Only one core used during Export

Hi all!

I am new to Shotcut and so far really enjoyed working on it. Down to the step of exporting my video I realised it was taking really, really, really long.

Had a look in Hardware Monitor and realised that only one core of my 12 cores Ryzen was at work, no matter which format I was exporting it.

I just don’t get it, is there a way to unlock this situation? This software is brilliant but if it takes 24 hours to render a 1 hour video… kind of a deal breaker to me… Got a Ryzen 1600 and 16 Gigs of RAM so really the hardware isn’t an issue there.

Thanks in advance for the help.

Nice rig. Lots of cores! I want one. [grin]

In the Export window, Video tab, is Parallel processing checked?

During Export all 4 cores of my AMD A8-7600 are nearly maxed out.


No it isn’t as when it is it makes the export fail all the time :confused:

OK, something else is going on. You need to troubleshoot for what that is. Suggest creating a new project and use small clips, testing the codecs and settings to see what works and what doesn’t.

You should leave the Parallel processing checked all the time - so set it and start testing. You didn’t say what OS, Shotcut version, source clips, Export to what, and so on. Try something real basic with no custom settings and report here for more help. Good luck!


I use Windows 10 64bits, the source clips are mp4 and I already tried different “basic” exports like Youtube or simply h264.

If you are using “basic” Export settings then I would be suspicious of the mp4 input file. What is the source of the mp4 and does it fall within the parameters of being standard or is it proprietary? Some mp4 files have a variable bitrate that can sometimes cause editor problems.

Here are some sample videos online. Try these in Shotcut to see if it runs and all the cores are utilized.

Edit: Shotcut could be described as a visual front-end for FFmpeg. Looking over the FFmpeg docs I see that it can examine the resources and determine for itself how many threads it can use - which varies depending upon the Export codec. Your Ryzen processor has 2 threads for each CPU core so it supports 24 threads!! Unfortunately, however, FFmpeg may not be able to use them all. I was hoping, at the resolution to this problem, that you might happily report your system monitor showing 24 CPU processes for your video. Hardware wise, I think you may be ahead of the development cycle a bit. Even worse, Shotcut only supports ONE thread for Zooming the Timeline and rebuilding audio waveforms.