75Mbps peak bitrate combined with high reliability @ 50/60 fps

At the time the original 75Mbps GH1 Peak Performance Patch was released, I along with many other patch developers had reluctantly concluded that a stable Native 24/25p video mode could not be perfected for the GH1. It was not long after, however, that I discovered new stabilization techniques that led to the development of the Blackout-Powell Native 24p Patch and the Max Latitude Native 24/25p Patch. More recently, with Vitaliy's release of PTool 3.56d, all previously unhackable versions of the GH1 have been liberated for use with freshly upgraded versions of my patches.

The primary focus of recent patches has been the optimization of 1080p Native 24/25p FHD video modes. In order to achieve bitrates as high as 100Mbps, however, it was necessary to restrict the 720p SH video modes to 25p in PAL mode and 30p in NTSC mode. For 720p SH mode recorded at the standard 50/60p frame rates, the 75Mbps peak bitrate of the Peak Performance Patch remains the highest I've achieved. With the aid of new stabilization techniques provided in PTool 3.56d, I have been able to significantly improve the patch's high-bitrate reliability as well. Based on the comparison tests I've conducted, the stability of the updated 75Mbps GH1 Peak Reliability Patch is second only to that of my Reliable In-Camera Playback Patch.

Here are short descriptions of the updated properties of this patch:

75Mbps AVCHD 1280x720 SH mode @ 50/60 fps
While the unhacked 720p50/60 SH video mode offers high frame rates, its low 17Mbps maximum bitrate and long-GOP frame compression hamper its ability to track fast-moving subjects. In 60p mode, this patch reduces the length of each GOP to 20 frames, producing 3 key-frames per second. In addition, the codec's 75Mbps peak bitrate allows it to encode a large amount of image detail into each key-frame. Compression efficiency remains high enough, however, to limit average bitrates to less than 50Mbps.

75Mbps AVCHD Interlaced 1920x1080 FHD mode @ 24/25 fps
For those who do not require Native 24/25p video files, this mode produces the highest quality images available from the GH1 in both 24p and 25p interlaced FHD video modes. Turbo-charged with a 75Mbps maximum bitrate, the codec's ability to track moving objects without producing mud is significantly improved. As with the 75Mbps SH patch, the FHD encoder maintains an average bitrate no higher than 50Mbps.

75Mbps MJPEG 4:2:2 Color 1536x864 HD mode @ 30 fps
The MJPEG Intra-frame codec's unique advantage is its ability to produce highly detailed images in 4:2:2 color depth. This is especially valuable in green-screen rotoscoping, where you want to use the highest chroma resolution available. To maximize its usefulness, I've increased the MJPEG frame size to 1536x864 pixels, while maintaining the camera's normal16:9 aspect ratio. This frame size is exactly 20% taller than SH 720p mode, and 80% as tall as FHD 1080p mode. While it is non-standard, the intermediate frame size allows you to either flexibly crop the edited frame down to 720p, or upsample it to 1080p with minimal loss of resolution. And at 75Mbps max, the MJPEG encoder maintains consistently higher bitrates than the AVCHD encoder, particularly in dimly lit situations.

30Mbps MJPEG 960x720 VGA mode @ 30 fps
This iPod-compatible video mode produces HD-resolution 960x720 videos in a standard 4:3 aspect ratio. Its bitrate averages around 30Mbps.

Overall Patch Considerations
While no GH1 patch can claim to be absolutely bulletproof, I have tested these settings in a wide variety of extreme circumstances. However, with bitrates as high as 75Mbps, the safety margin is inherently narrower than my Reliable In-Camera Playback Patch. This patch is designed and tested only for the fastest Class 10 SDHC cards currently available.

Additional points of interest:

* The 75Mbps Peak Reliability Patch is compatible with all hackable GH1 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 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.

* If shutter speed is set longer than the frame rate (e.g. slower than 1/60 at 60p), low-quality video files may be produced.

* 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 28Mbps in 720p50/60 modes.

* For extended recording times at moderate bitrates, selecting the "L" video mode instead of "SH" will produce bitrates comparable to the camera's unhacked SH video mode.

* While AVCHD bitrates may drop to very low levels in extremely dark situations, this patch should continue to record even in total darkness.

*** WARNING ***

The 75Mbps Peak Reliability 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

75Mbps Peak Reliability Patch Settings File:

This zipped INI file can be used to apply complete patch settings to firmware loaded into PTool 3.56d. 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 "H" button at the bottom of the PTool main window.

Note that with the following PTool Settings File, 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.