static int vp7_fade_frame(VP8Context *s, VP56RangeCoder *c)
{
    int alpha = (int8_t) vp8_rac_get_uint(c, 8);
    int beta  = (int8_t) vp8_rac_get_uint(c, 8);
    int ret;

    if (!s->keyframe && (alpha || beta)) {
        int width  = s->mb_width * 16;
        int height = s->mb_height * 16;
        AVFrame *src, *dst;

        if (!s->framep[VP56_FRAME_PREVIOUS] ||
            !s->framep[VP56_FRAME_GOLDEN]) {
            av_log(s->avctx, AV_LOG_WARNING, "Discarding interframe without a prior keyframe!\n");
            return AVERROR_INVALIDDATA;
        }

        dst =
        src = s->framep[VP56_FRAME_PREVIOUS]->tf.f;

        /* preserve the golden frame, write a new previous frame */
        if (s->framep[VP56_FRAME_GOLDEN] == s->framep[VP56_FRAME_PREVIOUS]) {
            s->framep[VP56_FRAME_PREVIOUS] = vp8_find_free_buffer(s);
            if ((ret = vp8_alloc_frame(s, s->framep[VP56_FRAME_PREVIOUS], 1)) < 0)
                return ret;

            dst = s->framep[VP56_FRAME_PREVIOUS]->tf.f;

            copy_chroma(dst, src, width, height);
        }

        fade(dst->data[0], dst->linesize[0],
             src->data[0], src->linesize[0],
             width, height, alpha, beta);
    }

    return 0;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.