void *digitizer()
{
  char* dig_image;
  int tail = 0;

  while(1) {
    dig_image = read();

    pthread_mutex_lock(&buflock);
    if (bufavail == 0) {
      pthread_cond_wait(&buf_notempty, &buflock);
    }
    pthread_mutex_unlock(&buflock);

    frame_buf[tail%MAX] = dig_image;
    tail = tail + 1;

    pthread_mutex_lock(&buflock);
    bufavail = bufavail - 1;
    pthread_mutex_unlock(&buflock);

    if(bufavail < MAX) {
      pthread_cond_broadcast(&buf_notfull);
    }
  }
}

void *tracker()
{
  char *pSource;
  char *pDestination;
  char* track_image;
  int head = 0;

  while(1) {
    pthread_mutex_lock(&buflock);
    if (bufavail == MAX)
        pthread_cond_wait(&buf_notfull, &buflock);
    pthread_mutex_unlock(&buflock);

    pSource = frame_buf[head%MAX];
    head = head + 1;

    pthread_mutex_lock(&buflock);
    bufavail = bufavail + 1;
    pthread_mutex_unlock(&buflock);

    if(bufavail > 0) {
      pthread_cond_broadcast(&buf_notempty);
    }

    pDestination = (char *)malloc(HEIGHT * WIDTH);
    rotate(pSource, pDestination, HEIGHT, WIDTH);
  }
}