FFmpeg4/libavcodec/wmv2enc.c

/*
 * Copyright (c) 2002 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 "h263.h"
#include "mpegvideo.h"
#include "msmpeg4.h"
#include "msmpeg4data.h"
#include "wmv2.h"


static int encode_ext_header(Wmv2Context *w)
{
    MpegEncContext *const s = &w->s;
    PutBitContext pb;
    int code;

    init_put_bits(&pb, s->avctx->extradata, s->avctx->extradata_size);

    put_bits(&pb, 5, s->avctx->time_base.den / s->avctx->time_base.num); // yes 29.97 -> 29
    put_bits(&pb, 11, FFMIN(s->bit_rate / 1024, 2047));

    put_bits(&pb, 1, w->mspel_bit        = 1);
    put_bits(&pb, 1, s->loop_filter);
    put_bits(&pb, 1, w->abt_flag         = 1);
    put_bits(&pb, 1, w->j_type_bit       = 1);
    put_bits(&pb, 1, w->top_left_mv_flag = 0);
    put_bits(&pb, 1, w->per_mb_rl_bit    = 1);
    put_bits(&pb, 3, code                = 1);

    flush_put_bits(&pb);

    s->slice_height = s->mb_height / code;

    return 0;
}

static av_cold int wmv2_encode_init(AVCodecContext *avctx)
{
    Wmv2Context *const w = avctx->priv_data;

    if (ff_mpv_encode_init(avctx) < 0)
        return -1;

    ff_wmv2_common_init(w);

    avctx->extradata_size = 4;
    avctx->extradata      = av_mallocz(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
    if (!avctx->extradata)
        return AVERROR(ENOMEM);

    encode_ext_header(w);

    return 0;
}

int ff_wmv2_encode_picture_header(MpegEncContext *s, int picture_number)
{
    Wmv2Context *const w = (Wmv2Context *) s;

    put_bits(&s->pb, 1, s->pict_type - 1);
    if (s->pict_type == AV_PICTURE_TYPE_I)
        put_bits(&s->pb, 7, 0);
    put_bits(&s->pb, 5, s->qscale);

    s->dc_table_index  = 1;
    s->mv_table_index  = 1; /* only if P-frame */
    s->per_mb_rl_table = 0;
    s->mspel           = 0;
    w->per_mb_abt      = 0;
    w->abt_type        = 0;
    w->j_type          = 0;

    av_assert0(s->flipflop_rounding);

    if (s->pict_type == AV_PICTURE_TYPE_I) {
        av_assert0(s->no_rounding == 1);
        if (w->j_type_bit)
            put_bits(&s->pb, 1, w->j_type);

        if (w->per_mb_rl_bit)
            put_bits(&s->pb, 1, s->per_mb_rl_table);

        if (!s->per_mb_rl_table) {
            ff_msmpeg4_code012(&s->pb, s->rl_chroma_table_index);
            ff_msmpeg4_code012(&s->pb, s->rl_table_index);
        }

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

        s->inter_intra_pred = 0;
    } else {
        int cbp_index;

        put_bits(&s->pb, 2, SKIP_TYPE_NONE);

        ff_msmpeg4_code012(&s->pb, cbp_index = 0);
        w->cbp_table_index = wmv2_get_cbp_table_index(s, cbp_index);

        if (w->mspel_bit)
            put_bits(&s->pb, 1, s->mspel);

        if (w->abt_flag) {
            put_bits(&s->pb, 1, w->per_mb_abt ^ 1);
            if (!w->per_mb_abt)
                ff_msmpeg4_code012(&s->pb, w->abt_type);
        }

        if (w->per_mb_rl_bit)
            put_bits(&s->pb, 1, s->per_mb_rl_table);

        if (!s->per_mb_rl_table) {
            ff_msmpeg4_code012(&s->pb, s->rl_table_index);
            s->rl_chroma_table_index = s->rl_table_index;
        }
        put_bits(&s->pb, 1, s->dc_table_index);
        put_bits(&s->pb, 1, s->mv_table_index);

        s->inter_intra_pred = 0; // (s->width * s->height < 320 * 240 && s->bit_rate <= II_BITRATE);
    }
    s->esc3_level_length = 0;
    s->esc3_run_length   = 0;

    return 0;
}

/* Nearly identical to wmv1 but that is just because we do not use the
 * useless M$ crap features. It is duplicated here in case someone wants
 * to add support for these crap features. */
void ff_wmv2_encode_mb(MpegEncContext *s, int16_t block[6][64],
                       int motion_x, int motion_y)
{
    Wmv2Context *const w = (Wmv2Context *) s;
    int cbp, coded_cbp, i;
    int pred_x, pred_y;
    uint8_t *coded_block;

    ff_msmpeg4_handle_slices(s);

    if (!s->mb_intra) {
        /* compute cbp */
        cbp = 0;
        for (i = 0; i < 6; i++)
            if (s->block_last_index[i] >= 0)
                cbp |= 1 << (5 - i);

        put_bits(&s->pb,
                 ff_wmv2_inter_table[w->cbp_table_index][cbp + 64][1],
                 ff_wmv2_inter_table[w->cbp_table_index][cbp + 64][0]);

        s->misc_bits += get_bits_diff(s);
        /* motion vector */
        ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
        ff_msmpeg4_encode_motion(s, motion_x - pred_x,
                                 motion_y - pred_y);
        s->mv_bits += get_bits_diff(s);
    } else {
        /* compute cbp */
        cbp       = 0;
        coded_cbp = 0;
        for (i = 0; i < 6; i++) {
            int val, pred;
            val  = (s->block_last_index[i] >= 1);
            cbp |= val << (5 - i);
            if (i < 4) {
                /* predict value for close blocks only for luma */
                pred         = ff_msmpeg4_coded_block_pred(s, i, &coded_block);
                *coded_block = val;
                val          = val ^ pred;
            }
            coded_cbp |= val << (5 - i);
        }

        if (s->pict_type == AV_PICTURE_TYPE_I)
            put_bits(&s->pb,
                     ff_msmp4_mb_i_table[coded_cbp][1],
                     ff_msmp4_mb_i_table[coded_cbp][0]);
        else
            put_bits(&s->pb,
                     ff_wmv2_inter_table[w->cbp_table_index][cbp][1],
                     ff_wmv2_inter_table[w->cbp_table_index][cbp][0]);
        put_bits(&s->pb, 1, 0);         /* no AC prediction yet */
        if (s->inter_intra_pred) {
            s->h263_aic_dir = 0;
            put_bits(&s->pb,
                     ff_table_inter_intra[s->h263_aic_dir][1],
                     ff_table_inter_intra[s->h263_aic_dir][0]);
        }
        s->misc_bits += get_bits_diff(s);
    }

    for (i = 0; i < 6; i++)
        ff_msmpeg4_encode_block(s, block[i], i);
    if (s->mb_intra)
        s->i_tex_bits += get_bits_diff(s);
    else
        s->p_tex_bits += get_bits_diff(s);
}

static const AVClass wmv2_class = {
    .class_name = "wmv2 encoder",
    .item_name  = av_default_item_name,
    .option     = ff_mpv_generic_options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_wmv2_encoder = {
    .name           = "wmv2",
    .long_name      = NULL_IF_CONFIG_SMALL("Windows Media Video 8"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_WMV2,
    .priv_data_size = sizeof(Wmv2Context),
    .priv_class     = &wmv2_class,
    .init           = wmv2_encode_init,
    .encode2        = ff_mpv_encode_picture,
    .close          = ff_mpv_encode_end,
    .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
                                                     AV_PIX_FMT_NONE },
};