Question / Help pixelation why!?

M

mmaxt

New Member
I've noticed that my image quality in my stream is really poor. I get high amounts of pixelation regardless of the resolution or frame rate. My download speeds are 50Mbps and my upload is 11Mbps
basic specs and stats:
CPU: AMD FX-8320 @ 4.5Ghz
OS: Windows 8.1
RAM: 16GB DDR3 1866Mhz
GPU: MSI R9 280X
HDD: Kingston 112GB SSD

OBS SETTINGS
Bitrate: 3500, Buffer Size: 3500
Audio: 160
resolution 1920x1080
Process priority class: high
x264 cpu preset: very fast

why is this happening and how can i fix this?

http://www.twitch.tv/mmaxt/profile/past_broadcasts
The most recent broadcast is 30fps 720p
the second most recent is at 30fps 1080p
i see no difference =/

any help is greatly appreciated
 
dodgepong

dodgepong

Administrator
Community Helper
Looks pretty normal to me. I think your quality expectations of livestreaming are too high.
 
M

mmaxt

New Member
i believe its this video http://www.twitch.tv/mmaxt/b/388448355

i've been tweaking the settings and testing, but no luck
i REALLY want to figure this out
i've tried changing the bit rate, lowering the resolution, cpu priority
and this link to my old video... i was streaming on my now secondary computer (a lesser computer) but the quality is better
 
M

mmaxt

New Member
actually i think it is the wrong video, but it should still be configured the same.
i calculated for a proper "quality" bitrate at about 4148
i know twitch recommends 3500, but you wont get 0.1 pixels per frame with that bitrate

Let's say you want each pixel to have a "quality" of 0.1 bits (the default used in the Twitch SDK), this is how you calculate the bitrate: (width x height x fps x bits-per-frame) / 1000

(1920 * 1080 * 30 * 0.1) / 1000 = 4148 Kbps

i even tried it at 720p with the bitrate at 4148 and it still looked incredibly pixelated...
do i need to downscale more? can i lower the bitrate if i do so, without losing quality?

EDIT: i tried streaming at 960x540 http://www.twitch.tv/mmaxt/b/562920327
and here it is at 1920x1080 http://www.twitch.tv/mmaxt/b/562898484

at 1080p there is a noticable amount of pixelation, but the overall quality feels better?
lol i dont know what im talking about
 
Last edited:
Jack0r

Jack0r

The Helping Squad
That is why we mostly recommend 720p as the middle way. It will give you a relatively good overall quality while it also will pixelate a lot less than 1080p content. The calculation is nice and all, but is not accurately what x264 will want/need to produce a "perfect" picture. So I mainly keep to the usual values and test which works best for me.
Set your stream to 720p and try 2000 / 2500 / 3000 / 3500 and 4000 bitrate for example. You will notice that the quality increase you get in the later stages is not enough to justify the high bitrate. Around 2500-3500 will be the best value.
 
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