More Settings box and tuning parameters

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Leprechaun
Posts: 5
Joined: Sun Jun 12, 2022 11:05 pm

More Settings box and tuning parameters

Post by Leprechaun »

Is there any information about what goes in the More Settings box?:
HandBrake version 1.3.1
Linux Mint 20.3 Una, 6 core AMD cpu, 16 GB memory:

I am primarily interested in getting good quality videos compressed as much as reasonable, which is why my personal default preset is:

Super high quality H.265 video (up to 1080p) SRC framerate, 10-bit, RF=20, AAC stereo audio, and Dolby Digital (AC-3) surround audio, in an MP4 container. Constant quality preset SLOW. Deblock 5, Denoise HQDN3D Medium, ref=5:bframes=5

I picked up that last part about the filters from some else's post, but have no idea what they mean. I've found similar posts suggesting different filter settings:

rc-lookahead=120:bframes=12:ref=6:subme=7:aq-mode=3

AND

strong-intra-smoothing=0:rect=0:aq-mode=1

I've also read that if the source is high quality and not interlaced, it might be best (as well as fastest) to just leave everything off. That makes sense regarding the Denoise and Deblock settings. However the lookahead parameter seems to suggest that encoding could be sped up by prereading more of the movie. Likewise the ref and bframes parameter might affect speed as well as quality.

The manual doesn't have much information on these items. Does anyone have some explanations or suggestions to offer?
mduell
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Re: More Settings box and tuning parameters

Post by mduell »

Don't use a bunch of arbitrary settings you don't understand.

Use the encoder presets system to match your desired encoding speed, and the relevant tunes for your content.
Leprechaun
Posts: 5
Joined: Sun Jun 12, 2022 11:05 pm

Re: More Settings box and tuning parameters

Post by Leprechaun »

In the absence of an explanation of the various settings, I have conducted tests to attempt to determine their effects. Yet given that a test run might easily take days, only so many can be tested.

Nevertheless, the REASON I asked the question was to see if someone could explain them, or at least provide a link to an explanation. Right now I am interested in anything that could speed up or increase compression using look ahead, larger buffer size, or something similar to take advantage of the hardware I have.

Is it really useful to tell someone to not use anything he doesn't understand, without providing any information?
rollin_eng
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Re: More Settings box and tuning parameters

Post by rollin_eng »

https://x265.readthedocs.io/en/2.5/cli.html

You don’t have to encode a long video, just choose a shorter section that should represent your typical encode.

But what mduell said is correct, just use the defaults unless you have any reason not to.
Leprechaun
Posts: 5
Joined: Sun Jun 12, 2022 11:05 pm

Re: More Settings box and tuning parameters

Post by Leprechaun »

I appreciate the link you posted. It is one I have already found, and what encouraged me to ask the question above.

The link indicates that setting --lookahead-slices to 8 (the default) is faster than lower numbered settings. Since the upper limit is 16, that suggests that 16 might be even faster, and a new computer I am building just happens to have 16 cores and 32 threads. This is the kind of information I want, and I'll run random test picking numbers out of thin air if that's what it takes.

For example, I'm running a test now, RF=30 and settings: rc-lookahead=60:bframes=12:ref=6. I'll label it appropriately then try again, probably RF=24.

I appreciate the responses, but frankly I don't understand why anyone wouldn't want more information about a tool they are using. Those settings are there to do something, and the more I know about them, the more satisfied I am going to be using the tool.

Thanks again.
rollin_eng
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Re: More Settings box and tuning parameters

Post by rollin_eng »

Leprechaun wrote: Mon Jun 13, 2022 6:22 pm I am primarily interested in getting good quality videos compressed as much as reasonable
This is exactly what the presets are designed to do.

If you have an issue with a preset not giving you what you want then post your issues and people will help you, and many do because everyone has different requirements.
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