wmv2enc.c

mediastreamer2是开源的网络传输媒体流的库

/*
 * 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 "dsputil.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 int wmv2_encode_init(AVCodecContext *avctx){
    Wmv2Context * const w= avctx->priv_data;

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

    ff_wmv2_common_init(w);

    avctx->extradata_size= 4;
    avctx->extradata= av_mallocz(avctx->extradata_size + 10);
    encode_ext_header(w);

    return 0;
}

#if 0 /* unused, remove? */
static int wmv2_encode_end(AVCodecContext *avctx){

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

    avctx->extradata_size= 0;
    av_freep(&avctx->extradata);

    return 0;
}
#endif

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 == I_TYPE){
        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->use_skip_mb_code = 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;

    assert(s->flipflop_rounding);

    if (s->pict_type == I_TYPE) {
        assert(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);
        if(s->qscale <= 10){
            int map[3]= {0,2,1};
            w->cbp_table_index= map[cbp_index];
        }else if(s->qscale <= 20){
            int map[3]= {1,0,2};
            w->cbp_table_index= map[cbp_index];
        }else{
            int map[3]= {2,1,0};
            w->cbp_table_index= map[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,
                       DCTELEM 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,
                 wmv2_inter_table[w->cbp_table_index][cbp + 64][1],
                 wmv2_inter_table[w->cbp_table_index][cbp + 64][0]);

        /* motion vector */
        h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
        ff_msmpeg4_encode_motion(s, motion_x - pred_x,
                              motion_y - pred_y);
    } 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 0
        if (coded_cbp)
            printf("cbp=%x %x\n", cbp, coded_cbp);
#endif

        if (s->pict_type == I_TYPE) {
            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,
                     wmv2_inter_table[w->cbp_table_index][cbp][1],
                     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, table_inter_intra[s->h263_aic_dir][1], table_inter_intra[s->h263_aic_dir][0]);
        }
    }

    for (i = 0; i < 6; i++) {
        ff_msmpeg4_encode_block(s, block[i], i);
    }
}

AVCodec wmv2_encoder = {
    "wmv2",
    CODEC_TYPE_VIDEO,
    CODEC_ID_WMV2,
    sizeof(Wmv2Context),
    wmv2_encode_init,
    MPV_encode_picture,
    MPV_encode_end,
    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1},
};