I found the weirdest thing in Vegas Pro 13. I was trying to verify the exact frames of a generated file, so was looking for a zero number frame to drop it into the timeline. I was surprised to find that two frames in the Vegas Pro timeline are missing. The timeline goes from
00:14:00;02. There should be a
;01 entry there as well, but it's not present. See in the image below, zoomed in so that each vertical line is a frame. The two frames missing are between the blue line.
My first thought was something to do with NTSC 29.97 framerate vs actual 30 framerate. I figured if that's the case, the issue should repeat at regular intervals. I checked between other values and determined that the issue repeats every minute, except at 10 minute marks (it may be more nuanced than that).
How can I make it not do this?
Why, you ask? I edit in Vegas Pro like any other vidiot, but then I use the events window to extract all the timeline data then render in ffmpeg. This means that If I try to target a specific frame, I may actually be off by several frames. This is an issue because some of my process is creating separate video and audio files, but they play simultaneously, so I can't tolerate more than 1 frame off for the lip sync.
My thought is that I need to record in true 30 fps, then everything will fall in line. Is that the only solution? How can I account for this in my ffmpeg scripts? For example, if I see
00:14:00;02 in Vegas Pro, do I need to tell ffmpeg that the actual frame to target is less than that? If I have a 10 hour clip, 2 frames difference every minute adds up to a lot of frames. Almost a minute! I haven't looked closely at any of my renders to see if I notice a subjective lip sync issue.