x265: a good compromise between "slow" and "slower" presets?

iz-Moff · 12th October 2019, 18:17

Hi.

I wanted to do some encoding using x265 (ver 3.0), but i can't quite decide on the settings. Preset "slow" has pretty good encoding speed, enough that i wouldn't mind sacrificing some to get a bit higher quality encodes, but the next available preset is like 3-4x slower, which is way too slow for me.

I want to tune "slow" preset to be a bit closer to "slower", and i've looked up the parameters they use, but i'm not sure which of them would offer a good tradeoff between speed and quality. I tried reading docs, but they're too technical for me to understand and don't really offer any advice.

So i was wondering if anyone could give me a rough outline of which parameters would have what effect on quality/encoding speed?
Thanks.

Here's the list of parameters that are different between the two presets:

Code:

				slow	slower
bframes				4	8
rc-lookahead			25	40
lookahead-slices		4	1
ref				4	5
limit-refs			3	1
subme				3	4
amp				0	1
max-merge			3	4
recursion-skip			1	0
b-intra				0	1
weightb				0	1
rdLevel				4	6
tu-intra			1	3
tu-inter			1	3
limit-tu			0	4

12th October 2019, 18:17	#1 \| Link
iz-Moff Registered User Join Date: May 2014 Posts: 3	x265: a good compromise between "slow" and "slower" presets? Hi. I wanted to do some encoding using x265 (ver 3.0), but i can't quite decide on the settings. Preset "slow" has pretty good encoding speed, enough that i wouldn't mind sacrificing some to get a bit higher quality encodes, but the next available preset is like 3-4x slower, which is way too slow for me. I want to tune "slow" preset to be a bit closer to "slower", and i've looked up the parameters they use, but i'm not sure which of them would offer a good tradeoff between speed and quality. I tried reading docs, but they're too technical for me to understand and don't really offer any advice. So i was wondering if anyone could give me a rough outline of which parameters would have what effect on quality/encoding speed? Thanks. Here's the list of parameters that are different between the two presets: Code: slow slower bframes 4 8 rc-lookahead 25 40 lookahead-slices 4 1 ref 4 5 limit-refs 3 1 subme 3 4 amp 0 1 max-merge 3 4 recursion-skip 1 0 b-intra 0 1 weightb 0 1 rdLevel 4 6 tu-intra 1 3 tu-inter 1 3 limit-tu 0 4 Last edited by iz-Moff; 12th October 2019 at 18:45.