Official Low GOP topic, series 3

jfro

@onlocatoin On the transcend cards, I've found the orange label class 10 cards aren't as fast as the same card with the dark (blue or maybe black) label. I'm going to see if they will swap out my 3 orange cards for the ones with the dark labels.

jfro

@driftwood. I'm pretty comfortable with your Quantum V2 patch. I use the mjpeg for 2fps time exposures. Is there any known problems or gotcha's with V2 in regards to avchd in:
1080 24p h or L
1080i
720p modes

chauncy

@sharpixels
pretty sure sharpixels is trolling.

If not, he's incredibly arrogant for a first poster to just roll
on in with his great patch
that looks worse than stock.

He already tried to start his own thread with his patch.

It takes a lot of trial and error and learning to do a patch. I think he's
just trying to bash things rather than do anything useful.

kholi

Of course he's trolling. Looks like a consumer video camera.

Hope no one installs that on their camera. Brick City...

danyyyel

I would like to ask if need be a second set of Quantum patch more like V2 where you have a high 160 and a low about 60. My reason is than an L setting at 100 is too high compared to the 160. For some it might be good but for me it like a middle way that does not warrant me to go lower for the size compared to 160. While the 60 makes more sense because it is definitely lower so it will make a good difference in size even if you have to make some compromise in quality. But at least you have two clear choices. I am not saying that we should not have a 100mbit choice but both version for those that want it. Thanks again for the fantastic work.

balazer

@danyyyel, you can very easily change the 24L setting to anything you want in PTool after loading the Quantum settings.

driftwood

We need more feedback on any of the 720p60 and 1080i modes in Quantum betas, if anyone has any particular findings please let me know here. Together we can all make Quantum a great all round patch.
Indeed, we should all prefer to call it the 'p-v Quantum' patch as so many have helped and reported back findings. Any great settings should be presented with its case regarding the findings.
At the end of the day, if there are better settings/use of GOPs in different modes, then sobeit.
Many thanks. Nick

johnnyblank

Firstly thanks to @Vitaliy_Kiselev, @driftwood, @LPowell (for all those great GH1 patches) and everyone else who has worked on turning these cameras into filmic powerhouses and I hope this is an appropriate place to post this question.

I'm about to shoot a feature doco on two hacked GH2's (starting in the next day or so) and have run tests on Aquamotion, SeaQuake etc. I'm still having difficulty deciding on the best patch that combines stability/quality. We had some failures with Seaquake at 24h. Aquamotion seemed very reliable and spanned well. Just wondering if any version of Quantum would be better combination of quality and reliability? It seems a number of people have had success with v2 of Quantum. It would be awesome to have the high quality setting alongside the lower quality spanning (for interviews etc) in the one patch. Can anyone recommend which patch might suit the demands of a documentary best. I'd really welcome any input or advice.

Etb

In "fixation" thread, Nick says:
"INTRA requires it to work correctly for high i frames. Low bitrate INTRA equals crap Quantisation in real terms on the GH2. Simple as that. (...) Ive been constantly looking at how low I can adjust the bitrate down before the metrics change to shit."

I must agree. After trying i can't have a decent custom L setting lower than the preset. It's linked with the H set of each patch.

So, correct me if am wrong, the more compromised patch between high end user and prosumer (i often switch to one to other, but don't necessary having the time to re-flash the gh2) with AQ4 and GOP1 seems to use (at the moment) quantum4.

Happy end year to everybodyz^^! Seb.

No_SuRReNDeR

I will be using AQuamotion for the feature " True Story" ... I am shooting on a pair of GH2's starting next month...unless something changes...

4 reasons - 1. We have numerous 30MB 16gig Sandisks which I can swap out to log footage
as we go, plus they work well with this patch....
2. 100MB is still REALLY high and GOP1 for motion.
3. They span so I'm not gonna worry if a take runs too long.
4. STABILITY....cant have people on the set losing faith in me as DOP

"In Driftwood I trust"

Heartfelt

@Driftwood Aqua V2 failed on class six. I'd have a ten presently but just bought lenses (doh). Thanks for your work on all of this.

danyyyel

@balazer I can put any value or is it better to put a multiple of 22? Are these setting not relayed between the h and L setting, will it not cause problem if I start to put my own values.

TrackZillas

Hey guy's this video was shot using @driftwood Quantum v2 check it out
Lens pani 20mm f1.7
W.B = Custom
Lighting Tungsten
Profile Cinema

Some of the shots were out to focus.

balazer

@danyyyel, try 60 Mbps for 24L. That's what driftwood had in an earlier version of Quantum. It doesn't need to be a multiple of anything. The reports I saw were that 60 was working, so I'm not sure why he raised it to 100. But I'm sure he had a good reason to raise it.

My understanding is that the H and L settings are independent, but the H setting Nick uses and the frame limit are chosen in concert to give the stream some nice properties and very predictable performance. When you choose a much lower value for L but keep the frame limit corresponding to a higher H, you lose those properties, but it still works and it's still good enough. In fact that's how the stock settings work. Nick may have a different understanding. ;)

Personally, I use Aquamotion v1 with 24L = 66 for the few times I use 24L.

Zaven13

@danyyyel, @johnnyblank,
I personally like SeaQuake, so I kept the H settings at high but reduced the L to 100MBs. As balazer said, if you keep the H settings and just play with the L settings you should be ok. If 100mbs is too high and 60 is too low for L then pick something between 60 - 100 like 80 or 88 and try some test shots. If you like the resolution and storage size then that's your new L number.
Good luck and happy holidays.

sohus

@zaven13
Everyone here is messing with bitrates but these patches are painfully balanced. You can't just reduce the bitrate and expect everything to work fine. I wonder if you guys all run your customized @driftwood settings trough streamanalyzer and see if your settings work. I wouldn't mess with them as I know that Nick tests them thoroughfully. It is not as easy as changing the bitrate... buffers, frame limits all influence stability and quality.

balazer

If you want to mess with bit rates, yes, you should do your own testing. But just because Driftwood has painfully balanced his settings doesn't mean other settings don't also work well. A lot of the time it is as simple as changing the bit rate or frame limit. In fact, I'll give you a nice little recipe: start with Driftwood Reaquainted or Aquamotion v1. Set the 24p frame limit to whatever you want, but not higher than what's in Reaquainted. Set 24H to the frame limit times 24 plus 10 Mbps. That will work to give you intra-frame coding with any bit rate you want from 50 to 150 Mbps.

Zaven13

@sohus
Thanks for your candid comments and concerns. I agree with you that if you change the bit rates and settings you need to fully test. And I have. I have spent hours to test various bit rates and settings under different conditions and different options including fast motion, slow motion, EXTC, different lenses, different SD cards, etc... And yes, I use Streamparser.
Driftwood and others have provided us with a foundation to be able to do our own testing with the understanding of the impact of the setting individually and in relation to each other as also explained above by balazer. I am an IT Architect by trade and systems programmer for many years. Testing has been part of my life.
Cheers.

PaPa

Hey all,

I'm currently using Quantam V2 for 24H but am wondering something about 24L. Because 24L is something around 65 or 66 MBps, and still has a GOP of 1, doesn't that mean that we would basically have a lower quality video than something that runs at 65 or 66 MBps with a GOP of 3?

I'm just looking for something to pair up with my 24H setting that will let me record longer videos and be more space efficient on my cards. And i do understand the difference between motion in the GOP numbers but i figure that the difference between 3 and 1 might be very very very very subtle that at a certain point i would just be motion peeping too hard.

What is a good balance for a lower quality setting that perhaps uses a GOP of 3 to increase the compression but use the same data rate more efficiently?

Muchos appreciation!

balazer

Longer GOPs are more efficient, yes. But you can't have a high and low setting of different GOP lengths in the same firmware. Go long or go 1. There's not much sense in using a GOP length of 3. At 66 Mbps, GOP1 is still pretty darn good looking. I wouldn't worry about it. If you go much lower than 66, that's when GOP1 won't be good quality anymore.

bkmcwd

@soru
I made a test patch new again. :-)
The maximum frame size is set to 1M as well as my usual patch.
Please try.
Although you can also change AQ value for 1080p into 3 from 2, I think that AQ3 is not so practical with 1M max frame size.

UPDATE(2011.Dec.26th):
Second patch is improved version.
It can be spanning with "95MB/s Sandisk Extreme Pro (64GB SDXC)".

NOTE:
In this patch, it is ignored except 24p(24H) as usual.
Please combine with your favorite patch except 1080p.

sohus

@Zaven13 @balazer
My words were not meant for the experts. Just some words of caution that bitrate isn't the only paramater that Driftwood changed. You guys know what you are doing!

driftwood

The only thing you have to watch out for when changing the L setting to a low value is that Quant matrix for INTRA changes to a poorer secondary matrix in which case the low and hi frequencies will experience quite a substantial change. This is why the H setting is high bitrate/highest possible working frame buffer limit and match checked with the buffer analysis that it maintains peak and then QP checked using streameye. Always check your settings 'work' on different scenes and movement. What might look good initially to the eye, used in other scenes could look poor in hi to low frequencies.

PaPa

Hey. on Quantam V2, is it normal that i can't access 60p mode at 720? I tried in both cinema mode and manual movie mode and it's always greyed out.

*edit*
found the culprit. Can't have anything going in through hdmi... very strange.

svart

Ok, so I've been trying like hell to catch up on all these patches and variations. Even though the patch vault explains most of the patches pretty well, I still don't know what Quantum is and why it's any different than any of the others.. Can someone explain this please?

Howdy, Stranger!

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