static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
    AVStream *st;
    MOVStreamContext *sc;
    int ret;

    st = avformat_new_stream(c->fc, NULL);
    if (!st) return AVERROR(ENOMEM);
    st->id = c->fc->nb_streams;
    sc = av_mallocz(sizeof(MOVStreamContext));
    if (!sc) return AVERROR(ENOMEM);

    st->priv_data = sc;
    st->codec->codec_type = AVMEDIA_TYPE_DATA;
    sc->ffindex = st->index;

    if ((ret = mov_read_default(c, pb, atom)) < 0)
        return ret;

    /* sanity checks */
    if (sc->chunk_count && (!sc->stts_count || !sc->stsc_count ||
                            (!sc->sample_size && !sc->sample_count))) {
        av_log(c->fc, AV_LOG_ERROR, "stream %d, missing mandatory atoms, broken header\n",
               st->index);
        return 0;
    }

    if (sc->time_scale <= 0) {
        av_log(c->fc, AV_LOG_WARNING, "stream %d, timescale not set\n", st->index);
        sc->time_scale = c->time_scale;
        if (sc->time_scale <= 0)
            sc->time_scale = 1;
    }

    avpriv_set_pts_info(st, 64, 1, sc->time_scale);

    mov_build_index(c, st);

    if (sc->dref_id-1 < sc->drefs_count && sc->drefs[sc->dref_id-1].path) {
        MOVDref *dref = &sc->drefs[sc->dref_id - 1];
        if (mov_open_dref(&sc->pb, c->fc->filename, dref, &c->fc->interrupt_callback,
            c->use_absolute_path, c->fc) < 0)
            av_log(c->fc, AV_LOG_ERROR,
                   "stream %d, error opening alias: path='%s', dir='%s', "
                   "filename='%s', volume='%s', nlvl_from=%d, nlvl_to=%d\n",
                   st->index, dref->path, dref->dir, dref->filename,
                   dref->volume, dref->nlvl_from, dref->nlvl_to);
    } else
        sc->pb = c->fc->pb;

    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
        if (!st->sample_aspect_ratio.num &&
            (st->codec->width != sc->width || st->codec->height != sc->height)) {
            st->sample_aspect_ratio = av_d2q(((double)st->codec->height * sc->width) /
                                             ((double)st->codec->width * sc->height), INT_MAX);
        }

        av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
                  sc->time_scale*st->nb_frames, st->duration, INT_MAX);

        if (sc->stts_count == 1 || (sc->stts_count == 2 && sc->stts_data[1].count == 1))
            av_reduce(&st->r_frame_rate.num, &st->r_frame_rate.den,
                      sc->time_scale, sc->stts_data[0].duration, INT_MAX);
    }

    switch (st->codec->codec_id) {
#if CONFIG_H261_DECODER
    case CODEC_ID_H261:
#endif
#if CONFIG_H263_DECODER
    case CODEC_ID_H263:
#endif
#if CONFIG_H264_DECODER
    case CODEC_ID_H264:
#endif
#if CONFIG_MPEG4_DECODER
    case CODEC_ID_MPEG4:
#endif
        st->codec->width = 0; /* let decoder init width/height */
        st->codec->height= 0;
        break;
    }

    /* Do not need those anymore. */
    av_freep(&sc->chunk_offsets);
    av_freep(&sc->stsc_data);
    av_freep(&sc->sample_sizes);
    av_freep(&sc->keyframes);
    av_freep(&sc->stts_data);
    av_freep(&sc->stps_data);

    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.