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    100Mbps GH2 Low Light MJPEG 1080p Patch
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    Update for PTool 3.62d, with support for anamorphic MJPEG videos at up to 2160x1080p!

    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.

    Mausoleum Bracket.jpgMonument Bracket.jpg

    The original MJPEG MOV files can be downloaded from my Vimeo site:

    http://vimeo.com/26836032
    http://vimeo.com/26836635
    http://vimeo.com/26837185
    http://vimeo.com/26838644

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

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

    For use with PTool v3.62d, I've prepared a choice of two INI settings files that differ in the settings for the MJPEG 30p modes:

    * 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 optimized for 1.33X anamorphic adapters, with peak bitrates of 100Mbps.
    VGA mode: 2160x810 videos optimized for 2X anamorphic adapters, with peak bitrates of 100Mbps.

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

    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.
    Attached Files Attached Files


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    #2
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    Reserved for video samples.


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    #3
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    Wow that was fast, lpowell. Most impressive.

    Is it crashing at all @ 100mbps?
    When you say "This patch is designed and tested only for the fastest Class 10 SDHC cards currently available": are you talking 30MB/s and/or 45?


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    Is "1080p MJPEG" upressed 720p like in GH1 or is it proper 1080p on GH2? Thanx.


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    Senior Member Mj882's Avatar
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    Lovely work lpowell, will be downloading it soon.

    Is Transcend 16GB Class 10 SDHC card fine for this patch?
    "Cinema is the most beautiful fraud in the world." - Jean-Luc Godard


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    I've seen no crashes at all with Class 10 SD cards on the 100Mbps GH2 Low Light MJPEG 1080p Patch.

    The actual resolution that Panasonic's cameras are capable of optically resolving at 1080p has been debated in numerous threads, regarding not only the GH1 and GH2, but the AF100 as well. The samples and figures I've studied showed a resolution of around 750 lines in 1080p mode, which is fairly typical of the current generation of camcorders. In addition to the raw image resolution of the camera, MJPEG and AVCHD introduce encoding artifacts that further reduce the actual resolution produced. While high-bitrate patches cannot improve the resolution of the image sensor, they can greatly reduce the amount of degradation from compression.

    As to whether the MJPEG 1920x1080 frame sizes are literally upscaled from a 1280x720 frame, I have seen no tangible evidence that this is in fact the case. Scaling of that sort should produce telltale irregularities in fine diagonal lines, and I've yet to see a sample image that demonstrates this artifact. The sample frames I included contain numerous fine details that expose the limits of MJPEG 1080p resolution. To my eyes, they appear to be directly captured from the image sensor rather than upscaled.


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    Senior Member Mj882's Avatar
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    If I record 1080/24p and have the shutter at 50 - will that produce low quality video files? I'm looking to use the shutter speed that will give me the most filmic results with 24p.
    "Cinema is the most beautiful fraud in the world." - Jean-Luc Godard


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    The 100Mbps GH2 Low Light MJPEG 1080p Patch records only at 30fps on both PAL and NTSC cameras. Any shutter speed 1/30 second or faster should produce high quality results.


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    Mj882
    Honestly, it's going to be hard to spot the difference between 24 and 30p, especially if you are posting on the internet.
    You could always add a film-look plugin, like Magic Bullet.


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    Senior Member Mj882's Avatar
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    Really? Not sure if it's me, but 30p doesn't seem to have the organic look that 24p (25p) depict.
    "Cinema is the most beautiful fraud in the world." - Jean-Luc Godard


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