asv1.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    if(a->pb.buf_end - a->pb.buf - (put_bits_count(&a->pb)>>3) < 30*16*16*3/2/8){
        av_log(a->avctx, AV_LOG_ERROR, "encoded frame too large\n");
        return -1;
    }

    if(a->avctx->codec_id == CODEC_ID_ASV1){
        for(i=0; i<6; i++)
            asv1_encode_block(a, block[i]);
    }else{
        for(i=0; i<6; i++)
            asv2_encode_block(a, block[i]);
    }
    return 0;
}

static inline void idct_put(ASV1Context *a, int mb_x, int mb_y){
    DCTELEM (*block)[64]= a->block;
    int linesize= a->picture.linesize[0];

    uint8_t *dest_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
    uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
    uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;

    a->dsp.idct_put(dest_y                 , linesize, block[0]);
    a->dsp.idct_put(dest_y              + 8, linesize, block[1]);
    a->dsp.idct_put(dest_y + 8*linesize    , linesize, block[2]);
    a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);

    if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
        a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
        a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
    }
}

static inline void dct_get(ASV1Context *a, int mb_x, int mb_y){
    DCTELEM (*block)[64]= a->block;
    int linesize= a->picture.linesize[0];
    int i;

    uint8_t *ptr_y  = a->picture.data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
    uint8_t *ptr_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
    uint8_t *ptr_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;

    a->dsp.get_pixels(block[0], ptr_y                 , linesize);
    a->dsp.get_pixels(block[1], ptr_y              + 8, linesize);
    a->dsp.get_pixels(block[2], ptr_y + 8*linesize    , linesize);
    a->dsp.get_pixels(block[3], ptr_y + 8*linesize + 8, linesize);
    for(i=0; i<4; i++)
        a->dsp.fdct(block[i]);

    if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
        a->dsp.get_pixels(block[4], ptr_cb, a->picture.linesize[1]);
        a->dsp.get_pixels(block[5], ptr_cr, a->picture.linesize[2]);
        for(i=4; i<6; i++)
            a->dsp.fdct(block[i]);
    }
}

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *data_size,
                        uint8_t *buf, int buf_size)
{
    ASV1Context * const a = avctx->priv_data;
    AVFrame *picture = data;
    AVFrame * const p= (AVFrame*)&a->picture;
    int mb_x, mb_y;

    if(p->data[0])
        avctx->release_buffer(avctx, p);

    p->reference= 0;
    if(avctx->get_buffer(avctx, p) < 0){
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }
    p->pict_type= I_TYPE;
    p->key_frame= 1;

    a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

    if(avctx->codec_id == CODEC_ID_ASV1)
        a->dsp.bswap_buf((uint32_t*)a->bitstream_buffer, (uint32_t*)buf, buf_size/4);
    else{
        int i;
        for(i=0; i<buf_size; i++)
            a->bitstream_buffer[i]= ff_reverse[ buf[i] ];
    }

    init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);

    for(mb_y=0; mb_y<a->mb_height2; mb_y++){
        for(mb_x=0; mb_x<a->mb_width2; mb_x++){
            if( decode_mb(a, a->block) <0)
                return -1;

            idct_put(a, mb_x, mb_y);
        }
    }

    if(a->mb_width2 != a->mb_width){
        mb_x= a->mb_width2;
        for(mb_y=0; mb_y<a->mb_height2; mb_y++){
            if( decode_mb(a, a->block) <0)
                return -1;

            idct_put(a, mb_x, mb_y);
        }
    }

    if(a->mb_height2 != a->mb_height){
        mb_y= a->mb_height2;
        for(mb_x=0; mb_x<a->mb_width; mb_x++){
            if( decode_mb(a, a->block) <0)
                return -1;

            idct_put(a, mb_x, mb_y);
        }
    }
#if 0
int i;
printf("%d %d\n", 8*buf_size, get_bits_count(&a->gb));
for(i=get_bits_count(&a->gb); i<8*buf_size; i++){
    printf("%d", get_bits1(&a->gb));
}

for(i=0; i<s->avctx->extradata_size; i++){
    printf("%c\n", ((uint8_t*)s->avctx->extradata)[i]);
}
#endif

    *picture= *(AVFrame*)&a->picture;
    *data_size = sizeof(AVPicture);

    emms_c();

    return (get_bits_count(&a->gb)+31)/32*4;
}

#ifdef CONFIG_ENCODERS
static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
    ASV1Context * const a = avctx->priv_data;
    AVFrame *pict = data;
    AVFrame * const p= (AVFrame*)&a->picture;
    int size;
    int mb_x, mb_y;

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

    *p = *pict;
    p->pict_type= I_TYPE;
    p->key_frame= 1;

    for(mb_y=0; mb_y<a->mb_height2; mb_y++){
        for(mb_x=0; mb_x<a->mb_width2; mb_x++){
            dct_get(a, mb_x, mb_y);
            encode_mb(a, a->block);
        }
    }

    if(a->mb_width2 != a->mb_width){
        mb_x= a->mb_width2;
        for(mb_y=0; mb_y<a->mb_height2; mb_y++){
            dct_get(a, mb_x, mb_y);
            encode_mb(a, a->block);
        }
    }

    if(a->mb_height2 != a->mb_height){
        mb_y= a->mb_height2;
        for(mb_x=0; mb_x<a->mb_width; mb_x++){
            dct_get(a, mb_x, mb_y);
            encode_mb(a, a->block);
        }
    }
    emms_c();

    align_put_bits(&a->pb);
    while(put_bits_count(&a->pb)&31)
        put_bits(&a->pb, 8, 0);

    size= put_bits_count(&a->pb)/32;

    if(avctx->codec_id == CODEC_ID_ASV1)
        a->dsp.bswap_buf((uint32_t*)buf, (uint32_t*)buf, size);
    else{
        int i;
        for(i=0; i<4*size; i++)
            buf[i]= ff_reverse[ buf[i] ];
    }

    return size*4;
}
#endif /* CONFIG_ENCODERS */

static void common_init(AVCodecContext *avctx){
    ASV1Context * const a = avctx->priv_data;

    dsputil_init(&a->dsp, avctx);

    a->mb_width   = (avctx->width  + 15) / 16;
    a->mb_height  = (avctx->height + 15) / 16;
    a->mb_width2  = (avctx->width  + 0) / 16;
    a->mb_height2 = (avctx->height + 0) / 16;

    avctx->coded_frame= (AVFrame*)&a->picture;
    a->avctx= avctx;
}

static int decode_init(AVCodecContext *avctx){
    ASV1Context * const a = avctx->priv_data;
    AVFrame *p= (AVFrame*)&a->picture;
    int i;
    const int scale= avctx->codec_id == CODEC_ID_ASV1 ? 1 : 2;

    common_init(avctx);
    init_vlcs(a);
    ff_init_scantable(a->dsp.idct_permutation, &a->scantable, scantab);
    avctx->pix_fmt= PIX_FMT_YUV420P;

    a->inv_qscale= ((uint8_t*)avctx->extradata)[0];
    if(a->inv_qscale == 0){
        av_log(avctx, AV_LOG_ERROR, "illegal qscale 0\n");
        if(avctx->codec_id == CODEC_ID_ASV1)
            a->inv_qscale= 6;
        else
            a->inv_qscale= 10;
    }

    for(i=0; i<64; i++){
        int index= scantab[i];

        a->intra_matrix[i]= 64*scale*ff_mpeg1_default_intra_matrix[index] / a->inv_qscale;
    }

    p->qstride= a->mb_width;
    p->qscale_table= av_malloc( p->qstride * a->mb_height);
    p->quality= (32*scale + a->inv_qscale/2)/a->inv_qscale;
    memset(p->qscale_table, p->quality, p->qstride*a->mb_height);

    return 0;
}

#ifdef CONFIG_ENCODERS
static int encode_init(AVCodecContext *avctx){
    ASV1Context * const a = avctx->priv_data;
    int i;
    const int scale= avctx->codec_id == CODEC_ID_ASV1 ? 1 : 2;

    common_init(avctx);

    if(avctx->global_quality == 0) avctx->global_quality= 4*FF_QUALITY_SCALE;

    a->inv_qscale= (32*scale*FF_QUALITY_SCALE +  avctx->global_quality/2) / avctx->global_quality;

    avctx->extradata= av_mallocz(8);
    avctx->extradata_size=8;
    ((uint32_t*)avctx->extradata)[0]= le2me_32(a->inv_qscale);
    ((uint32_t*)avctx->extradata)[1]= le2me_32(ff_get_fourcc("ASUS"));

    for(i=0; i<64; i++){
        int q= 32*scale*ff_mpeg1_default_intra_matrix[i];
        a->q_intra_matrix[i]= ((a->inv_qscale<<16) + q/2) / q;
    }

    return 0;
}
#endif

static int decode_end(AVCodecContext *avctx){
    ASV1Context * const a = avctx->priv_data;

    av_freep(&a->bitstream_buffer);
    av_freep(&a->picture.qscale_table);
    a->bitstream_buffer_size=0;

    return 0;
}

AVCodec asv1_decoder = {
    "asv1",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ASV1,
    sizeof(ASV1Context),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
};

AVCodec asv2_decoder = {
    "asv2",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ASV2,
    sizeof(ASV1Context),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
};

#ifdef CONFIG_ENCODERS

AVCodec asv1_encoder = {
    "asv1",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ASV1,
    sizeof(ASV1Context),
    encode_init,
    encode_frame,
    //encode_end,
    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1},
};

AVCodec asv2_encoder = {
    "asv2",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ASV2,
    sizeof(ASV1Context),
    encode_init,
    encode_frame,
    //encode_end,
    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUV420P, -1},
};

#endif //CONFIG_ENCODERS