100Mbps Max Latitude Native 24/25p Patch

L

Lpowell

Veteran
UPDATED to Version 2! INI files for the latest version of PTool ready for download

As you've no doubt heard, PTool 3.55d and higher have liberated all previously unhackable versions of the GH1. In addition, PTool provides a variety of new patches that I've been able to incorporate into the 100Mbps Max Latitude Native 24/25p Patch, making it more versatile than ever.

To make use of these new features, download the latest version of PTool from the following link:

http://www.gh1-hack.info/ptool3d.zip

Version 2 of the 100Mbps Max Latitude Native 24/25p Patch supports the following new features:

* Works on all Panasonic GH1 cameras, both hacked and unhacked.

* Expanded video and audio buffers to guard against recording failures at high bitrates.

* 15-frame GOP-size in both PAL Native 25p and NTSC Native 24p video modes.

* Standard patch: 30Mbps iPad-compatible VGA MJPEG mode records in 960x720 resolution.

* Anamorphic patch: 65Mbps 2X anamorphic VGA MJPEG mode records in 1920x720 resolution.

100Mbps Max Latitude Native 24/25p Patch Settings Files

These zipped INI files can be used to apply complete patch settings to firmware loaded into PTool 3.55d. To use, unzip the INI file into the same folder as the PTool application. Launch PTool and load the firmware for GH1 v1.32. The settings contained in the INI file will automatically be installed in the "A" button at the bottom of the PTool main window.

Note that with the following PTool Settings Files, you may at any time re-install the original Panasonic GH1 v1.32 firmware into the camera. You may also copy each type of patched or original firmware to separate SD cards, and use them to quickly switch between patches as often as you like.

View attachment LPowell - 100Mbps Max Latitude Native 24-25p Standard Patch v2.zip

View attachment LPowell - 100Mbps Max Latitude Native 24-25p Anamorphic Patch v2.zip

Read on for updated background information on these patches:

Yet another Native 24p... no wait, a 25p patch?

While response to the recently published Blackout-Powell Native 24p Patch has been quite positive on the NTSC side of the world, PAL users have found some issues in Native 25p mode. The Native 24p GOP size of 12 proved to be a bit optimistic for Native 25p, and further testing showed that a GOP size of 15 produced more reliable results in PAL FHD mode. Even with this modification, PAL Native 25p still did not perform as well as the NTSC Native 24p mode the patch was originally designed to optimize. This prompted me to take a closer look at how PAL mode works on the GH1, with the goal of finding a better way to optimize it for Native 25p use.

Unlike the GH1 NTSC 1080p mode, PAL 1080p videos are not burdened with 3:2 pulldown. They are recorded in a 25psF video stream, with each progressive frame split into a pair of 50i fields. While de-interlacing this stream into progressive 25p video is easily done, AVCHD compression tends to produce better results when applied to native progressive frames. In addition, the absence of a true 25p video mode on the PAL GH2 highlights the worth of optimizing the GH1 specifically for Native 25p applications.

Why so many patches, dude?

The most significant performance limitation of the Blackout-Powell Native 24p Patch is its 55Mbps peak bitrate limit. This imposes a conservative maximum bitrate on FHD and SH video recordings compared to my interlaced 75Mbps GH1 Peak Performance Patch. As a result, the Blackout-Powell patch works reliably on Class 6 and higher SD cards, while the 75Mbps bitrate of the Peak Performance Patch requires Class 10 cards. Regardless of its moderate peak bitrate, however, the Blackout-Powell patch maintains a consistently high average bitrate, making it well-suited for controlled lighting video shoots. But what if there was yet some way to combine a high peak bitrate with Native 24p mode?

Breakthrough!

Back when I was convinced that Native 24p was hopeless, the first clue that extremely high bitrates might pave the way to a stable patch came from research done by cbrandin, the author of the invaluable GH1 StreamParser. Here's what he discovered:

cbrandin said:
Possible breakthrough on Native 24p!

I've been digging into the GH1 firmware code and found that overall bitrate appears to have a big effect on the maximum speed that flash memory writes can occur. I’ve always wondered why the write speed error comes up in AVCHD mode when clearly the data rates are well below what the card can handle. I think I found the answer...

When the write speed error comes up it’s because the calculated maximum write rate has been exceeded – whether the card can handle more or not. I tried the LPowell settings but changed two things: I doubled the overall bitrate to 86,000,000 and I checked Native 24p. It appears to be working!
Click to expand...
Sadly enough, I was the one who shot down this hope at the time, as I found insidious empty frames lurking in the Native 24p bitstream. It was only recently that I discovered how to banish this flaw in the Blackout-Powell Native 24p Patch. With that problem solved, I decided to give cbrandin's high bitrate inspiration another chance...

100Mbps?!!

OK, enough bait-dangling. Of course you already know it must work, otherwise I wouldn't be posting this thread. There's one significant catch, however, similar to another patch of mine, the 50Mbps Fast Action 3-Frame GOP Patch. With that patch, I discovered a way to produce stable SH mode 720p videos with a remarkably short 3-frame GOP size. To do so, I cut the SH mode NTSC frame rate down from 60fps to 30fps (and the PAL frame rate down from 50fps to 25fps). Cutting the frame rate in half reduced the bitrate as well, allowing me to pack the video stream with up to 10 key frames per second. That made the patch very adept at tracking quickly moving objects, but constrained it to a 55Mbps peak bitrate.

Acting on cbrandin's high overall bitrate suggestion, I found that setting the peak Native 24p bitrate to 100Mbps could indeed work, but only at the price of totally demolishing SH 720p60 mode. As a result, I was forced to patch SH mode down to 30fps, and determined that it also needed a 5-frame GOP size. However, the resulting 720p30 mode produces utterly reliable videos with average bitrates up to 50Mbps and peak bitrates over 100Mbps. The corresponding 720p25 PAL mode is just as impressive, with a comparable 100Mbps peak bitrate and average bitrates up to 40Mbps.

FHD mode, however, is where this patch shreds all others. With a maximum bitrate of 100Mbps, highly detailed key frames can be encoded with minimal compression loss. This significantly improves the quality of underexposed areas that would be reduced to mud at a lower bitrate. The result is a perceptible increase in AVCHD latitude, enabling you to shoot at lower exposure levels and capture a broader range of image details.

Here's an example of a field of dandelions shot in direct sunlight, with the center section cropped out. The frame in the upper left corner was shot at f8 in order to preserve highlight detail. A plot of its green channel spectrogram is displayed below it, and shows that most of its energy content is below 50% exposure. In the upper right corner is a frame from a second take, shot at f5.6 to capture more shadow detail at the expense of blowing out the highlights. Its spectrogram shows that while its exposure levels are centered around 50%, it contains an excessive amount of clipped overexposure.

dandeliongamma720.jpg


The center image is a copy of the left image, with its gamma curve adjusted to bring its average exposure levels up to match the right image. Notice, however, that I've managed to increase contrast and bring up the shadow detail without blowing out the highlights. The original FHD video had an average bitrate of only 33Mbps, but with a peak bitrate of 80Mbps, the encoder was able to pack up to 7.5Mbits into each key frame. This is what maximum latitude gives you the ability to do.

OK, but is it reliable?

In the course of testing the 100Mbps Max Latitude Patch, I shot many comparison tests of codec-breaking foliage, comparing its 1080p reliability to both the Blackout-Powell Native 24p Patch and the interlaced Peak Performance Patch. In case after case, I found that the PAL Native 25p FHD mode in the Max Latitude Patch could handle intensely dense scenery that would cause one or more of the other patches to fail. An advantage of the PAL Native 25p mode is that its average bitrate stays around 40Mbps, with a peak bitrate of up to 100Mbps. The average bitrate of the corresponding NTSC Native 24p mode can exceed 50Mbps, which appears to make it noticeably less robust than the PAL Native 25p mode.

In all cases of recording failures, I found a practical workaround that enabled me to complete the shot. Simply reducing exposure levels by 1/3 to 1/2 stop lowered the bitrate enough to confidently record the scene. And with the increased shadow detail latitude provided by the patch, I could do this with little risk of underexposure. Here's an example where I was able to shoot a deer in the shadow of a bush, without blowing out the highlights on the sunlit foliage:



100Mbps Max Latitude Native 24/25p Patch Settings Files:

For the Max Latitude Patch, I've prepared a choice of two INI settings files that differ only in the settings for the MJPEG 30p modes:

* For use with standard lenses, the standard patch will produce two types of MJPEG videos:

HD mode: 1280x720 HD videos in 4:2:2 color depth, with peak bitrates up to around 60Mbps.
VGA mode: 960x720 iPad-compatible videos, with peak bitrates up to 30Mbps.

* For use with anamorphic lenses, the anamorphic patch supports two different squeeze ratios:

HD mode: 1920x810 videos optimized for 1.33X anamorphic adapters, with peak bitrates up to around 75Mbps.
VGA mode: 1920x720 videos optimized for 2X anamorphic adapters, with peak bitrates up to around 65Mbps.

Practical use of anamorphic lenses on the GH1 is discussed in detail in the following thread:
Anamorphic Cinemascope in Native 1920x810 MJPEG Mode

*** WARNING ***

The 100Mbps Max Latitude Native 24/25p Patch will not work properly with previous versions of PTool. My thanks once again go to Vitaliy Kiselev, for his pioneering work on PTool, and to cbrandin for his invaluable Stream Parser tool.

The best way to insure that you have the latest version of PTool is to download it directly from the following link:

Download PTool here: http://www.gh1-hack.info/ptool3d.zip


These zipped INI files can be used to apply complete patch settings to firmware loaded into PTool. To use, unzip the INI file into the same folder as the PTool application. Launch PTool and load the firmware for GH1 v1.32. The settings contained in the INI file will automatically be installed in the "A" button at the bottom of the PTool main window.

Note that with the following PTool Settings Files, you may at any time re-install the original Panasonic GH1 v1.32 firmware into the camera. You may also copy each type of patched or original firmware to separate SD cards, and use them to quickly switch between patches as often as you like.

View attachment LPowell - 100Mbps Max Latitude Native 24-25p Standard Patch v2.zip

View attachment LPowell - 100Mbps Max Latitude Native 24-25p Anamorphic Patch v2.zip
 
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Aside from dense foliage, one of the more challenging subjects for the AVCHD encoder is handling the wide dynamic range of a shaded outdoor scene under blue skies in broad daylight. With a low bitrate patch, capturing clean shadow detail will often require you to overexpose the sky and may even turn it completely white. With careful adjustment of exposure, the 100Mbps peak bitrate of the Max Latitude Patch can encode both the subtle highlight gradients of a partly cloudy sky as well as shaded foliage details beneath a grove of trees:



Spikey conifer branches can be a particularly challenging subject for the AVCHD encoder due to the innumerable sharp straight edges of their boughs. I shot a series of tests on a pine tree that was so dense with foliage that Vimeo's re-encoded FHD videos were unable to display the tree without visibly smearing the details in its branches. To appreciate the level of detail in these videos, there's no substitute for downloading the original MTS files. This particular test highlighted the reliability of the PAL Native 25p mode in the Max Latitude Patch as it was the only 1080p patch able to consistently record extended video takes without fail. The longest take I was able to record with the Blackout-Powell Patch was about 6 seconds. And while the Peak Performance Patch failed in only about half of my attempts, it's limited to recording FHD video in interlaced 1080i50 format.

Note: These shots were intentionally overexposed in order to stress the encoder with higher birates than a properly exposed shot would require. In practice, I would have shot this pine tree at an exposure at least a full stop lower.

Pine Tree via 100Mbps Max Latitude Native 24/25p Patch:


Pine Tree via Blackout-Powell Native 24p Patch:


Pine Tree via 75Mbps Peak Performance Patch:

Additional Points of Interest

* The 100Mbps Max Latitude Native 24/25p Patch is compatible with all hackable GH1 cameras, and is switchable between NTSC and PAL modes.

* This patch was designed and tested to work only with high-speed Class 10 SD cards and higher. While Class 6 cards may be used to record at low bitrates, I have definitely seen them fail in extreme cases.

* I recommend using the camera to format your SD card at the start of each shoot, to guard against SD card memory fragmentation.

* Peak bitrates are obtained only with well-lit, sharply-focused, highly-detailed subject matter. Average scenes will produce average bitrates.

* High bitrate AVCHD videos may not play back reliably in-camera. The MJPEG videos produced by this patch will not be playable in-camera.

* AVCHD 4GB file-spanning for long video takes may not work reliably at high bitrates. For reliable recording of takes longer than about 12 minutes, I recommend selecting the "H" video mode instead of "SH". This will produce average bitrates of about 24Mbps in 720p25/30 modes.

* For extended recording times at moderate bitrates, selecting the "L" video mode instead of "SH" will produce bitrates below 17Mbps.

* If shutter speed is set longer than the frame rate (e.g. slower than 1/30 at 30p), low-quality video files may be produced.

* While AVCHD bitrates may drop to very low levels in extremely dark situations, the 1080p FHD modes should continue to record even in total darkness. 720p SH modes may stop recording if subjected to darkness for over 10 seconds at a time.
 
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Thanks Ipowell. In FHD this patch still locks up on the high contrast sharp detail foliage.
Extreme 16 gb 30MB card, camera NTSC - AVCHD FHD f6 -1/3rd, 1/50 iso 100, manual movie mode. 14-140 kit lens, tripod mounted locked off shot
 
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Yes, I've found NTSC Native 24p mode significantly less robust than the PAL Native 25p mode. Try reducing exposure a bit and see if that allows you to complete the shot.
 
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I do have to admit that this is cool. I have my fairly happy gh13 sitting here and may have to test it. Then put it up against the GH2 and pixel peep.
 
Hey lpowell, great work. I'm a 5D shooter but I've been keeping an eye on GH/GF developments and I just picked up a GF1 to use as a b-cam for an upcoming feature. I have a few Iscorama 1.5x and 1.7x anamorphics. I've read through many of the threads but I could use some advice. I'd like to shoot 24/25p, reasonably high bit-rate m-jpeg, 4:2:2 if possible. The feature will be delivered in a 1920x720 2.66:1 aspect ratio with mixed anamorphic and cropped 1080p 5D footage. What hacks would you suggest? 720p capture will be fine with my Iscorama's but I'd like the option of shooting some non anamorphic 1080p. I need something reliable.
 
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Wow, thanks LPowell again, aside from whether this patch can top my joy with your other patches (most recently the "sexy 25p version") the info you provide about the workings of the codec and how the different parameters relate are very useful indeed... then bringing it all back to the real-world situation of getting the most dynamic range, great work!

So if I understand, the difference with the former 25p with 15-GOP is that by tuning down the SH mode to 30fps, you win out with more stability and higher ceiling for the FHD bit-rate, correct?

greetings, ninetto
 
ninetto said:
So if I understand, the difference with the former 25p with 15-GOP is that by tuning down the SH mode to 30fps, you win out with more stability and higher ceiling for the FHD bit-rate, correct?
Click to expand...
Yes, for the Max Latitude Patch I developed a new stabilization technique that delivers up to twice the peak bitrate of the Blackout-Powell Patch, at the cost of losing the 50/60p SH video mode. While the reliability of the NTSC Native 24p FHD mode is about the same in both patches, the PAL Native 25p FHD mode in the Max Latitude Patch is significantly more robust.
 
Lpowell, if you were a girl, I'd stalk you. Got two sd cards, each loaded with the 24p blackout-lpowel and 75mb peak performance patches respectively. They both leave viewers slack-jawed, but it's been driving me crazy that I can't shoot anything in mottled sunlight. Let's just see about that now.... TFYGA (thanksforyourgeniusagain).
 
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Hi Again greatful of you delivering these patches.
I can report after trying this patch today that FHD breaks up with mud all over the place using faster shutter speeds with both slow and fast pans (I had shutter over 100 to see how robust)...I went back to my old settings and FHD is mud free when using high shutter speeds.
 
Hi Mr P,

I hacked my GH!£ (as I like to call it, shift all the way) and my Kowa 2x fits snugly inside my fd 50mm 1.4 so I just taped it on with insulation tape!

It works well though. I've tried the Mpeg but I too get the white line on the bottom and the resolution is pretty dull at 540 IMHO. The AVCHD though is amazing. Vegas spews out 3840x1080 and it looks mint, quicktime player starts full size and it's huge and lovely, very filmic, and that's only on the reliable patch which only failed on a fountain after a minute maybe.

I've loaded the badboy patch and have an extreme 30mb/s to play about with. I can't describe how amazing it is having what to me seems like a pocket movie camera, the anamorphic seems to give it a dreamy feel, slightly less crisp but in a good way in my opinion, less like broadcast, more like movie.

I'll try shooting 'bushes of death' 2mo. I'd be happy making my movie with reliable so am intrigued to see the difference. Is it still the case that certain patches are better for certain things? That would make a great sticky.

I'm gonna stick with the FHD and stretch in post as I can't see anything dodgy and I think the extra resolution looks better. I don't know if any film festivals could handle the 2538x1080 rather than the 1920x810 mind. Is it wasted resolution? If it is I could tape a tiny bit top and bottom for deshaking I thought and crop. I really like the supercinemascope. I'm gonna have to tape off the screen though as I keep framing for supercinemascope and not cinemascope though.

I shall report back from PALland 2mo.

Thanks again Mr P
 
lpowell, will in your opinion unchecking Native 24/25p increase stability in this very patch? That Native 25p option isn't a big deal in the PAL world, I don't need it much and it's known to cause troubles. I'm going to try it anyway but perhaps your personal testings have revealed some real-life statistics. That would be good to know beforehand.
 
zigizigi said:
lpowell, will in your opinion unchecking Native 24/25p increase stability in this very patch?
Click to expand...
Good question, zigizigi! The patch does in fact work without Native 24/25p checked, and produces comparable bitrates. My initial tests didn't show any clearcut benefits to recording in interlaced mode, and I assumed people would naturally prefer Native 24/25p. However, more thorough testing might well reveal an improvement in reliability, if not in PAL FHD mode, perhaps with interlaced NTSC FHD recordings.
 
Thx Lpowell for your hard work. I just filmed grass and trees with reducing exposure levels by 1/3 so with ntsc it crashed after few seconds and using pal it crashed after about a minute. Now i probably will go back to the "40Mbps AVCHD High Reliability Patch" since that's the only one that never crashes but at the same time i wanna test this one a lil more cause i'm kinda tired of the pulldown removal step cause it takes alotta time and after i do it the mov files are way bigger than the mts.

Don't know if i understood right but is this patch performing better in low light than "40Mbps AVCHD High Reliability Patch" ? Knowing that in low light i always use Emory's Setting to reduce FPN.
 
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