static int smka_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    AVFrame *frame     = data;
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    BitstreamContext bc;
    HuffContext h[4] = { { 0 } };
    VLC vlc[4]       = { { 0 } };
    int16_t *samples;
    uint8_t *samples8;
    int val;
    int i, res, ret;
    int unp_size;
    int bits, stereo;
    int pred[2] = {0, 0};

    if (buf_size <= 4) {
        av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
        return AVERROR_INVALIDDATA;
    }

    unp_size = AV_RL32(buf);

    bitstream_init8(&bc, buf + 4, buf_size - 4);

    if (!bitstream_read_bit(&bc)) {
        av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
        *got_frame_ptr = 0;
        return 1;
    }
    stereo = bitstream_read_bit(&bc);
    bits   = bitstream_read_bit(&bc);
    if (stereo ^ (avctx->channels != 1)) {
        av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
        return AVERROR_INVALIDDATA;
    }
    if (bits && avctx->sample_fmt == AV_SAMPLE_FMT_U8) {
        av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
        return AVERROR_INVALIDDATA;
    }
    if (unp_size % (avctx->channels * (bits + 1))) {
        av_log(avctx, AV_LOG_ERROR,
               "The buffer does not contain an integer number of samples\n");
        return AVERROR_INVALIDDATA;
    }

    /* get output buffer */
    frame->nb_samples = unp_size / (avctx->channels * (bits + 1));
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return ret;
    }
    samples  = (int16_t *)frame->data[0];
    samples8 =            frame->data[0];

    for(i = 0; i < (1 << (bits + stereo)); i++) {
        h[i].length = 256;
        h[i].maxlength = 0;
        h[i].current = 0;
        h[i].bits = av_mallocz(256 * 4);
        h[i].lengths = av_mallocz(256 * sizeof(int));
        h[i].values = av_mallocz(256 * sizeof(int));
        if (!h[i].bits || !h[i].lengths || !h[i].values) {
            ret = AVERROR(ENOMEM);
            goto error;
        }
        bitstream_skip(&bc, 1);
        if (smacker_decode_tree(&bc, &h[i], 0, 0) < 0) {
            ret = AVERROR_INVALIDDATA;
            goto error;
        }
        bitstream_skip(&bc, 1);
        if(h[i].current > 1) {
            res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
                    h[i].lengths, sizeof(int), sizeof(int),
                    h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
            if(res < 0) {
                av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
                ret = AVERROR_INVALIDDATA;
                goto error;
            }
        }
    }
    /* this codec relies on wraparound instead of clipping audio */
    if(bits) { //decode 16-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = sign_extend(av_bswap16(bitstream_read(&bc, 16)), 16);
        for(i = 0; i <= stereo; i++)
            *samples++ = pred[i];
        for(; i < unp_size / 2; i++) {
            if(i & stereo) {
                if(vlc[2].table)
                    res = bitstream_read_vlc(&bc, vlc[2].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[2].values[res];
                if(vlc[3].table)
                    res = bitstream_read_vlc(&bc, vlc[3].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[3].values[res] << 8;
                pred[1] += sign_extend(val, 16);
                *samples++ = pred[1];
            } else {
                if(vlc[0].table)
                    res = bitstream_read_vlc(&bc, vlc[0].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[0].values[res];
                if(vlc[1].table)
                    res = bitstream_read_vlc(&bc, vlc[1].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[1].values[res] << 8;
                pred[0] += sign_extend(val, 16);
                *samples++ = pred[0];
            }
        }
    } else { //8-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = bitstream_read(&bc, 8);
        for(i = 0; i <= stereo; i++)
            *samples8++ = pred[i];
        for(; i < unp_size; i++) {
            if(i & stereo){
                if(vlc[1].table)
                    res = bitstream_read_vlc(&bc, vlc[1].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                pred[1] += sign_extend(h[1].values[res], 8);
                *samples8++ = pred[1];
            } else {
                if(vlc[0].table)
                    res = bitstream_read_vlc(&bc, vlc[0].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                pred[0] += sign_extend(h[0].values[res], 8);
                *samples8++ = pred[0];
            }
        }
    }

    *got_frame_ptr = 1;
    ret = buf_size;

error:
    for(i = 0; i < 4; i++) {
        if(vlc[i].table)
            ff_free_vlc(&vlc[i]);
        av_free(h[i].bits);
        av_free(h[i].lengths);
        av_free(h[i].values);
    }

    return ret;
}

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.