I edit most of my videos on Linux using Kdenlive.
Kdenlive is probably the most powerful and popular open-source non-linear video-editor, but one feature that has been spotty is hardware-acceleration. Many releases back this functionality was partially available via the Movit library, but I could never get it to work. Apparently other people also had issues with it because they removed it for several releases after that.
With Kdenlive 21 I started seeing new options for GPU/Hardware-Acceleration, but they weren't available in the AppImage version of Kdenlive.
In version 21.11.70 they became available, but it wasn't until my last video that I remembered to give it a try.
My System:
On my studio system I'm using an Nvidia Quadro K2000. It's not a gaming GPU, but a workstation card for professional shops. I got this system from the woman I was dating who worked for a firm that designed restaurants, bars, and kitchens at 5-star hotels, Disney parks, even the cafeterias at Google and Yahoo's campuses. They were going to throw this workstation away, and so it became mine thanks to her.
This means that with an Nvidia GPU you want the NVENC(Nvidia-Encode) profile. On AMD, and probably Intel graphics hardware you'll want to use VAAPI.
Results:
I had just completed editing my video about Gettr, Rumble, and 3Speak (I'll be uploading it to Dtube soon, and to 3Speak a little later) it's 1920x1080 and I always render to MP4 which was available with NVENC, and so I figured why not test it out.
Normally when I render MP4/x264 my CPU runs pretty hot. Up to 80-84 degrees Celsius. It's an older Intel Xeon, and I believe the maximum temperature junction is 90 degrees Celsius. When rendering with the CPU when it reached 82 all of the system fans would kick up to max and run constantly until it started to fall back into the mid-70's range.
With NVENC the GPU barely breaks a sweat at 83 degrees. For comparison the GPU's TJ-Max is at something like 96 degrees. I opened up my Nvidia-Xserver app to monitor the GPU during the render. The Video Engine Utilization fluctuated between 86% to 100% and the entire render took exactly 8 minutes and 33 seconds:
So there we go. Kdenlive officially has GPU accelerated rendering. Pretty amazing stuff. Kdenlive have improved so much since the beginning of the pandemic that I've done several videos on major release points for the project.
And as of right now I haven't even tested out the latest version which is also a major update release.
I don't switch versions while I still have major projects started in an older version.