Create MP4 Issue - same project taking several more hours to compile

A_Colonna Website User Posts: 9


This one has me stumped!!

So I was up past midnight finishing a 4K project. All transcoded footage GoPro Cineform 10bit.  It's just over a 40 minute video generating as YouTube 2160 UHD.  I started it compiling after midnight and this morning around 8AM it was finished. Just under 8 hours.

After previewing, unfortunately I had to fix a couple things, and started recompiling the project at 11:15AM today. Well it's been 5 Hours 53 minutes compile time and it's only at 52%!! I fully expected to upload to YouTube today, but no way now.

How on Earth can it be going on 6 hours and only at 52%? The whole 40 minute video compiled overnight in less than 8 hours.. I'm just flabbergasted here. The estimated remaining time is still 5 hours.  That's nearly 11 hours compile time, when again it compiled the first time in less than 8 hours.

Anyone else ever seen this? Did I need to reboot first or restart Hitfilm Express? Ugh.

Thanks all,



  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 19,815 Ambassador

    Estimates are estimates and are based on the time to render the CURRENT FRAME. If, for example, the first half of the video has a lot of effects work and the second half doesn't, then you might find the time estimate dropping quickly once you get past the FX heavy bit.

    And sometimes this goes the other way... Oh, this will render in 5 minutes... *render hits the massive particle sim* Oh, this will take 2 hours!

    Otherwise there are too many variables for us to know what's going on here. Something could have decided to update elsewhere on your system.

    I assume the first render you went to bed. This next render... Are you doing anything else on the machine? Like writing this very forum post? If so you're diverting resources from Hitfilm, increasing render time. 

    Some of the things you changed in the project might be affecting render time. As an example, maybe you had something Pre-rendered but changed something that would effect (invalidate) the Pre-render, which increases render time. I've done that myself. Or you've added a "simple thing" that's actually resource-intensive (for example, try to never use Levels Histogram... Use Curves instead. The Histogram read back makes a "simple" Levels adjustment slower rendering than doing it with Curves). 

    So, yes, I've had times when I did a render, then a change, then a re-render and had the re-render take longer. The above examples all have happened to me. None are a Hitfilm "bug," but are some factor that changed render time. Not just "taking forever to render for no reason."

  • A_Colonna
    A_Colonna Website User Posts: 9

    Thank you for the reply! In all honesty, I did a test upload to YouTube, and found a Copyright claim. I failed to notice one bit of background music that I hadn't noticed before. So I edited the video, took down the volume of the video track, and inserted music I'm paying monthly for.  I also trimmed down one sequence a tiny bit.  It's at 56%, and while yes I am writing this on the same computer, the computer has mostly been untouched today as I worked on my business computer, and let it do it's thing.

    Would exiting Hitfilm Express and relaunched have done anything? I'm not sure what else I could have done to make it so much longer. :-(

  • A_Colonna
    A_Colonna Website User Posts: 9

    Hey Triem23, so it did compile in 11 hours, so about 3 over the original. Who knows what went on, maybe some clips did decompile. Anyway, in case you're interested in a quick peak, here's the vlog.. We've had the most comments and views ever in 1 day!  Happy about that!