!include once #1025007 // JCodec

static int framesFromVideo_bufferSize = 7;
static bool framesFromVideo_verbose;

static IterableIterator<BufferedImage> framesFromVideo_reordering(File video) ctex {
  final int bufferSize = framesFromVideo_bufferSize;
  final bool verbose = framesFromVideo_verbose;
  final FileChannelWrapper ch = NIOUtils.readableChannel(video);
  final AWTFrameGrab8Bit grab = AWTFrameGrab8Bit.createAWTFrameGrab8Bit(ch);
  
  ret iteratorFromFunction(new O {
    new TreeMap<Double, BufferedImage> reorderBuffer;
    bool done;
    
    void grab ctex {
      if (verbose) print("Grabbing (" + l(reorderBuffer) + ")");
      PictureWithMetadata8Bit pmd = grab.getNativeFrameWithMetadata();
      if (pmd == null) {
        done = true;
        NIOUtils.closeQuietly(ch);
      } else {
        BufferedImage img = AWTUtil.toBufferedImage8Bit(pmd.getPicture());
        reorderBuffer.put(pmd.getTimestamp(), img);
      }
    }
  
    O get() {
      while (!done && l(reorderBuffer) < bufferSize)
        grab();
        
      if (done || reorderBuffer.size() >= bufferSize) {
        if (empty(reorderBuffer)) null;
        double leastPts = firstKey(reorderBuffer);
        BufferedImage img = reorderBuffer.get(leastPts);
        reorderBuffer.remove(leastPts);
        if (verbose) print("Giving (" + l(reorderBuffer) + ")");
        ret img;
      }
      null;
    }
  });
  // TODO: close file when not all frames are grabbed
}

Began life as a copy of #1006727