Noise problem when transforming and quantizing difference between images
JPEG was developed for photographic content, not for difference-of-pictures content. Therefore, the fact that it's not overly applicable to the difference between successive frames isn't surprising.

In your specific quantization approach, where you eradicate high frequencies, that's actually even pretty intuitive: The difference between successive frames are probably small, and fine-grained. Of course, when you erase high frequency content, you lose most of the difference information and get a large error. So, I'd call this an indication that your high-frequency deletion works, and little more.

So, wrong approach to video coding; you could use JPEG for I-frames and code the differences to previous frames with some sort of linear predictor. Or, look at existing video codecs, and adapt some of the methods used there - in the case of grass, which presumably is blowing in the wind in a pretty uniform direction with smaller local variations, motion prediction coding might be of special interest to you.