GH1 1 GOP experiment

rigs

I have been playing with a 1 GOP - 24p patch that works well for normal detail scenes.
It will crash with static extreme detail and very dark scenes but the cool thing is it will still write a useable file to the card if it does crash.

I am posting this for experimental purposes only, please test it and report back. Perhaps it can be improved upon.

PTool v3.62d (160811) settings

WRAPPER
Native 24p/25p checked

AVCHD COMPRESSION
Video Bitrate FHD/SH = 70000000
Video Bitrate H = 34000000
Video Bitrate L = 34000000
Overall Bitrate = 44000000

AVCHD GOP LENGTH
720p60 GOP size = 1
1080p24 GOP size = 1

PATCHES FOR TESTERS
AVCHD MOVIE MODE

AVCHD COMPRESSION
Preset bitrate = 4400
Preset bitrate 2 = 7000
Overall bitrate 2 = 7000000

AVCHD Research
Constant for 1080p = 7000600
Constant for 720p = 4405600
Frame related comparison = 24
Video buffer = 50.000.000

LucasAdamson

Surely GOP 1 defeats the whole design ethos of AVCHD, and renders it's clever-compression advantages redundant!

rigs

@ LucasAdamson I'm in search of better quality not to concerned about compression advantages. I think GOP 1 offers better low light detail.

Stray

Edit : oops don't post when tired. Just realised this was a GH1 setting.

stoney

@rigs you'd need to double the bitrate just to match I-frame size of the 44Mbps 12GOP. GOP3 or 6 seems better compromise than GOP1.

CRFilms

The problem with the old thread, it seems to be primarily GH2 focused. I remember reading in the early days of the GH2 hack, that the encoding was different and GH1 settings wouldn't work on the GH2. Do the same hacks and settings apply to the GH1? If not there definitely should be a GH1 specific low GOP topic.

This is the only other place I've found any info on low GOP settings: http://www.asterdesign.com/en/gh1-lumix-gh1-hack-settings

LPowell

After pixel-peeping MJPEG, short-GOP AVCHD, and AVC-Intra videos, my conclusion was that for 1080p, intra-frame codecs need 100Mbps or more to handle the finest details. That's problematic with the GH1, not because of the sensor or codec, but due to the limited write-speed of the camera's SD-card controller. The GH2 is a far more robust candidate for short-GOP AVCHD encoding.

rigs

Thanks CRFilms thats a very comprehensive link on GH1 hacks. I feel there are some definate advantages to the lower gops in relation to motion and shadow detail. I think allot of the problems still come up with native 24p causing some issues and adding to a non stable patch. I hope some of you GH1 users can join in this quest to try and make it better.

CRFilms

@LPowell I've looked at all your patches and the 1080p GOP is around 12-15(can't remember exactly) right? Can we just change the GOP down or do other settings have to change as well on the max latitude patch? I'll grant you, GOP1 may be a bit much, especially for the GH1, but I would defenitely like to play around with GOP3-6 to see what it looks like. And even if low GOP isn't better than max bitrate, it's all about personal aesthetic preference and what's worse can sometimes look better.

LPowell

@CRFilms - "Can we just change the GOP down or do other settings have to change as well on the max latitude patch?"

No, it's not that simple, the reliability of these GH1 high-bitrate patches is very sensitive to GOP-length and is rather challenging to test. I had to run statistical tests using multiple takes of codec-breaking scenes to determine which combination of settings was most resistant to failure across a range of stressful shooting conditions.

driftwood

Likewise for GH2 :-)

rigs

@ driftwood I see you have GOP 1 working with the GH2. I know the codecs are different animals and the GH2 does have more processing power, but it seems to be working somewhat in my tests. I think the crashs which ocur as usual on static high detail scenes might have to do with 24p being recorded as 23.971 not at 23.976 this has been a problem from day one. So many variables can fall into beyond the SD card controller not being up to snuff.

driftwood

@rigs Its bleedin amazing... just gotta try and squeeze some more detail out of it... but Im working on 50p/60p and 1080i for GOP 1 right now. And just trying to get past 20 seconds on the various death charts at 720p is a f@ckin helluva game. Gawd knows what u tried on the GH1!

rigs

@ driftwood someonetimes these patches are as much fun as a fork in the eyeball. I have worked on over a thousnad variations of 24p since the GH1 hack came out. The GH2 ptool seems to have better for options and I'm using a 66mbit 3 gop version right now that looks pretty good. Were Just jumping back into some pick up scenes for a week on a project we did in June with 2 GH1's and a GH2. I will give your 1GOP a go on some scout shots and see how it goes. In the mean time my GH1's will handle the grunt of the action all be it at my current 6 gop 24p patch.

CRFilms

Finally got around to play with a GOP1 patch....and interesting. The footage I shot wasn't particularly noteworthy but the stream parser does show some interesting bit rates. Capture one is on the left, two in the middle and three on the right:

Capture 2 is where I played with a Gop setting of 2 and it didn't look good. All the settings were the same as the GOP1, so I figured lets just change it to 2 and....don't even know what happened there.

Capture 3 is....am I seeing that right? Did I hit a peak 300 mbs a few times?!? This is with a Transcend Class 10 16gb card. This was very low light, super under exposed mostly, and a pancake 14mm 2.5, iso 200. I'll take it outside now and try and get some decent footage. Only crashed shooting super dark scenes. Near blackness and low GOP don't mix.

rigs

I have been having some good luck with this patch it gives you smooth cadence with pans and any fast moving scenes. It averages around 45 -65 Mbps on well lit and exterior high detail scenes.

For most of the scenes I have filmed, it was 97% stable and produced some of the best 24p highest quality I have ever seen coming out to the GH13 to date. I have found that If do get a card write error on high detailed scenes, it will still save the clip file and resume back to live view mode in a few seconds once the clip has been forced to stop recording. Unlike other patches that lock up the camera completely and require you to pull the battery and power it up again with the locked up clip being completely lost.

So far the best camera and lens scenario for this patch has been with non Lumix lenses. I have used several Canon FD lenses ranging from f1.8 - f22 with good ND filters with my tests. It is also advisable to shoot 1/3rd of a stop under exposed and to use a SanDisk Extreme Pro 30Mbps card to help safeguard you with the best possible write error protection.

rigs

Here is may latest GOP 1with some tweaks. Please give it a try

CRFilms

@rigs ....The problem with the GOP1 patch is...over exposed it won't record, and it dies fast in low light. Didn't think that would be that big of a problem, but even a few seconds of pure black and it shuts down and locks up without saving. I tried the new one and same thing and I don't want to have to buy the top of the line card to record.

I adjusted Lpowells Max Latitude 100mb at GOP 15 to GOP6 and it went a lot better. I'll try that for a while now and see how that goes.

rigs

You must use SanDisk Extreme Pro 30Mbps cards for this patch.

spamrakuen

What about 720p? It's stable?

Thanks for your work, rigs.

rigs

Sorry I have not tested 720p

rigs

Made some changes to the patch with better luck

PTool v3.62d (160811) settings

WRAPPER
Native 24p/25p checked

AVCHD COMPRESSION
Video Bitrate FHD/SH = 65000000
Video Bitrate H = not checked
Video Bitrate L = not checked
Overall Bitrate = not checked

AVCHD GOP LENGTH
720p60 GOP size = 1
1080p24 GOP size = 1

PATCHES FOR TESTERS
AVCHD MOVIE MODE

AVCHD COMPRESSION
Preset bitrate = 530
Preset bitrate 2 = 1060
Overall bitrate 2 = not checked

AVCHD Research
Video buffer = 25.000.000

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