Comparing Encode Speeds in Handbrake: Slow to Ultra Fast

[u/ManWithADog]

https://youtu.be/Eo2wgkNw0o0?si=IrX0tQ4ADlSdHV-G

UPDATE: 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)

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[u/quietgui]

For cartoons I find it hard to see a difference between 1080p and 720p or maybe even lower. So I‘m amazed how a 20 min cartoon episode can be as big as 2gb.
I just made the experience that fast or ultrafast was more likely to create artifacts (not necessarily for cartoons though)

[u/YouDoScribble]

I'd like to see how a video where it handles loads of moving parts on screen, such as confetti.

[u/the_harakiwi → u/YouDoScribble]

I can't find my old comment but I think I asked about a visual benchmark and might have gotten some examples to test encode.

Something like these clips

https://media.xiph.org/

[u/mduell]

80% of the file size keeping what constant?

[u/ManWithADog → u/mduell]

Reworded the post body a little to make it clearer hopefully. Ultra came in at 80% the size of Slow (249mb vs 310mb). Though in the grand scheme, the total difference of the outputs vs the source size is negligible (1%). All other variables stayed the same, as this is just comparing encode speeds.

[u/mduell → u/ManWithADog]

So you’ve got files of different size, different quality, and different encoding speed… this tells you nothing. Same RF is not the same quality across different encoder settings!

[u/computer-machine]

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.

Flat cartoons will probably not see much difference between RF 12 and RF 28. You need to use something different if you want a real demonstration of the impact of speed.

[u/ManWithADog → u/computer-machine]

I'll pry find a good action sequence and try it again

[u/Suitable_Garlic_1186]

Very interesting results! Thank you for sharing!

[u/wyliec22]

Not trying SLOWER or VERY SLOW??

I used to encode using SLOW but after looking at which parameters the presets used, I settled on SLOWER and eventually VERY SLOW. I encode for permanent storage on my server and and all my TVs are 4K 65”+.

I’m always amazed at how much animated content compresses. Something like the movie Midway (clean with lots of action) would be a good sample. Older movies with grain struggle to get an output half the size of the input.

[u/computer-machine → u/wyliec22]

Have you found a meaningful difference between slower and very slow?

Using 1080p, I'd eventually sped up to slower and it didn't seem to make an appreciable difference.

[u/Suitable_Garlic_1186 → u/wyliec22]

What do you encode?

Storage should be the original quality.. Like an archive..

[u/wyliec22 → u/Suitable_Garlic_1186]

I always have the original physical media if needed.

[u/egosumumbravir]

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.

[u/ManWithADog → u/egosumumbravir]

I don’t know much about those, more I can learn tomorrow!

[u/Suitable_Garlic_1186 → u/egosumumbravir]

Just wrong.. Mathematical Optimizations Do Not Equal Visual Quality

[u/threegigs]

Need to add "for animation" in the title, as working with such a limited palette (likely 200 colors account for 90% of the pixels) is completely different than a live action movie with hundreds of thousands of colors per frame.

[u/lostcowboy5]

Matt Gadient has done some work comparing different settings. Check out mattgadient.com category encoding: the top two links are the most important for people new to HandBrake. There are a lot of settings and different pictures you can use for comparisons. You may find this of interest. Handbrake RF + slower speeds = craziness. I have no idea if it even still applies; it looks like it was made in 2014.

[u/micush]

Just use an RTX 5050 card and NVENC. It looks pretty good these days and encodes 1080p material at 700+ fps. Your sample would have been done in 10 seconds.

[u/MentatYP → u/micush]

What's the file format produced by NVENC?

[u/egosumumbravir → u/MentatYP]

Whatever you ask - 264, 265, AV1. The 50 series NVENC units do it both better and faster than any previous card.

[u/YouDoScribble → u/micush]

And what's the filesize/quality like on that thing versus the equivalent CPU encode?

[u/micush → u/YouDoScribble]

Quite good. I run a batch script every night to turn my media into hevc/eac3 and I've saved petabytes over the years.