Project auto-adjust / 1080 30 fps -> NTSC 29.9

Frans Meijer wrote on 5/29/2014, 5:13 AM
So, I create a 30 fps 1080p project, put 30 fps 1080p (pc-captured) material on the time-line and VP13 asks if it should match project setting to the material, and when I accept, it changes the project to NTSC 29,9xx fps.

Why does it think the material is in 29.9 and not in 30 fps while it's recorded in 30 fps and everything else is telling me it is 30 fps? How will this affect editing, will Vegas start duplicating every 1000 frame to 'match' frame-rates?

In this age, why does it prefer the awkward 29.9 frame-rate anyway?

Comments

Former user wrote on 5/29/2014, 6:46 AM
What camera are you shooting with? Some cameras do shoot true 30fps, but this is non-standard for NTSC.
Frans Meijer wrote on 5/29/2014, 8:10 AM
I was playing around, using Open Broadcaster Software to capture desktop/monitor, set to 30 fps, 1080p. I have zero interest in 29.9xx, camera footage would likely be in 25p or 50i, which are more common where I live, internet distribution is 30p.

As an aside, why cling to NTSC framerates? There is no technical reason to do so, distribution is digital, display is digital, it is time to let the
Former user wrote on 5/29/2014, 8:12 AM
In the US we have to use NTSC framerates because that is the broadcast standard. Internet distribution can be whatever you want since, as you say, it is all digital.

You can avoid your problem by not letting the software change your project settings if it is indeed true 30 FPS..
musicvid10 wrote on 5/29/2014, 8:21 AM
Your footage is likely 29.97, often labeled as 30 fps.
What does MediaInfo say?
Frans Meijer wrote on 5/29/2014, 8:39 AM
Yeah, I realize that, I was just curious why it would change a 30 fps project to 29.97 when being given 30 fps material. It is after all suggesting to change project setttings to match the source material.

Mediainfo says it's 30.00 fps, variable with min 29.4 and max 30.3 fps

Frame rate mode : Variable
Frame rate : 30.000 fps
Minimum frame rate : 29.412 fps
Maximum frame rate : 30.303 fps
Frans Meijer wrote on 5/29/2014, 8:48 AM
It might be because of the variable framerate, when I create a 30 fps testvideo it doesn't change anything.
musicvid10 wrote on 5/29/2014, 9:38 AM
Vegas (at least older versions) do not report variable frame rate source correctly.

Since your software uses x264, it will always report variable frame rate, even if it is not (has to do with ref clock frequencies and rounding algorithms). This is unlikely to change.

Type the frame rate in manually in the Project Properties.
Frans Meijer wrote on 5/29/2014, 10:06 AM
Yeah, I do that. I was just curious if I could use that option, would have been a convenience - and found it odd that it would convert a 30fps project to 29.9 upon ingesting a 30 fps video ;)
musicvid10 wrote on 5/29/2014, 6:00 PM
It's because of x264, not anything Vegas can do.
Frans Meijer wrote on 5/29/2014, 11:33 PM
It is using Quicksync, not x264, but it got the frames from pc 3D rendering and variations in framerate will lead to getting frames not exactly timed at every 1/30 second intervals ... Other sources are fine, Vegas just doesn't like the variable framerate.
musicvid10 wrote on 5/30/2014, 7:17 AM
No.
You are using x264 ENCODING.
quicksync does not affect frame rate or the way it is reported by x264. How could it?
The encoding is constant frame rate, that gets reported as variable. This is abundantly documented.
If you want support, I suggest you start with a bug report to the x264 developers.
Best.
Frans Meijer wrote on 5/30/2014, 9:02 AM
x264 is a specific implementation of the H.264 specification. Intel's Quicksync another one, it was used to encode to H.264. The implementation named x264 did not get anywhere near the process.

Variable framerate is (probably) a codec feature and not just an implementation bug.