Reference for expert tweaking

pystub

New Member
I accidentally stumbled upon this x264 analysis. It gives a good insight into advanced options of the codec. I managed to get rid of that awful image deterioration into blocks when low bits per pixel and high motion get combined.

If you're reading this and scratching your head unsure about what options it's being talked about here, I suggest to save your time and do something more fun.

Hopefully links aren't a banable offense here
Video Codecs Analysis and Tuning
Grab the report from the 2008. It may be dated, but it compares features relatively and after a bit of testing, the principles apparently stayed the same. The magic value that helped me was subme=4. It eats the CPU like mad at higher resolutions, but the quality gain is really noticeable.
I wonder if it would be possible to automatically adjust some of the encoding options mid-stream.
 

dodgepong

Administrator
Forum Admin
According to this, the "faster" x264 preset uses subme=4, whereas veryfast uses 1.

I don't believe it's possible to change x264 options while x264 is encoding.
 

softlight

New Member
pystub? Thank you SOOOO damn much...

i take my time to read the entire thing and test out different setups.
Now with my Settings changed to that pdf, my stream quality is better, i use less cpu power AND be able to stream even "new" games like SleepingDogs butter smooth in 720p on my old Q6600... its just amazing O.o on some days i even had problems to get a solid 480p stream, now its like i have a complete different cpu in my rig :O running like a charm
 

miTTPC

New Member
softlight said:
pystub? Thank you SOOOO damn much...

i take my time to read the entire thing and test out different setups.
Now with my Settings changed to that pdf, my stream quality is better, i use less cpu power AND be able to stream even "new" games like SleepingDogs butter smooth in 720p on my old Q6600... its just amazing O.o on some days i even had problems to get a solid 480p stream, now its like i have a complete different cpu in my rig :O running like a charm
Mind sharing these settings? :D
 

softlight

New Member
okay, based on stats:

for general streaming:
partitions=p8x8,b8x8,i8x8,i4x4 bframes=2 ref=1 me=hex subme=4 mixed-refs=off weightb=off

around 8% better codec quality and 16% faster encoding the same way.


for cpu heavy stuff:
partitions=p8x8,b8x8,i8x8,i4x4 bframes=2 ref=1 me=dia subme=1 mixed-refs=off weightb=off

around 5% worse encoding quality (but cant even see that) but 45% faster encoding.


Lately i had really big problems to stream minecraft cause of its java based. Even if i have 300fps ingame while streaming, it was stuttering like hell so i needed to switch it to 480p
With the second settings i run it smoother than on the old 480p and sitting on around 17% cpu load on obs and 54% cpu load at all...

i just love it

here´s a little capture from yesterday´s stream, pretty happy with it.
running on high, Q6600 OC@3,4 8GB DDR2 Ram and a GTX 650ti. 720p 30fps 2000kbps bitrate 2500kbit buffersize quality 8, AAC 320 Audio, veryfast with the second x264 preset i posted on top
http://www.twitch.tv/lolsoftlight/c/2423372
 

ball2hi

Member
I just did a few tests from 540p to 480p, ect. Unfortunately though, I don't believe I have the bitrate to do 540p at 10QB in an FPS game (2.1mb/s).

Here's a quick (But not similar) run-down in a very CPU intense place in L4D2. Something about it just uses so much more resources than most other areas:

General Streaming:
http://www.twitch.tv/ball3hi/b/420878517

CPU Heavy streaming:
http://www.twitch.tv/ball3hi/b/420884119

I have an in-game FPS counter in the top-left. It's green when it's above refresh rate, yellow when it's dipped below refresh rate, and orange/red when it's almost half my refresh rate. Two things I noticed right off the bat.

In the first stream, things look very clear. With the exception of resolution, it almost felt like I was actually there. My default stream had a bit of pixelation always during extremely intense scenes. I did not notice any, especially in full-screen mode. Unfortunately it suffers from what usually plagues me in that area. Lots of enemies, and that paticular rooftop spot, my FPS can be seen changing to orange/red regularly.

In the second stream, things look very similar to my usual stream. Slightly more grainy (Barely even noticeable) but as you can see in the top left my FPS barely dips into orange/red in the exact same spot as before.

Just a question though. I'm using "tune=animation" from http://obsproject.com/forum/viewtopic.php?f=18&t=4516 to achieve a strict CBR. Is this going to interfear with anything, do I actually even need it in custom settings since I already have bframes/refs set with the above settings?
 
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