Converting Variable Frame Rate Video to a Constant Frame Rate

wwaag wrote on 3/31/2019, 7:16 PM

Variable frame rate (VFR) video has been and still remains a problem for Vegas users. Although current versions do a lot better job of importing VFR footage, Vegas still prefers constant frame rate (CFR) video and there is always the possibility of duplicated frames. A recent thread with Samsung Note 9 footage illustrates the problem Two takeaways from this thread. First, there should be an easier way to test for duplicate frames rather than simply "eyeballing" it. And second, there should be a better way to convert VFR to CFR without having to transcode which can result in either extremely large file sizes or a loss of quality.

To address the first concern, I created an app called Duplicate Frames Finder (DFF). It uses some of the same code found in another tool, Render Quality Metrics (RQM), that I wrote last year

Like RQM, it requires the user to render an image sequence of BMP's for the test footage. The app then compares frame 1 with frame 2, frame 2 with frame 3, etc.

In the latest version of Happy Otter Scripts, there is now an option in the ImportAssist tool to convert VFR footage to CFR without transcoding. Only the internal timecode is adjusted--the audio and video remain unchanged. A demo of the both the DFF app and the conversion from VFR to CFR can be found here.

To date, I have verified that it works on Samsung Note 9 hevc, Samsung NX1 hevc, and iPhone avc. If you're interested in using the DFF app, you can download it in the Tools Library on the HOS website. There are also a few other freeware tools that are now available. If you want to test VFR to CFR conversion, you'll have to download the HOS package which will remain in beta through 15 May.

Comments are welcome.





Former user wrote on 4/2/2019, 9:46 AM

Hi @wwaag Thanks for these tools. I downloaded the mp4 date changer, but I see it needs the HO scripts package. Is this part of the main HO program? and so need to install all of it, or is it a smaller package?

The only scripts package I see in tools is the “Text script converter”.

I didn’t want to install HO until beta ends.

wwaag wrote on 4/2/2019, 10:45 AM

@Former user

"Is this part of the main HO program?"

Yes. I've included apps within the main HO setup program that are needed by some of these tools. In particular, mp4 date changer requires Exiftool by Phil Harvey to run. It's not only the tools but also the folder locations of where to find them. I found it easier just to have them all in the same location. Another app that requires the HO setup is the mp4 file joiner.

"I didn’t want to install HO until beta ends.". The way its going, that may never happen. LOL. I'll be putting out a new build in the next couple of days to fix some problems I introduced in the last version.

Former user wrote on 4/2/2019, 12:04 PM

Ok, thanks.