C++ VP56Context::parse_header方法代码示例

int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    VP56Context *s = avctx->priv_data;
    AVFrame *const p = s->frames[VP56_FRAME_CURRENT];
    int remaining_buf_size = avpkt->size;
    int av_uninit(alpha_offset);
    int i, res;
    int ret;

    if (s->has_alpha) {
        if (remaining_buf_size < 3)
            return -1;
        alpha_offset = bytestream_get_be24(&buf);
        remaining_buf_size -= 3;
        if (remaining_buf_size < alpha_offset)
            return -1;
    }

    res = s->parse_header(s, buf, remaining_buf_size);
    if (res < 0)
        return res;

    if (res == VP56_SIZE_CHANGE) {
        for (i = 0; i < 4; i++) {
            av_frame_unref(s->frames[i]);
            if (s->alpha_context)
                av_frame_unref(s->alpha_context->frames[i]);
        }
    }

    if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 0)
        return -1;

    if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) {
        av_frame_unref(s->alpha_context->frames[VP56_FRAME_CURRENT]);
        if ((ret = av_frame_ref(s->alpha_context->frames[VP56_FRAME_CURRENT], p)) < 0) {
            av_frame_unref(p);
            return ret;
        }
    }

    if (res == VP56_SIZE_CHANGE) {
        if (vp56_size_changed(s)) {
            av_frame_unref(p);
            return -1;
        }
    }

    if (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) {
        int bak_w = avctx->width;
        int bak_h = avctx->height;
        int bak_cw = avctx->coded_width;
        int bak_ch = avctx->coded_height;
        buf += alpha_offset;
        remaining_buf_size -= alpha_offset;

        res = s->alpha_context->parse_header(s->alpha_context, buf, remaining_buf_size);
        if (res != 0) {
            if(res==VP56_SIZE_CHANGE) {
                av_log(avctx, AV_LOG_ERROR, "Alpha reconfiguration\n");
                avctx->width  = bak_w;
                avctx->height = bak_h;
                avctx->coded_width  = bak_cw;
                avctx->coded_height = bak_ch;
            }
            av_frame_unref(p);
            return -1;
        }
    }

    avctx->execute2(avctx, ff_vp56_decode_mbs, 0, 0, (avctx->pix_fmt == AV_PIX_FMT_YUVA420P) + 1);

    if ((res = av_frame_ref(data, p)) < 0)
        return res;
    *got_frame = 1;

    return avpkt->size;
}

int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
                         AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    VP56Context *s = avctx->priv_data;
    AVFrame *const p = s->framep[VP56_FRAME_CURRENT];
    int remaining_buf_size = avpkt->size;
    int is_alpha, av_uninit(alpha_offset);

    if (s->has_alpha) {
        if (remaining_buf_size < 3)
            return -1;
        alpha_offset = bytestream_get_be24(&buf);
        remaining_buf_size -= 3;
        if (remaining_buf_size < alpha_offset)
            return -1;
    }

    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, remaining_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 = AV_PICTURE_TYPE_I;
            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 = AV_PICTURE_TYPE_P;
            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 = VP56_FRAME_NONE;
            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 = VP56_FRAME_CURRENT;
        s->above_blocks[3*s->mb_width + 4].ref_frame = VP56_FRAME_CURRENT;

        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 = VP56_FRAME_NONE;
                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;
//.........这里部分代码省略.........

int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    VP56Context *s = avctx->priv_data;
    AVFrame *p = 0;
    int remaining_buf_size = avpkt->size;
    int av_uninit(alpha_offset);
    int i, res;

    /* select a current frame from the unused frames */
    for (i = 0; i < 4; ++i) {
        if (!s->frames[i].data[0]) {
            p = &s->frames[i];
            break;
        }
    }
    av_assert0(p != 0);
    s->framep[VP56_FRAME_CURRENT] = p;
    if (s->alpha_context)
        s->alpha_context->framep[VP56_FRAME_CURRENT] = p;

    if (s->has_alpha) {
        if (remaining_buf_size < 3)
            return -1;
        alpha_offset = bytestream_get_be24(&buf);
        remaining_buf_size -= 3;
        if (remaining_buf_size < alpha_offset)
            return -1;
    }

    res = s->parse_header(s, buf, remaining_buf_size);
    if (res < 0)
        return res;

    if (res == VP56_SIZE_CHANGE) {
        for (i = 0; i < 4; i++) {
            if (s->frames[i].data[0])
                avctx->release_buffer(avctx, &s->frames[i]);
        }
    }

    p->reference = 3;
    if (ff_get_buffer(avctx, p) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    if (res == VP56_SIZE_CHANGE) {
        if (vp56_size_changed(s)) {
            avctx->release_buffer(avctx, p);
            return -1;
        }
    }

    if (s->has_alpha) {
        int bak_w = avctx->width;
        int bak_h = avctx->height;
        int bak_cw = avctx->coded_width;
        int bak_ch = avctx->coded_height;
        buf += alpha_offset;
        remaining_buf_size -= alpha_offset;

        res = s->alpha_context->parse_header(s->alpha_context, buf, remaining_buf_size);
        if (res != 0) {
            if(res==VP56_SIZE_CHANGE) {
                av_log(avctx, AV_LOG_ERROR, "Alpha reconfiguration\n");
                avctx->width  = bak_w;
                avctx->height = bak_h;
                avctx->coded_width  = bak_cw;
                avctx->coded_height = bak_ch;
            }
            avctx->release_buffer(avctx, p);
            return -1;
        }
    }

    avctx->execute2(avctx, ff_vp56_decode_mbs, 0, 0, s->has_alpha + 1);

    /* release frames that aren't in use */
    for (i = 0; i < 4; ++i) {
        AVFrame *victim = &s->frames[i];
        if (!victim->data[0])
            continue;
        if (victim != s->framep[VP56_FRAME_PREVIOUS] &&
            victim != s->framep[VP56_FRAME_GOLDEN] &&
            (!s->has_alpha || victim != s->alpha_context->framep[VP56_FRAME_GOLDEN]))
            avctx->release_buffer(avctx, victim);
    }

    p->qstride = 0;
    p->qscale_table = s->qscale_table;
    p->qscale_type = FF_QSCALE_TYPE_VP56;
    *(AVFrame*)data = *p;
    *got_frame = 1;

    return avpkt->size;
}