I've been trying out many different programs for encoding AV1 format videos, however many of them had different issues like bad support, or being very outdated.
Then I found out Axiom, made by a fellow reddit user MattMcManis. It is a GUI for FFmpeg, it is very flexible compared to handbrake because it doesn't come with FFmpeg built into it, that means you can update them independently, always making sure your codec is up to date.
So I decided to contact Matt and was very impressed by the active support this program had, I even asked for a small guide on AV1 encoding and he delivered.
Beware because AV1 is still in an experimental phase, you will encounter some quirks, for now it seems FFmpeg doesn't support webm container for AV1, however mkv seems to be working fine. Also you might expect of the encoding to slow down at the very end, but be patient, it just got really slow, even for AV1 standards.
Things that you will need to start encoding AV1:
Nightly build of FFmpeg
Latest Axiom version
Extract Axiom, FFmpeg
Open Axiom
Axiom will automatically detect required FFmpeg files for encoding if the ffmpeg folder is in the same directory as Axiom.exe.
If it doesn't detect, then go to settings and locate FFmpeg, FFprobe and FFplay(They should be in extracted ffmpeg folder/bin).
You can also put the ffmpeg folder in your C:\Program Files and set your Windows Environment Variables to use ffmpeg, Axiom will detect it from anywhere.
And you are ready to encode, again if you want to check what settings to use, use this guide and if you need a user guide, you can find it here, which you can also find it in Axiom folder.
Big kudos to MattMcManis for making this amazing program.
If you encounter a problem, please post a comment detailing it, Matt and I will try our best to find a solution to it.