Neither is raw. The frames are drawn differently. The I frame means that all the information is in every frame. The B P frames are drawn with partial data that changed from the I frame. So say first frame is an I frame and the next 3 or 4 frames the only thing that changed was the subject moved then only the movement is drawn where the original background I frame is the same.
I use IPB with my Canon 5d mark iii and the quality is very good.