The violet line is from the authoring. The first few frames of the vob contains some frames of the DVD menu at the beginning, which messes the whole image up. I fixed it by cropping the image before resizing.

I applied QTGMC and MSharpen again and yes, it gets better results. The stars are brighter and there are more details. It blurs the picture a tiny bit, but it's a good trade-off. It looks really great now.