100Mbps, GOP3, AQ2, 7~9Mb I-frame... Hmmm... AQ3 is too much to ask? Go for it @driftwood!!!!

@VK

If you look up the QP numbers in the table (in the standard, that is) a value of 20 corresponds to a 5:1 compression ratio in I frames. An uncompressed 4:2:0 1080p frame comes to about 3MB. If you divide that by 5 you get about 600K - which is what @driftwood got (almost - but you have to account for overhead).

Assuming that B frames ideally come out to about 1/4 the size of I frames with GOP 3, that means GOP 3 will be about twice as efficient as GOP 1. Given that, the QP should be able to be set at 14. That will result in I frames of about 1.2MB and B frames of about 300KB at a bitrate of 100Mb. Setting AQ at 1-2 should get close to that, or QP can be set manually. Without also raising FB1, FB2, and frame limit about 1.5x, the codec will either not reach 100Mb, or B frames will become artificially large because I frame size will be limited to 1MB. Thus I believe that with GOP3 at 100Mb you pretty much have to increase quality settings to make productive use of the bandwidth.

Anyway, that's how I calculated it. That's why I like this stuff @driftwood is doing.

Chris

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

@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

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!

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

@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...

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...

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

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.

@driftwood

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

Chris

@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