_bits, run);
                    }
                    // FIXME the sign is flipped somewhere
                    put_bits(&s->pb, 1, level < 0);
                    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->avctx->channels >= 2)
            avpriv_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)
        av_assert0(0); // FIXME not implemented
    else if (encode_block(s, src_coefs, total_gain) < 0)
        return INT_MAX;

    avpriv_align_put_bits(&s->pb);

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

static int encode_superframe(AVCodecContext *avctx, AVPacket *avpkt,
                             const AVFrame *frame, int *got_packet_ptr)
{
    WMACodecContext *s = avctx->priv_data;
    int i, total_gain, ret, error;

    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, frame);

    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 ((ret = ff_alloc_packet2(avctx, avpkt, 2 * MAX_CODED_SUPERFRAME_SIZE)) < 0)
        return ret;

    total_gain = 128;
    for (i = 64; i; i >>= 1) {
        error = encode_frame(s, s->coefs, avpkt->data, avpkt->size,
                                 total_gain - i);
        if (error <= 0)
            total_gain -= i;
    }

    while(total_gain <= 128 && error > 0)
        error = encode_frame(s, s->coefs, avpkt->data, avpkt->size, total_gain++);
    if (error > 0) {
        av_log(avctx, AV_LOG_ERROR, "Invalid input data or requested bitrate too low, cannot encode\n");
        avpkt->size = 0;
        return AVERROR(EINVAL);
    }
    av_assert0((put_bits_count(&s->pb) & 7) == 0);
    i= avctx->block_align - (put_bits_count(&s->pb)+7)/8;
    av_assert0(i>=0);
    while(i--)
        put_bits(&s->pb, 8, 'N');

    flush_put_bits(&s->pb);
    av_assert0(put_bits_ptr(&s->pb) - s->pb.buf == avctx->block_align);

    if (frame->pts != AV_NOPTS_VALUE)
        avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding);

    avpkt->size     = avctx->block_align;
    *got_packet_ptr = 1;
    return 0;
}

#if CONFIG_WMAV1_ENCODER
AVCodec ff_wmav1_encoder = {
    .name           = "wmav1",
    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_WMAV1,
    .priv_data_size = sizeof(WMACodecContext),
    .init           = encode_init,
    .encode2        = encode_superframe,
    .close          = ff_wma_end,
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                      AV_SAMPLE_FMT_NONE },
};
#endif
#if CONFIG_WMAV2_ENCODER
AVCodec ff_wmav2_encoder = {
    .name           = "wmav2",
    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_WMAV2,
    .priv_data_size = sizeof(WMACodecContext),
    .init           = encode_init,
    .encode2        = encode_superframe,
    .close          = ff_wma_end,
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                      AV_SAMPLE_FMT_NONE },
};
#endif