int update_dimensions(VP8Context *s, int width, int height, int is_vp7)
{
    AVCodecContext *avctx = s->avctx;
    int i, ret;

    if (width  != s->avctx->width || ((width+15)/16 != s->mb_width || (height+15)/16 != s->mb_height) && s->macroblocks_base ||
        height != s->avctx->height) {
        vp8_decode_flush_impl(s->avctx, 1);

        ret = ff_set_dimensions(s->avctx, width, height);
        if (ret < 0)
            return ret;
    }

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

    s->mb_layout = is_vp7 || avctx->active_thread_type == FF_THREAD_SLICE &&
                   avctx->thread_count > 1;
    if (!s->mb_layout) { // Frame threading and one thread
        s->macroblocks_base       = av_mallocz((s->mb_width + s->mb_height * 2 + 1) *
                                               sizeof(*s->macroblocks));
        s->intra4x4_pred_mode_top = av_mallocz(s->mb_width * 4);
    } else // Sliced threading
        s->macroblocks_base = av_mallocz((s->mb_width + 2) * (s->mb_height + 2) *
                                         sizeof(*s->macroblocks));
    s->top_nnz     = av_mallocz(s->mb_width * sizeof(*s->top_nnz));
    s->top_border  = av_mallocz((s->mb_width + 1) * sizeof(*s->top_border));
    s->thread_data = av_mallocz(MAX_THREADS * sizeof(VP8ThreadData));

    if (!s->macroblocks_base || !s->top_nnz || !s->top_border ||
        !s->thread_data || (!s->intra4x4_pred_mode_top && !s->mb_layout)) {
        free_buffers(s);
        return AVERROR(ENOMEM);
    }

    for (i = 0; i < MAX_THREADS; i++) {
        s->thread_data[i].filter_strength =
            av_mallocz(s->mb_width * sizeof(*s->thread_data[0].filter_strength));
        if (!s->thread_data[i].filter_strength) {
            free_buffers(s);
            return AVERROR(ENOMEM);
        }
#if HAVE_THREADS
        pthread_mutex_init(&s->thread_data[i].lock, NULL);
        pthread_cond_init(&s->thread_data[i].cond, NULL);
#endif
    }

    s->macroblocks = s->macroblocks_base + 1;

    return 0;
}
int update_dimensions(VP8Context *s, int width, int height, int is_vp7)
{
    AVCodecContext *avctx = s->avctx;
    int i, ret;

    if (width  != s->avctx->width || ((width+15)/16 != s->mb_width || (height+15)/16 != s->mb_height) && s->macroblocks_base ||
        height != s->avctx->height) {
        vp8_decode_flush_impl(s->avctx, 1);

        ret = ff_set_dimensions(s->avctx, width, height);
        if (ret < 0)
            return ret;
    }

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

    s->mb_layout = is_vp7 || avctx->active_thread_type == FF_THREAD_SLICE &&
                   avctx->thread_count > 1;
    if (!s->mb_layout) {  
        s->macroblocks_base       = av_mallocz((s->mb_width + s->mb_height * 2 + 1) *
                                               sizeof(*s->macroblocks));
        s->intra4x4_pred_mode_top = av_mallocz(s->mb_width * 4);
    } else  
        s->macroblocks_base = av_mallocz((s->mb_width + 2) * (s->mb_height + 2) *
                                         sizeof(*s->macroblocks));
    s->top_nnz     = av_mallocz(s->mb_width * sizeof(*s->top_nnz));
    s->top_border  = av_mallocz((s->mb_width + 1) * sizeof(*s->top_border));
    s->thread_data = av_mallocz(MAX_THREADS * sizeof(VP8ThreadData));

    if (!s->macroblocks_base || !s->top_nnz || !s->top_border ||
        !s->thread_data || (!s->intra4x4_pred_mode_top && !s->mb_layout)) {
        free_buffers(s);
        return AVERROR(ENOMEM);
    }

    for (i = 0; i < MAX_THREADS; i++) {
        s->thread_data[i].filter_strength =
            av_mallocz(s->mb_width * sizeof(*s->thread_data[0].filter_strength));
        if (!s->thread_data[i].filter_strength) {
            free_buffers(s);
            return AVERROR(ENOMEM);
        }
#if HAVE_THREADS
        pthread_mutex_init(&s->thread_data[i].lock, NULL);
        pthread_cond_init(&s->thread_data[i].cond, NULL);
#endif
    }

    s->macroblocks = s->macroblocks_base + 1;

    return 0;
}