Question / Help x264 CPU Preset question

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Crabby654

New Member
So me being a noob to streaming and broadcast software I had a quick question about the presets.

Will changing the preset to a slower setting affect the upload or viewers download at all? I feel like my computer could handle the slow settings but I am worried that it might cause skipping or lag for viewers. Or does the slower presets only affect the CPU usage?

Basically my goal is to get as good quality 720p as possible but I'm not 100% how to reach as good quality as I've seen in other streams.

i7 2600k @5Ghz
EVGA 670 GTX
 
M

Muf

Forum Moderator
There are two ways in which a slower preset can cause a stuttery stream: it can reduce the framerate in OBS, which you won't see in the game but you will see the fps counter in the bottom right of the OBS window go below your specified framerate, or it can slow down your game (as OBS is fighting with your game for control over your CPU), which you will be able to notice while playing your game. You can experiment with different presets and see how they affect your stream and game fps to find a preset your PC can handle smoothly.
 
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Bensam123

Member
I believe the parent was asking if the encoder preset has any effect on the viewers computers. Like a higher preset puts more load on their computer when decoding. I'd personally like to know this too.

Does a slower setting increase the quality only if you don't have enough bandwidth too? Or is it possible to brute force this with enough bandwidth to the point that the encoder preset really doesn't make a difference?
 
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Crabby654

New Member
I've yet to test it yet but for some reason with my 11Mbs upload speed and bitrate at 3000 and 720@60fps people got skipping so I set it 45fps and it stopped skipping. But I am not super satisfied with the over quality which is why I want to try the slowest setting and see what that does, but ya I've yet to try. Maybe I'll steal my moms laptop and view the stream from their and see what happens.

EDIT: Interesting, I just gave it a test from my mother laptop watching it and there was no skipping with 720p@60fps and 3000 bitrate. However when I went to the slow setting i noticed almost NO increase in quality and it was insane skipping all over the place while viewing it. Hmmm, just seems blurry to me.
 
Krazy

Krazy

Town drunk
Lowering the preset lets you save maybe 150-200 bitrate. The increase in quality is not really worth the performance hit to your machine at all.
 
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micechal

Member
Bensam, using slower preset makes it slower for viewers to decode it too because of for example CABAC. With slower preset, you are trying to compress it more using heavier algorithms, so heavier algorithms are required for viewers too, but I don't think they'll notice any change with today computers.
 
L

Lain

Forum Admin
Lain
Forum Moderator
Developer
It shouldn't affect upload, it generally just changes the way it encodes.
 
yanis31

yanis31

Member
Krazy said:
Lowering the preset lets you save maybe 150-200 bitrate. The increase in quality is not really worth the performance hit to your machine at all.
Click to expand...

i know that's an old post but it sounds highly ignorant to me... (ofc correct me if im wrong)
i cannot stress enough how much better the slower profiles make the stream look.
i am using "fast" for 30-60fps 720p streams (depending on game) 3000-3500kbps amd fx 8 core @ 4.7ghz
and the quality is noticeably better, adding 200 bitrate does not seem to have nearly the same effect,
and plus my main goal is to keep the same quality with a somewhat lowered bitrate because alot of viewers from usa cant handle my streams altho they work just fine on my end... i will upgrade to atleast a intel 6core/12thread cpu at the first opportunity so i can push the presets even lower - so i am genuinely concerned whether this affects viewers with older hardware / mobile devices...
heck we even figured out decent looking stream settings for a friend who's stuck on 1megabit upload and also has fx8core using the slowest profile (on lower res/bitrate those profiles are easier to handle)
 
A

alpinlol

Active Member
in theory the only hits the viewer gets are cause by the flash replay this means the resolution and bitrate

if you are streaming with a 3500 bitrate your viewer needs AT LEAST 4mbit as download to somehow watch the stream since there will always be some bitrate spikes but this is in theory not even the biggest problem

the real problem is the flash player itself if you are streamin 720p30 everything is fine the cpu hit caused by flashplayer on your viewers end is just a margin and not so bad but as soon as you start 720p60 there will be a noticeable change worse it can get right now is 1080p60 this can max out some intel celerons or x2 athlons if your viewer is watching with a browser like chrome and is running the build in chrome flashplayer

done those testings my notebook can barely handle 720p60 on the viewers end with an intel c2d t6570 yes this notebook isnt really good and is about 5-6 years old by now but still it literally maxes out on cpu usage just by watching a 720p60 stream and this causes really bad lags on the viewers end

presets will only affect your system performance
 
yanis31

yanis31

Member
well yes... i have a core i3-380m laptop and it cannot handle my 720p/60fps streams.. sometimes it keeps the 60fps... sometimes goes as low as 40fps and drops frames...(stream runs fine on my pc next to it at the same time) fullscreen is even worse... but i suspect the intel graphics to be a part of the problem... also tested a core2duo e6600 (4mb cache/2.4ghz) overclocked to 3.0ghz / 333fsb) and it can barely handle the 60fps... still loses some frames... at stock 2.4ghz its miserable... cpu usage @ ceiling :(
 
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