I am using Hitfilm 4 Express to create instructional videos for surgeons in training. I am editing video that is exported from the camera on a da Vinci robot (1920x1080, 29.97 fps, Codec: AVC/H.264, Audio: AAC although the mic was off, so no audio, Container: MPEG-4, duration 00:11:16, size 1GB). I have several different files that are made from the exact same machine, are the same codec/container, are the same size, and roughly the same length. 75% of them import just fine with no issue. The other 25%, when I import them I get the "thinking" wheel animation for several seconds and then the icon of the page with the "! triangle". No error box or anything, but the video has no length and no frames. Any assistance would be much appreciated. Thank you.