When authoring a multi-angle or mixed-angle HD DVD project in DVD Studio Pro 4, the video streams in the track are limited to a combined maximum bit rate of 24 Mbps (this includes the selected video stream plus all audio and subtitle streams). 1080i HDV video uses a bit rate of 25 Mbps, which is higher than the maximum allowable multi-angle bit rate in the HD DVD specification.
It is possible to create a multi-angle project with HDV video if you use 720p HDV video, which uses a bit rate of 19 Mbps, depending on the number and type of audio and subtitle streams you use.