vp56.c

mediastreamer2是开源的网络传输媒体流的库

    if (x<0 || x+12>=s->plane_width[plane] ||
        y<0 || y+12>=s->plane_height[plane]) {
        ff_emulated_edge_mc(s->edge_emu_buffer,
                            src + s->block_offset[b] + (dy-2)*stride + (dx-2),
                            stride, 12, 12, x, y,
                            s->plane_width[plane],
                            s->plane_height[plane]);
        src_block = s->edge_emu_buffer;
        src_offset = 2 + 2*stride;
    } else if (deblock_filtering) {
        /* only need a 12x12 block, but there is no such dsp function, */
        /* so copy a 16x12 block */
        s->dsp.put_pixels_tab[0][0](s->edge_emu_buffer,
                                    src + s->block_offset[b] + (dy-2)*stride + (dx-2),
                                    stride, 12);
        src_block = s->edge_emu_buffer;
        src_offset = 2 + 2*stride;
    } else {
        src_block = src;
        src_offset = s->block_offset[b] + dy*stride + dx;
    }

    if (deblock_filtering)
        vp56_deblock_filter(s, src_block, stride, dx&7, dy&7);

    if (s->mv[b].x & mask)
        overlap_offset += (s->mv[b].x > 0) ? 1 : -1;
    if (s->mv[b].y & mask)
        overlap_offset += (s->mv[b].y > 0) ? stride : -stride;

    if (overlap_offset) {
        if (s->filter)
            s->filter(s, dst, src_block, src_offset, src_offset+overlap_offset,
                      stride, s->mv[b], mask, s->filter_selection, b<4);
        else
            s->dsp.put_no_rnd_pixels_l2[1](dst, src_block+src_offset,
                                           src_block+src_offset+overlap_offset,
                                           stride, 8);
    } else {
        s->dsp.put_pixels_tab[1][0](dst, src_block+src_offset, stride, 8);
    }
}

static void vp56_decode_mb(vp56_context_t *s, int row, int col, int is_alpha)
{
    AVFrame *frame_current, *frame_ref;
    vp56_mb_t mb_type;
    vp56_frame_t ref_frame;
    int b, ab, b_max, plane, off;

    if (s->framep[VP56_FRAME_CURRENT]->key_frame)
        mb_type = VP56_MB_INTRA;
    else
        mb_type = vp56_decode_mv(s, row, col);
    ref_frame = vp56_reference_frame[mb_type];

    memset(s->block_coeff, 0, sizeof(s->block_coeff));

    s->parse_coeff(s);

    vp56_add_predictors_dc(s, ref_frame);

    frame_current = s->framep[VP56_FRAME_CURRENT];
    frame_ref = s->framep[ref_frame];

    ab = 6*is_alpha;
    b_max = 6 - 2*is_alpha;

    switch (mb_type) {
        case VP56_MB_INTRA:
            for (b=0; b<b_max; b++) {
                plane = vp56_b2p[b+ab];
                s->dsp.idct_put(frame_current->data[plane] + s->block_offset[b],
                                s->stride[plane], s->block_coeff[b]);
            }
            break;

        case VP56_MB_INTER_NOVEC_PF:
        case VP56_MB_INTER_NOVEC_GF:
            for (b=0; b<b_max; b++) {
                plane = vp56_b2p[b+ab];
                off = s->block_offset[b];
                s->dsp.put_pixels_tab[1][0](frame_current->data[plane] + off,
                                            frame_ref->data[plane] + off,
                                            s->stride[plane], 8);
                s->dsp.idct_add(frame_current->data[plane] + off,
                                s->stride[plane], s->block_coeff[b]);
            }
            break;

        case VP56_MB_INTER_DELTA_PF:
        case VP56_MB_INTER_V1_PF:
        case VP56_MB_INTER_V2_PF:
        case VP56_MB_INTER_DELTA_GF:
        case VP56_MB_INTER_4V:
        case VP56_MB_INTER_V1_GF:
        case VP56_MB_INTER_V2_GF:
            for (b=0; b<b_max; b++) {
                int x_off = b==1 || b==3 ? 8 : 0;
                int y_off = b==2 || b==3 ? 8 : 0;
                plane = vp56_b2p[b+ab];
                vp56_mc(s, b, plane, frame_ref->data[plane], s->stride[plane],
                        16*col+x_off, 16*row+y_off);
                s->dsp.idct_add(frame_current->data[plane] + s->block_offset[b],
                                s->stride[plane], s->block_coeff[b]);
            }
            break;
    }
}

static int vp56_size_changed(AVCodecContext *avctx)
{
    vp56_context_t *s = avctx->priv_data;
    int stride = s->framep[VP56_FRAME_CURRENT]->linesize[0];
    int i;

    s->plane_width[0]  = s->plane_width[3]  = avctx->coded_width;
    s->plane_width[1]  = s->plane_width[2]  = avctx->coded_width/2;
    s->plane_height[0] = s->plane_height[3] = avctx->coded_height;
    s->plane_height[1] = s->plane_height[2] = avctx->coded_height/2;

    for (i=0; i<4; i++)
        s->stride[i] = s->flip * s->framep[VP56_FRAME_CURRENT]->linesize[i];

    s->mb_width  = (avctx->coded_width +15) / 16;
    s->mb_height = (avctx->coded_height+15) / 16;

    if (s->mb_width > 1000 || s->mb_height > 1000) {
        av_log(avctx, AV_LOG_ERROR, "picture too big\n");
        return -1;
    }

    s->above_blocks = av_realloc(s->above_blocks,
                                 (4*s->mb_width+6) * sizeof(*s->above_blocks));
    s->macroblocks = av_realloc(s->macroblocks,
                                s->mb_width*s->mb_height*sizeof(*s->macroblocks));
    av_free(s->edge_emu_buffer_alloc);
    s->edge_emu_buffer_alloc = av_malloc(16*stride);
    s->edge_emu_buffer = s->edge_emu_buffer_alloc;
    if (s->flip < 0)
        s->edge_emu_buffer += 15 * stride;

    return 0;
}

int vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                      const uint8_t *buf, int buf_size)
{
    vp56_context_t *s = avctx->priv_data;
    AVFrame *const p = s->framep[VP56_FRAME_CURRENT];
    int is_alpha, alpha_offset;

    if (s->has_alpha) {
        alpha_offset = bytestream_get_be24(&buf);
        buf_size -= 3;
    }

    for (is_alpha=0; is_alpha < 1+s->has_alpha; is_alpha++) {
        int mb_row, mb_col, mb_row_flip, mb_offset = 0;
        int block, y, uv, stride_y, stride_uv;
        int golden_frame = 0;
        int res;

        s->modelp = &s->models[is_alpha];

        res = s->parse_header(s, buf, buf_size, &golden_frame);
        if (!res)
            return -1;

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

            if (res == 2)
                if (vp56_size_changed(avctx)) {
                    avctx->release_buffer(avctx, p);
                    return -1;
                }
        }

        if (p->key_frame) {
            p->pict_type = FF_I_TYPE;
            s->default_models_init(s);
            for (block=0; block<s->mb_height*s->mb_width; block++)
                s->macroblocks[block].type = VP56_MB_INTRA;
        } else {
            p->pict_type = FF_P_TYPE;
            vp56_parse_mb_type_models(s);
            s->parse_vector_models(s);
            s->mb_type = VP56_MB_INTER_NOVEC_PF;
        }

        s->parse_coeff_models(s);

        memset(s->prev_dc, 0, sizeof(s->prev_dc));
        s->prev_dc[1][VP56_FRAME_CURRENT] = 128;
        s->prev_dc[2][VP56_FRAME_CURRENT] = 128;

        for (block=0; block < 4*s->mb_width+6; block++) {
            s->above_blocks[block].ref_frame = -1;
            s->above_blocks[block].dc_coeff = 0;
            s->above_blocks[block].not_null_dc = 0;
        }
        s->above_blocks[2*s->mb_width + 2].ref_frame = 0;
        s->above_blocks[3*s->mb_width + 4].ref_frame = 0;

        stride_y  = p->linesize[0];
        stride_uv = p->linesize[1];

        if (s->flip < 0)
            mb_offset = 7;

        /* main macroblocks loop */
        for (mb_row=0; mb_row<s->mb_height; mb_row++) {
            if (s->flip < 0)
                mb_row_flip = s->mb_height - mb_row - 1;
            else
                mb_row_flip = mb_row;

            for (block=0; block<4; block++) {
                s->left_block[block].ref_frame = -1;
                s->left_block[block].dc_coeff = 0;
                s->left_block[block].not_null_dc = 0;
            }
            memset(s->coeff_ctx, 0, sizeof(s->coeff_ctx));
            memset(s->coeff_ctx_last, 24, sizeof(s->coeff_ctx_last));

            s->above_block_idx[0] = 1;
            s->above_block_idx[1] = 2;
            s->above_block_idx[2] = 1;
            s->above_block_idx[3] = 2;
            s->above_block_idx[4] = 2*s->mb_width + 2 + 1;
            s->above_block_idx[5] = 3*s->mb_width + 4 + 1;

            s->block_offset[s->frbi] = (mb_row_flip*16 + mb_offset) * stride_y;
            s->block_offset[s->srbi] = s->block_offset[s->frbi] + 8*stride_y;
            s->block_offset[1] = s->block_offset[0] + 8;
            s->block_offset[3] = s->block_offset[2] + 8;
            s->block_offset[4] = (mb_row_flip*8 + mb_offset) * stride_uv;
            s->block_offset[5] = s->block_offset[4];

            for (mb_col=0; mb_col<s->mb_width; mb_col++) {
                vp56_decode_mb(s, mb_row, mb_col, is_alpha);

                for (y=0; y<4; y++) {
                    s->above_block_idx[y] += 2;
                    s->block_offset[y] += 16;
                }

                for (uv=4; uv<6; uv++) {
                    s->above_block_idx[uv] += 1;
                    s->block_offset[uv] += 8;
                }
            }
        }

        if (p->key_frame || golden_frame) {
            if (s->framep[VP56_FRAME_GOLDEN]->data[0] &&
                s->framep[VP56_FRAME_GOLDEN] != s->framep[VP56_FRAME_GOLDEN2])
                avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN]);
            s->framep[VP56_FRAME_GOLDEN] = p;
        }

        if (s->has_alpha) {
            FFSWAP(AVFrame *, s->framep[VP56_FRAME_GOLDEN],
                              s->framep[VP56_FRAME_GOLDEN2]);
            buf += alpha_offset;
            buf_size -= alpha_offset;
        }
    }

    if (s->framep[VP56_FRAME_PREVIOUS] == s->framep[VP56_FRAME_GOLDEN] ||
        s->framep[VP56_FRAME_PREVIOUS] == s->framep[VP56_FRAME_GOLDEN2]) {
        if (s->framep[VP56_FRAME_UNUSED] != s->framep[VP56_FRAME_GOLDEN] &&
            s->framep[VP56_FRAME_UNUSED] != s->framep[VP56_FRAME_GOLDEN2])
            FFSWAP(AVFrame *, s->framep[VP56_FRAME_PREVIOUS],
                              s->framep[VP56_FRAME_UNUSED]);
        else
            FFSWAP(AVFrame *, s->framep[VP56_FRAME_PREVIOUS],
                              s->framep[VP56_FRAME_UNUSED2]);
    } else if (s->framep[VP56_FRAME_PREVIOUS]->data[0])
        avctx->release_buffer(avctx, s->framep[VP56_FRAME_PREVIOUS]);
    FFSWAP(AVFrame *, s->framep[VP56_FRAME_CURRENT],
                      s->framep[VP56_FRAME_PREVIOUS]);

    *(AVFrame*)data = *p;
    *data_size = sizeof(AVFrame);

    return buf_size;
}

void vp56_init(AVCodecContext *avctx, int flip, int has_alpha)
{
    vp56_context_t *s = avctx->priv_data;
    int i;

    s->avctx = avctx;
    avctx->pix_fmt = has_alpha ? PIX_FMT_YUVA420P : PIX_FMT_YUV420P;

    if (avctx->idct_algo == FF_IDCT_AUTO)
        avctx->idct_algo = FF_IDCT_VP3;
    dsputil_init(&s->dsp, avctx);
    ff_init_scantable(s->dsp.idct_permutation, &s->scantable,ff_zigzag_direct);

    avcodec_set_dimensions(avctx, 0, 0);

    for (i=0; i<4; i++)
        s->framep[i] = &s->frames[i];
    s->framep[VP56_FRAME_UNUSED] = s->framep[VP56_FRAME_GOLDEN];
    s->framep[VP56_FRAME_UNUSED2] = s->framep[VP56_FRAME_GOLDEN2];
    s->edge_emu_buffer_alloc = NULL;

    s->above_blocks = NULL;
    s->macroblocks = NULL;
    s->quantizer = -1;
    s->deblock_filtering = 1;

    s->filter = NULL;

    s->has_alpha = has_alpha;
    if (flip) {
        s->flip = -1;
        s->frbi = 2;
        s->srbi = 0;
    } else {
        s->flip = 1;
        s->frbi = 0;
        s->srbi = 2;
    }
}

int vp56_free(AVCodecContext *avctx)
{
    vp56_context_t *s = avctx->priv_data;

    av_free(s->above_blocks);
    av_free(s->macroblocks);
    av_free(s->edge_emu_buffer_alloc);
    if (s->framep[VP56_FRAME_GOLDEN]->data[0])
        avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN]);
    if (s->framep[VP56_FRAME_GOLDEN2]->data[0])
        avctx->release_buffer(avctx, s->framep[VP56_FRAME_GOLDEN2]);
    if (s->framep[VP56_FRAME_PREVIOUS]->data[0])
        avctx->release_buffer(avctx, s->framep[VP56_FRAME_PREVIOUS]);
    return 0;
}