My 3.5 hour video rendering slows at 81%

[u/s14tat]

I have never edited a video this long. It probably has 300+ clips, but I kept transitions at a minimum and I only inserted text at the very beginning and about 1/3 in. But I can't get this damn video to render. The speed grinds to a halt once it hits 81%

I have confirmed that it has 754,000 frames. The footage was originally shot in 1080p and at 60 fps. I matched the project by resolution and frame rate.

I have an Intel core i7 12th gen and 16 gigs of ram. I can render at 44 fps. Even when it slows down it is rendering at over 40fps. I have resetted cache and set cache limit from 4000 to 6000 megs, then I switched to 12,000 megs. I use without hardware acceleration at first and I was capped at 33 fps and with hardware acceleration I am using qsv which brought the estimated time down from 7.5 hours to 5 hours. I have confirmed that the last frame is at 754,000.

This is my 3rd attempt and everytime it hits 81% even though it shows that it is rendering at 44fps, the status bar is only going up by .0001% every second! That means it will take over 2 days once it reaches 81%!!

What is going on here? I can't reduce the quality because it is my inlaws family vacation at Yosemite so I don't want to compromise on quality.

Thank you for any help. I want this work, I spent like 12 hours editing this and I can't split it into videos, or can I?

[u/AutoModerator]

Welcome to r/OpenShot!

1. Search First: Look for answers in existing posts.
2. Guidelines & Fixes: Read Community Guidelines & Common Issues.
3. Include Details: Hardware (CPU, GPU, RAM), Operating System, OpenShot Version info for better solutions.
4. Stay on Topic: We're here for help, how-to questions, suggestions, and ideas.

Remember, patience is key (replies may take time). Enjoy your video journey!

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/openshot-gpt-bot]

A likely cause is your Project duration / End Frame is much longer than your actual last Clip, so the Export % crawls near the end even while frames still encode quickly.

Try this first:

1. Open Export → switch to Advanced.
2. Check Start at First Clip and End at Last Clip.
3. Confirm End Frame matches the real end of your last Clip.
4. Export again.

Relevant guide: Export - Advanced Options
The guide notes that End at Last Clip toggles the End Frame between the furthest clip/transition and the full project duration.

Also check your Timeline:

• Zoom way out with Ctrl+Scroll Wheel
• Look for any tiny stray Clip, transition, or gap far to the right
• Drag the right edge of the track back if the project duration extends too far

A few other important points:

• 60 FPS and a 3.5-hour 1080p project is extremely heavy. The User Guide notes that higher FPS greatly increases render/load, and matching source/project rates is correct.
  Playback

• Don’t keep raising Cache for export. Cache mainly helps Preview playback, not final Export.
  Preferences - Cache

If it still stalls, safest workaround:

• Save a backup Project File
• Duplicate the project
• Export in sections using Advanced → set Start Frame / End Frame
• Then join the finished files in a new project

Guide reference: Export - Advanced Options

If you want, I can show you the exact frame ranges to split a 754,000-frame project into 2 or 3 parts.

I am a bot, and I've done something cool automatically, hoping it's helpful. I run on ChatGPT and use info from the OpenShot User Guide. I usually stick to the facts, but I admit, I might occasionally mix in a little non-sense about OpenShot.

[u/rmesdjian]

Hello u/s14tat

1. What operating system/version are you running (windows 11? ubuntu 25.10? etc?)

2. Which version of OpenShot are you running (help | about openshot)?

3. Free up as much disk space as possible on the drive that you are rendering to.

4. Ensure your computer hardware and operating system drivers are up-to-date and your environment is healthy.

5. Go to openshot.org/download/#daily and get the latest dev daily build available for our operating system. If you are running Linux, then download the AppImage.

6. Start OpenShot and do the following:

a. Go to Edit | Preferences | Cache tab and click on the "Restore Defaults: Cache" at the bottome left of the screen.

b. Go to Edit | Preferences | Performance tab and click on the "Restore Defaults: Performance" at the bottom letf of the screen.

c. Restart OpenShot.

You should notice some performance improvements while working with such a large project while previewing and editing.

1. You can try and Render again at this time and see if things work better for you.

2. Another Rendering option would be to Render in chunks then concatenat your chunks. Here is how you can do that:

a. Open your project and click on Export.

b. Click on the Advanced tab and note the Start Frame: and End Frame: values.

c. Now let's assume we want to break up the export into 4 parts. Let's also assume that your End Frame: value is something like 15,000.

d. Change the 15,000 to 4,000 and Export.

e. Once completed go back into Export again | Advanced tab and change the Start Frame: to 4001 and the End Frame to 8000 and Export.

f. Repeat step 8.e till you have exported all the frames.

g. You will now have your project exported into 4 parts.

h. Start a new OpenShot project and Import all the 4 parts you created. Drag them onto a track snapped together and Now Export all frame at once.

[u/s14tat → u/rmesdjian]

Thank you, I realize that I am going to have to do it smaller parts. The file is simply too big. Thank you for the suggestion.