Official Low GOP topic

cbrandin

@driftwood

well... if you are going to go that far try upping FB1 FB2 and frame limit to 3x.

Chris

stoney

@stefanos You got it.

@driftwood 200Mbps sound scary!!! 110Mbps gave something close to 115Mbps average video rate.

I did some motion test. When a camera is stable and taking detailed scene, I-frame stayed around 9Mb. As soon as it began moving, I-frame size dropped and B-frame got beefed up where the size of I-frame kept above B-frame. Max B-frame size stayed around 5Mb. As soon as the camera was stabilized and focused on a detailed scene, the I-frame size restored to 9Mb and B-frame size got tamed to little above 3Mb.

The codec worked beautifully. I'll get some beer and celebrate. Gotta order Rokinon 35mm, too. Double celebration WooHoo!!!!

driftwood

@All Here's a GOP3 test to keep you up. videobitrate 24H = 200mbps. Pappas death chart stable.

cbrandin

@stefanos

Yes, the GOP 3. I think it will keep up with motion just fine. Also, the individual frame quality will be better than is possible with GOP 1. It's perfect for me.

Chris

stefanos

@stonebat thanks, so GOP1 is probably a bit more geared towards motion improvements and GOP3 bit more for static detail improvements?
@cbrandin the GOP3 right? :)
@driftwood thanks again.

cbrandin

@driftwood

Magnificent! I think you just came up with my new personal settings. Thanks.

Chris

astraban

Stop beeing so emotional @driftwood !! Joking, well done sir, thanks.
Edited : nevermind my question...
Thanks again (thx also to the Musketeers who helped!)

stoney

GOP1 might have much less motion artifact as there are nothing but I-frames, but it lowers the bit size of I-frame.

GOP3 might have little more motion artifact as there are B-frames, but it raises the bit size of I-frame.

stefanos

@driftwood
thank you for your efforts dude! very cool, will test tomorrow.
can someone briefly explain the differences between 100mbps GOP1 and GOP3- pros + cons please?

stoney

@driftwood You did awesome job. Thanks man. 100Mbps GOP3 AQ2 Stable Cadence!!! 110Mbps worked fine, too.

driftwood

@Stonebat - I feel a little taken aback by VKs comment earlier. Ive been toying with a ton of settings before I settled on the 24p Video Buffer being my main problem - but it got me to 100mbps on GOP1 and GOP3. If other more experienced ptools users can take it further then fine! The settings I posted were always geared towards 1080/24p 24H. In future I wont check (or leave unchecked) settings not required. Sorry once more VK.

stoney

I hope somebody tests this case, too.

Take high details on a tripod. Wait 30 seconds. Start panning. Not too fast. Just slow enough to keep the I-frame size high. Not too slow. Just fast enough to raise B-frame size. That will stress the codec. Actually this case seems very practical...

stoney

Awesome. Can you try motion, too? Just move around and see how the sizes of I and B frames change.

The more details, the higher I-frame size. The more motion, the higher B-frame size.

driftwood

@Stonebat heres the 100mbps death chart with all of settings PROPERLY checked! Ill try pushing the bit rate more but we're probably hitting ther boundaries soon...

stoney

@driftwood Waiting for your pappas chart of death test result. Please post your settings!!! It will be super

driftwood

@Vitaliy_Kiselev You are being a bit harsh?! I forgot to check those FB & limits in my last tests thats all!

stoney

I think... 100Mbps is getting choked. Raise the overall rate more.

Video Bitrate 24H=110000000
1080p24 T4=1080p24 T1

driftwood

@stonebat Nice! I tried chris exact settings for FB1 FB2 and Limit - the result is the pappas chart of death below, as u can see the i frames stabilise to the same size as the B frames.

Note: ignore last test - redoing it - i forgot to check a few boxes, now Im getting f*ckin grief!

Vitaliy_Kiselev

1080i50 and 1080p24 GOP Size=3
Video Bitrate 24H ADD=100000000 < -- remove this
Video buffer=0x3000000 < -- not necessary
Video buffer 24p=0x3600000
1080p24 FB1=1175040 < -- FB2/FBL absent

@driftwood
You are full of posts and emotions, but very low on value.

driftwood

Chris, ta for the FB tips. Charts below = Latest GOP 3 Test. Pappas Death Chart 2 min test = Success. FB1/FB2/FB Limit 1.5 multiplier. The I frames have dropped btw - The images look G-R-E-A-T!!! Here's the latest settiings attached. Enjoy!
(NB this test was conducted only for 24H 1080p24)
Note: Sorry forgot to check the boxes for FB2 and Limit. I'm tired VK gimmee a break!

stoney

@driftwood Try exactly as Chris and VK advised. T4=T1, 1.5x on FBs and EFL, AQ2. Also 110Mbps!!! It passed my bush of death test.

cbrandin

@driftwood

You're getting a little detail pulsing there - maybe drop AQ to 2? Have you tried setting FB1, FB2, and frame limit to 1.5x the default?

Chris

driftwood

GOP3 100mbps with QA = 3. Pappas chart = Success.
VK / Chris: 1080p24 T4 = T1 - any recommednations?

driftwood

@bannedinv Go for it. 3 GOP looks stunning! 1 GOP is incredible too.

bannedindv

@ driftwood : Testing your settings with 100mbs - gop1 high and 50mbps gop1 low now

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