truemotion2.c

ffmpeg源码分析

    int i;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* low-res chroma */
    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* hi-res luma */
    for(i = 0; i < 16; i++)
        deltas[i] = GET_TOK(ctx, TM2_L_HI);

    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_low_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int t1, t2;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* low-res chroma */
    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* low-res luma */
    for(i = 0; i < 16; i++)
        deltas[i] = 0;

    deltas[ 0] = GET_TOK(ctx, TM2_L_LO);
    deltas[ 2] = GET_TOK(ctx, TM2_L_LO);
    deltas[ 8] = GET_TOK(ctx, TM2_L_LO);
    deltas[10] = GET_TOK(ctx, TM2_L_LO);

    if(bx > 0)
        last[0] = (last[-1] - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3] + last[1]) >> 1;
    else
        last[0] = (last[1]  - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3])>> 1;
    last[2] = (last[1] + last[3]) >> 1;

    t1 = ctx->D[0] + ctx->D[1];
    ctx->D[0] = t1 >> 1;
    ctx->D[1] = t1 - (t1 >> 1);
    t2 = ctx->D[2] + ctx->D[3];
    ctx->D[2] = t2 >> 1;
    ctx->D[3] = t2 - (t2 >> 1);

    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_null_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int ct;
    int left, right, diff;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* null chroma */
    deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* null luma */
    for(i = 0; i < 16; i++)
        deltas[i] = 0;

    ct = ctx->D[0] + ctx->D[1] + ctx->D[2] + ctx->D[3];

    if(bx > 0)
        left = last[-1] - ct;
    else
        left = 0;

    right = last[3];
    diff = right - left;
    last[0] = left + (diff >> 2);
    last[1] = left + (diff >> 1);
    last[2] = right - (diff >> 2);
    last[3] = right;
    {
        int tp = left;

        ctx->D[0] = (tp + (ct >> 2)) - left;
        left += ctx->D[0];
        ctx->D[1] = (tp + (ct >> 1)) - left;
        left += ctx->D[1];
        ctx->D[2] = ((tp + ct) - (ct >> 2)) - left;
        left += ctx->D[2];
        ctx->D[3] = (tp + ct) - left;
    }
    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_still_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    TM2_INIT_POINTERS_2();

    /* update chroma */
    for(j = 0; j < 2; j++){
        for(i = 0; i < 2; i++){
            U[i] = Uo[i];
            V[i] = Vo[i];
        }
        U += Ustride; V += Vstride;
        Uo += oUstride; Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* update deltas */
    ctx->D[0] = Yo[3] - last[3];
    ctx->D[1] = Yo[3 + oYstride] - Yo[3];
    ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
    ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];

    for(j = 0; j < 4; j++){
        for(i = 0; i < 4; i++){
            Y[i] = Yo[i];
            last[i] = Yo[i];
        }
        Y += Ystride;
        Yo += oYstride;
    }
}

static inline void tm2_update_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    int d;
    TM2_INIT_POINTERS_2();

    /* update chroma */
    for(j = 0; j < 2; j++){
        for(i = 0; i < 2; i++){
            U[i] = Uo[i] + GET_TOK(ctx, TM2_UPD);
            V[i] = Vo[i] + GET_TOK(ctx, TM2_UPD);
        }
        U += Ustride; V += Vstride;
        Uo += oUstride; Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* update deltas */
    ctx->D[0] = Yo[3] - last[3];
    ctx->D[1] = Yo[3 + oYstride] - Yo[3];
    ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
    ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];

    for(j = 0; j < 4; j++){
        d = last[3];
        for(i = 0; i < 4; i++){
            Y[i] = Yo[i] + GET_TOK(ctx, TM2_UPD);
            last[i] = Y[i];
        }
        ctx->D[j] = last[3] - d;
        Y += Ystride;
        Yo += oYstride;
    }
}

static inline void tm2_motion_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    int mx, my;
    TM2_INIT_POINTERS_2();

    mx = GET_TOK(ctx, TM2_MOT);
    my = GET_TOK(ctx, TM2_MOT);

    Yo += my * oYstride + mx;
    Uo += (my >> 1) * oUstride + (mx >> 1);
    Vo += (my >> 1) * oVstride + (mx >> 1);

    /* copy chroma */
    for(j = 0; j < 2; j++){
        for(i = 0; i < 2; i++){
            U[i] = Uo[i];
            V[i] = Vo[i];
        }
        U += Ustride; V += Vstride;
        Uo += oUstride; Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* copy luma */
    for(j = 0; j < 4; j++){
        for(i = 0; i < 4; i++){
            Y[i] = Yo[i];
        }
        Y += Ystride;
        Yo += oYstride;
    }
    /* calculate deltas */
    Y -= Ystride * 4;
    ctx->D[0] = Y[3] - last[3];
    ctx->D[1] = Y[3 + Ystride] - Y[3];
    ctx->D[2] = Y[3 + Ystride * 2] - Y[3 + Ystride];
    ctx->D[3] = Y[3 + Ystride * 3] - Y[3 + Ystride * 2];
    for(i = 0; i < 4; i++)
        last[i] = Y[i + Ystride * 3];
}

static int tm2_decode_blocks(TM2Context *ctx, AVFrame *p)
{
    int i, j;
    int bw, bh;
    int type;
    int keyframe = 1;
    uint8_t *Y, *U, *V;
    int *src;

    bw = ctx->avctx->width >> 2;
    bh = ctx->avctx->height >> 2;

    for(i = 0; i < TM2_NUM_STREAMS; i++)
        ctx->tok_ptrs[i] = 0;

    if (ctx->tok_lens[TM2_TYPE]<bw*bh){
        av_log(ctx->avctx,AV_LOG_ERROR,"Got %i tokens for %i blocks\n",ctx->tok_lens[TM2_TYPE],bw*bh);
        return -1;
    }

    memset(ctx->last, 0, 4 * bw * sizeof(int));
    memset(ctx->clast, 0, 4 * bw * sizeof(int));

    for(j = 0; j < bh; j++) {
        memset(ctx->D, 0, 4 * sizeof(int));
        memset(ctx->CD, 0, 4 * sizeof(int));
        for(i = 0; i < bw; i++) {
            type = GET_TOK(ctx, TM2_TYPE);
            switch(type) {
            case TM2_HI_RES:
                tm2_hi_res_block(ctx, p, i, j);
                break;
            case TM2_MED_RES:
                tm2_med_res_block(ctx, p, i, j);
                break;
            case TM2_LOW_RES:
                tm2_low_res_block(ctx, p, i, j);
                break;
            case TM2_NULL_RES:
                tm2_null_res_block(ctx, p, i, j);
                break;
            case TM2_UPDATE:
                tm2_update_block(ctx, p, i, j);
                keyframe = 0;
                break;
            case TM2_STILL:
                tm2_still_block(ctx, p, i, j);
                keyframe = 0;
                break;
            case TM2_MOTION:
                tm2_motion_block(ctx, p, i, j);
                keyframe = 0;
                break;
            default:
                av_log(ctx->avctx, AV_LOG_ERROR, "Skipping unknown block type %i\n", type);
            }
        }
    }

    /* copy data from our buffer to AVFrame */
    Y = p->data[0];
    src = (ctx->cur?ctx->Y2:ctx->Y1);
    for(j = 0; j < ctx->avctx->height; j++){
        for(i = 0; i < ctx->avctx->width; i++){
            Y[i] = clip_uint8(*src++);
        }
        Y += p->linesize[0];
    }
    U = p->data[2];
    src = (ctx->cur?ctx->U2:ctx->U1);
    for(j = 0; j < (ctx->avctx->height + 1) >> 1; j++){
        for(i = 0; i < (ctx->avctx->width + 1) >> 1; i++){
            U[i] = clip_uint8(*src++);
        }
        U += p->linesize[2];
    }
    V = p->data[1];
    src = (ctx->cur?ctx->V2:ctx->V1);
    for(j = 0; j < (ctx->avctx->height + 1) >> 1; j++){
        for(i = 0; i < (ctx->avctx->width + 1) >> 1; i++){
            V[i] = clip_uint8(*src++);
        }
        V += p->linesize[1];
    }

    return keyframe;
}

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *data_size,
                        uint8_t *buf, int buf_size)
{
    TM2Context * const l = avctx->priv_data;
    AVFrame * const p= (AVFrame*)&l->pic;
    int skip, t;

    p->reference = 1;
    p->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    if(avctx->reget_buffer(avctx, p) < 0){
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    l->dsp.bswap_buf((uint32_t*)buf, (uint32_t*)buf, buf_size >> 2);
    skip = tm2_read_header(l, buf);

    if(skip == -1)
        return -1;

    t = tm2_read_stream(l, buf + skip, TM2_C_HI);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_C_LO);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_L_HI);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_L_LO);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_UPD);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_MOT);
    if(t == -1)
        return -1;
    skip += t;
    t = tm2_read_stream(l, buf + skip, TM2_TYPE);
    if(t == -1)
        return -1;
    p->key_frame = tm2_decode_blocks(l, p);
    if(p->key_frame)
        p->pict_type = FF_I_TYPE;
    else
        p->pict_type = FF_P_TYPE;

    l->cur = !l->cur;
    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = l->pic;

    return buf_size;
}

static int decode_init(AVCodecContext *avctx){
    TM2Context * const l = avctx->priv_data;
    int i;

    if (avcodec_check_dimensions(avctx, avctx->height, avctx->width) < 0) {
        return -1;
    }
    if((avctx->width & 3) || (avctx->height & 3)){
        av_log(avctx, AV_LOG_ERROR, "Width and height must be multiple of 4\n");
        return -1;
    }

    l->avctx = avctx;
    l->pic.data[0]=NULL;
    avctx->has_b_frames = 0;
    avctx->pix_fmt = PIX_FMT_YUV420P;

    dsputil_init(&l->dsp, avctx);

    l->last = av_malloc(4 * sizeof(int) * (avctx->width >> 2));
    l->clast = av_malloc(4 * sizeof(int) * (avctx->width >> 2));

    for(i = 0; i < TM2_NUM_STREAMS; i++) {
        l->tokens[i] = NULL;
        l->tok_lens[i] = 0;
    }

    l->Y1 = av_malloc(sizeof(int) * avctx->width * avctx->height);
    l->U1 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
    l->V1 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
    l->Y2 = av_malloc(sizeof(int) * avctx->width * avctx->height);
    l->U2 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
    l->V2 = av_malloc(sizeof(int) * ((avctx->width + 1) >> 1) * ((avctx->height + 1) >> 1));
    l->cur = 0;

    return 0;
}

static int decode_end(AVCodecContext *avctx){
    TM2Context * const l = avctx->priv_data;
    int i;

    if(l->last)
        av_free(l->last);
    if(l->clast)
        av_free(l->clast);
    for(i = 0; i < TM2_NUM_STREAMS; i++)
        if(l->tokens[i])
            av_free(l->tokens[i]);
    if(l->Y1){
        av_free(l->Y1);
        av_free(l->U1);
        av_free(l->V1);
        av_free(l->Y2);
        av_free(l->U2);
        av_free(l->V2);
    }
    return 0;
}

AVCodec truemotion2_decoder = {
    "truemotion2",
    CODEC_TYPE_VIDEO,
    CODEC_ID_TRUEMOTION2,
    sizeof(TM2Context),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
};