SpenceEdit said:

so the video stream from my mkv comes out as ".h264" format. I can't open that with anything. Anyone know what my next step should be? I figure it needs to be mp4/move, but it doesn't come out that way.

You might want to take this into the technical help forum to avoid taking your thread off-topic, but basically if you mux the extracted h264 raw stream into an .m2ts transport stream (with tsmuxer) or an .mp4 container (with YAMB), then Vegas should then be able to open it.