Function encode_init

libavcodec/mpeg4videoenc.c:1225–1285

}

static av_cold int encode_init(AVCodecContext *avctx)
{
    static AVOnce init_static_once = AV_ONCE_INIT;
    Mpeg4EncContext *const m4 = avctx->priv_data;
    MPVMainEncContext *const m = &m4->m;
    MPVEncContext *const s = &m->s;
    int ret;

    if (avctx->width >= (1<<13) || avctx->height >= (1<<13)) {
        av_log(avctx, AV_LOG_ERROR, "dimensions too large for MPEG-4\n");
        return AVERROR(EINVAL);
    }

    m->encode_picture_header = mpeg4_encode_picture_header;
    s->encode_mb             = mpeg4_encode_mb;

    m->fcode_tab                = fcode_tab + MAX_MV;

    s->min_qcoeff               = -2048;
    s->max_qcoeff               = 2047;
    s->intra_ac_vlc_length      = uni_mpeg4_intra_rl_len;
    s->intra_ac_vlc_last_length = uni_mpeg4_intra_rl_len + 128 * 64;
    s->inter_ac_vlc_length      = uni_mpeg4_inter_rl_len;
    s->inter_ac_vlc_last_length = uni_mpeg4_inter_rl_len + 128 * 64;
    s->luma_dc_vlc_length       = uni_DCtab_lum_len;
    s->ac_esc_length            = 7 + 2 + 1 + 6 + 1 + 12 + 1;
    s->c.y_dc_scale_table         = ff_mpeg4_y_dc_scale_table;
    s->c.c_dc_scale_table         = ff_mpeg4_c_dc_scale_table;

    ff_qpeldsp_init(&s->c.qdsp);
    if ((ret = ff_mpv_encode_init(avctx)) < 0)
        return ret;

    ff_thread_once(&init_static_once, mpeg4_encode_init_static);

    if (avctx->time_base.den > (1 << 16) - 1) {
        av_log(avctx, AV_LOG_ERROR,
               "timebase %d/%d not supported by MPEG 4 standard, "
               "the maximum admitted value for the timebase denominator "
               "is %d\n", avctx->time_base.num, avctx->time_base.den,
               (1 << 16) - 1);
        return AVERROR(EINVAL);
    }

    m4->time_increment_bits     = av_log2(avctx->time_base.den - 1) + 1;

    if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {
        avctx->extradata = av_malloc(1024);
        if (!avctx->extradata)
            return AVERROR(ENOMEM);
        init_put_bits(&s->pb, avctx->extradata, 1024);

        mpeg4_encode_visual_object_header(m);
        mpeg4_encode_vol_header(m4, 0, 0);

//            ff_mpeg4_stuffing(&s->pb); ?
        flush_put_bits(&s->pb);
        avctx->extradata_size = put_bytes_output(&s->pb);