GH2 Maximum Variation Experiment

driftwood

@proaudio4 Yes!!!

proaudio4

So, that's all you changed in Chris's settings, the Video buffer 24p to 3600000?

driftwood

@proaudio4 Yes, changed to 3600000... Still on 720p stuff so I havent got time to look at 88M - I know you and Stray are working on that - maybe you should follow Chris's lead here and look to adapt his settings for 88M. But try it on the 360000 vid buff too. Could get really good results.

proaudio4

thanks

I take you left Chris's settings and only changed Video buffer 24p to 3600000?

driftwood

@proaudio4 the last test was.

driftwood

@cbrandin
66M on the Driftwood favoured 36000000 video buffer. Same conditions as other tests. Safer bandwidth - better results - both on 0.53 crb delays with zero errors.
Chart 1 OIS on 14-140 lens, 125 Shutter/800ISO Well Lit Room. The magic 0.53 delay. No removal delay errors.
Chart 2 OIS off 14-140 lens, 125 Shutter/800ISO Well Lit Room. The magic 0.53 delay. No removal delay errors.

Magic! Both Very good. :-)
And still a bit more room to push it :-)

proaudio4

driftwood, was this at 3600000 buffer?

driftwood

@cbrandin 66M tests on 0x2400000 video buffer (same conditions as 44M)
Chart 1 OIS on 14-140 lens, 125 Shutter/800ISO Well Lit Room. very faint change in highlights (brighter) around 14 seconds.
Chart 2 OIS off 14-140 lens, 125 Shutter/800ISO Well Lit Room. fine it takes me a few secs to move away from camera. The magic 0.53 delay. No removal delay errors. OIS off wins. :-)

Overall, I think things are fine.

driftwood

@cbrandin I know you dont seem to use the 3600000 buffer but Im gonna give it a whirl changing it after this next test. I just find it more stable (more bandwidth). In theory you shouldnt have to... but who knows...

driftwood

@cbrandin Gonna repeat the same test for 66M. Just in case.

driftwood

@cbrandin 44M tests on 0x2400000 video buffer: tripod, Pappas Death Chart, unattended for 3 mins both tests.
Chart 1: OIS on 14-140 lens, 125 Shutter/800ISO Well Lit Room.
Chart 2: OIS off 14-140 lens, 125 Shutter/800ISO Well Lit Room. No movement whatsoever/no light change/ I can send you the mts file for proof. But its weird what happens at frame 3630 onwards - the picture does NOT change I watched it continuosly with streamparser.
Note: Focus mode on all tests set to 25 (giving 50mm!!!)

Overall, I think things are fine.

driftwood

@cbrandin OIS on. Lights fully up in room. just left it going (unattended no moving around it) for 3 mins. Ill try any tests you want. Let me know. 44M Coming up in 5 mins.

Ill do two OIS off shortly - one for 66 and one for your 44m setting.

cbrandin

@driftwood

Thanks for the test. Any movement or light changes during the test? What focus mode was the camera set to? Was OIS on or off?

Chris

driftwood

@cbrandin here's the 66M death chart FYI. Looks good but could be some cadence issues as u can see. Test was conducted on 14-140 lens on a tripod, nearly 3 mins, 125 shutter at 800 iso.

Ralph_B

I'll run HDMI comparison tests as soon as I can, but very busy right now...

nic2011

@cbrandin
>>So far I have not been able to increase the 50/60p settings more without instability.>>

Too bad! I´d really appreciate such a patch with a higher bitrate (45-50) for 720p50/60...

cbrandin

@LPowell

The point of this experimantal patch is to allow the codec to use higher QP values if it can and still maintain quality - sort of the opposite of what you are suggesting. You really don't want to restrict the range more than the default - which is a range of target QP-2 to target QP+2. What happens if a frame runs out of bandwidth is that a fallback Quantizer scaling matrix is used to lower bitrate instead - and that looks terrible (severe macroblocking in lower parts of the frame). The 66M patch allows for a range of target QP-2 to target QP+10 (approximately).

Chris

cbrandin

@nic2011

So far I have not been able to increase the 50/60p settings more without instability.

Chris

cbrandin

@feha

Here is the 44M version of the experimental patch.

Chris

feha

@cbrandin

can you make same for the 44 mbps version ?
please .ini
Thank you

driftwood

@LPowell no. I attempted this. You can try Initial Q to say 18 and then Q to any higher setting to attempt a range. But generally, Ive seen most of the macroblocks return +- 2 Q of the Q setttings. Give it a try.

LPowell

@cbrandin
For high-bitrate settings, do you think it may be effective to set a cap on the maximum QP value the encoder will use on the lowest quality macroblocks? At 75Mbps with the pro version of MainConcept's H.264 encoder, I've seen some improvement in shadow detail by lowering the max QP from 51 to 32. Is there a patch in PTools that sets max QP?

driftwood

@cbrandin It looks stable on the charts Chris. We're gonna need some YUV comparisons - Ralph?

Stray

@cbrandin have you a version of your original 44M AQ4 and 66M AQ2 that uses the smaller FBs and Framelimit, now it seems that a bitrate multiple isn't required ? Or are we finding through testing this setting a better approach to patching altogether (as in letting the codec do the work of managing the allocation of the available bandwidth, instead of limiting it to a small range of QPs) ?

nic2011

Is it possible to get that patch with a higher bitrate for 720p50/60? I would like something around 45mb...

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