static int update_frame_pool(AVCodecContext *avctx, AVFrame *frame)
{
    FramePool *pool = avctx->internal->pool;
    int i, ret;

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO: {
        AVPicture picture;
        int size[4] = { 0 };
        int w = frame->width;
        int h = frame->height;
        int tmpsize, unaligned;

        if (pool->format == frame->format &&
            pool->width == frame->width && pool->height == frame->height)
            return 0;

        avcodec_align_dimensions2(avctx, &w, &h, pool->stride_align);

        if (!(avctx->flags & CODEC_FLAG_EMU_EDGE)) {
            w += EDGE_WIDTH * 2;
            h += EDGE_WIDTH * 2;
        }

        do {
            // NOTE: do not align linesizes individually, this breaks e.g. assumptions
            // that linesize[0] == 2*linesize[1] in the MPEG-encoder for 4:2:2
            av_image_fill_linesizes(picture.linesize, avctx->pix_fmt, w);
            // increase alignment of w for next try (rhs gives the lowest bit set in w)
            w += w & ~(w - 1);

            unaligned = 0;
            for (i = 0; i < 4; i++)
                unaligned |= picture.linesize[i] % pool->stride_align[i];
        } while (unaligned);

        tmpsize = av_image_fill_pointers(picture.data, avctx->pix_fmt, h,
                                         NULL, picture.linesize);
        if (tmpsize < 0)
            return -1;

        for (i = 0; i < 3 && picture.data[i + 1]; i++)
            size[i] = picture.data[i + 1] - picture.data[i];
        size[i] = tmpsize - (picture.data[i] - picture.data[0]);

        for (i = 0; i < 4; i++) {
            av_buffer_pool_uninit(&pool->pools[i]);
            pool->linesize[i] = picture.linesize[i];
            if (size[i]) {
                pool->pools[i] = av_buffer_pool_init(size[i] + 16 + STRIDE_ALIGN - 1,
                                                     CONFIG_MEMORY_POISONING ?
                                                        NULL :
                                                        av_buffer_allocz);
                if (!pool->pools[i]) {
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
            }
        }
        pool->format = frame->format;
        pool->width  = frame->width;
        pool->height = frame->height;

        break;
        }
    case AVMEDIA_TYPE_AUDIO: {
        int ch     = av_frame_get_channels(frame); //av_get_channel_layout_nb_channels(frame->channel_layout);
        int planar = av_sample_fmt_is_planar(frame->format);
        int planes = planar ? ch : 1;

        if (pool->format == frame->format && pool->planes == planes &&
            pool->channels == ch && frame->nb_samples == pool->samples)
            return 0;

        av_buffer_pool_uninit(&pool->pools[0]);
        ret = av_samples_get_buffer_size(&pool->linesize[0], ch,
                                         frame->nb_samples, frame->format, 0);
        if (ret < 0)
            goto fail;

        pool->pools[0] = av_buffer_pool_init(pool->linesize[0], NULL);
        if (!pool->pools[0]) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

        pool->format     = frame->format;
        pool->planes     = planes;
        pool->channels   = ch;
        pool->samples = frame->nb_samples;
        break;
        }
    default: av_assert0(0);
    }
    return 0;
fail:
    for (i = 0; i < 4; i++)
        av_buffer_pool_uninit(&pool->pools[i]);
    pool->format = -1;
    pool->planes = pool->channels = pool->samples = 0;
    pool->width  = pool->height = 0;
    return ret;
}
Unknown