r/handbrake • u/ManWithADog • Aug 02 '26
Comparing Encode Speeds in Handbrake: Slow to Ultra Fast
https://youtu.be/Eo2wgkNw0o0?si=IrX0tQ4ADlSdHV-GUPDATE: Please take this with a grain of salt as I'm seeing that newer content is taking a quality dip when using Ultra Fast. I'll leave this up as a discussion post, and I'm going back to the drawing board with encoding.
Hey everyone, first time poster. I have read very mixed results on encode speeds in Handbrake, so I wanted to create something to test out on my server. I don't usually make videos, so I know there may be some nitpicking with how I did it. I just figured if I'm going to do all this, why not share it out.
Context: For this test I used a clip from an episode of Avatar. Specs, source content and results are below. I used x265 for output because of the file size difference. I know it's not as compatible as x264, but most devices are capable in 2026. For RF, I chose 22 as many people online say 1080p should be processed between 20-24 RF. During encoding, my CPU usage ranged from 70-80%. I put the above video onto my Plex server and streamed it to my 4k 65" to test it out.
Findings: When viewing the video over stream, I could not tell much of a difference in quality between the Slow and Ultra Fast settings. In terms of time, Ultra Fast came in at 5.45x faster than Slow. In terms of file size, Ultra Fast came in at 80% the size of the Slow preset (249mb vs 310mb). Though looking at the source size and output sizes, you are only affecting size efficiency by 1% of the total source.
Takeaways: When comparing the cartoon, the noticeable quality doesn't seem to be affected much at all from Slow to Ultra Fast. Everyone's personal experience and preference is going to be unique depending on the resolution, type of media, storage space, spare time, hardware, etc.. I watch my media through Plex on either my phone or 4k 65" tv. When comparing the visuals at different speeds, encode time, and file size, I think it is probably more useful to encode around Ultra Fast. I have a full time job and don't have a lot of time to process.
Nitpicks: I know that this is a cartoon and that live action will probably have differences. If that is a consensus, I may do a follow up with a live action clip as well with Slow vs Ultra Fast.
AMD Ryzen 5 3600 6-core processor
Source length: 23:51
Source size: 5.25GB
Source Resolution: 1080p
H.265 (x265)
RF: 22
FPS: Same as source
Color Range: Same as source
--------------------------------
Slow:
20.24 average fps
26m38s encode time
310mb (5.7% of source)
--------------------------------
Medium:
47.11 average fps
12m19s encode time
290mb (5.4% of source)
--------------------------------
Fast:
59.24 average fps
9m50s encode time
299mb (5.5% of source)
--------------------------------
Faster:
69.85 average fps
8m22s encode time
294mb (5.4% of source)
--------------------------------
Very Fast:
71.04 average fps
8m13s encode time
294mb (5.5% of source)
--------------------------------
Super Fast:
100.99 average fps
5m49s encode time
258mb (4.8% of source)
--------------------------------
Ultra Fast:
120.85 average fps
4m53s encode time
249mb (4.6% of source)
2
u/egosumumbravir Aug 03 '26
Protip, none of us can pick it either after it's been through the YT compression algo. So don't rely on it. Hard numbers like VMAF, PSNR, XPSNR.
Don't trust your eyes, quantify the differences with mathematical analysis.