UPDATE: This MJPEG patch is compatible with the latest version of PTool 3.65d. The standard non-anamorphic version is also included in Flow Motion v2, which is available for download here:

http://www.personal-view.com./talks/discussion/3337/gh2-flow-motion-v2.02-720p-reliability-in-auto-exposure-modes/p1

As numerous GH2 owners have discovered, Vitaliy's recent updates to PTool have enabled the newly hacked GH2 to sustain remarkably high bitrates in MJPEG HD mode. What's even more impressive is that the GH2 maintains error-free recording stability at bitrates significantly exceeding those that can be used reliably on the GH1. And where the GH1 struggled to produce FHD-size videos in MJPEG mode, the GH2 can be readily patched to record in any MJPEG frame size, all the way up to 1920x1080p.

The MJPEG encoder's most valuable asset has always been its ability to record each video frame as a JPEG-encoded key frame. This enables it to track high-speed action at 30fps without any of the smeared motion artifacts that plague low-bitrate AVCHD videos. To produce high-quality, detailed key frames at 1080p, however, an Intra-frame encoder must work at higher average bitrates than the GH1 was able to sustain. With PTool's support of the GH2, it is now possible to use MJPEG HD mode to produce reliable 1080p videos at an average bitrate of 100Mbps in sharply-focused, highly-detailed scenes.

The MJPEG encoder also excels in difficult low-light conditions where the AVCHD encoder cuts down its bitrate to minimum quality levels. On the GH1, MJPEG HD mode could be relied on to produce bitrates over 24Mbps even in dimly-lit scenes. With patch settings optimized for consistent bitrate production, the GH2 can maintain high bitrates of up to 100Mbps across the entire exposure range, producing high-quality images under any and all illumination levels. Combined with the GH2's low-noise image sensor, MJPEG HD mode can render clean, gradable images in conditions that the GH1 would have found hopelessly underexposed.

MJPEG image quality with exposure bracketing

Below are 100% crops of two series of four bracketed exposures I took in MJPEG HD mode, patched to 1920x1080 resolution. For each shot, I set up the GH2 on a tripod with a fixed aperture at ISO160, and varied the shutter speed from 1/60 to 1/500 second, producing videos bracketed at one-stop exposure steps. Frame grabs were then composited in Photoshop and saved at maximum JPEG image quality. These scenes were selected as typical outdoor subjects shot in natural lighting, as opposed to shots of extremely detailed foliage. The GH2 exhibited no reliability issues whatsoever, and recorded all videos at impressively consistent bitrates of around 90Mbps.

iPad compatible MJPEG VGA video mode

In addition to MJPEG HD mode, recent versions of PTool have provided patches for adjusting the frame size and image quality of MJPEG VGA mode as well. Unlike the HD 16:9 aspect ratio of HD mode, VGA video mode records with an SD aspect ratio of 4:3. I've optimized VGA mode to produce 960x720 videos at consistent average bitrates of about 30Mbps. These videos are compatible with the maximum-quality download specifications of the Apple iPad, with its 1024x768 screen resolution.

GH2 Patch Considerations

Patches for the GH2 are currently in active development by numerous testers, and Vitaliy has updated PTool several times with exciting new features. The patches in the downloadable PTool INI settings file below have been systematically tested using PTool version 3.61d and have produced no reliability issues to date. This patch is designed and tested only for the fastest Class 10 SDHC cards currently available.

Additional points of interest:

* The 100Mbps GH2 Low Light MJPEG 1080p Patch is compatible with all GH2 cameras, and is switchable between NTSC and PAL modes.

* 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 sharply-focused, highly-detailed subject matter. Average scenes will produce average bitrates.

* High bitrate MJPEG videos may not play back reliably in-camera or on low-powered computers.

* 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.

*** WARNING ***

The 100Mbps GH2 Low Light MJPEG 1080p 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 PTool release is to download it directly from the following link:

Download PTool here: https://www.personal-view.com/faqs/gh2-hack/ptool-software

100Mbps GH2 Low Light MJPEG 1080p Patch Settings File:

For use with PTool v3.62d and above, I've prepared anamorphic as well as standard aspect ratio settings files:

* For use with standard lenses, the standard patch will produce two types of MJPEG 30p videos:

HD mode: 1920x1080 HD videos, with peak bitrates up to 100Mbps.
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 for 1.33X anamorphic adapters, with peak bitrates of 100Mbps.
VGA mode: 2160x810 videos for 2X anamorphic adapters, with peak bitrates of 100Mbps.

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 GH2 v1.0. The settings contained in the INI file will automatically be installed in the "C" 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 GH2 v1.0 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.