The other day I filmed some shots on my iPhone and added them to my Vegas project. All of the videos were 60fps MOV files, but I renamed some of them to MP4 because I was under the impression that this was OK. All of the videos play fine in the preview window, but when the project is rendered the video is just a plain black screen. I can hear audio as well as see overlayed text and images just fine, but the videos themselves are black. I've disabled resample on all of the clips, and I've tried outputting to multiple different file formats. Does anyone know a fix for this problem?