GH2 Flow Motion v2.02

• Reliable 100Mbps peak performance in AVCHD 24H, HBR, FSH, SH, and MJPEG HD.

• Exclusive 140Mbps turbo mode boosts peak bitrate to handle 80% Slow-Motion 24H mode.

• Records reliably with Class 10 30MB/s cards, with 60Mbps file-spanning in 24L, FH, and H modes.

• 95MB/sec SD cards support file-spanning in all video modes (except NTSC HBR 30p and FSH 60i).

• Full support for all NTSC and PAL video modes and options, including ETC zoom mode.

• In-camera playback of all AVCHD video files. (MJPEG HD videos not playable in-camera.)

• Failsafe operation with any lens, in any video mode, under any type of shooting conditions.

• Consumer-friendly auto-exposure features fully supported in 60Mbps 24L, FH, and H modes.

• Fast Action 3-Frame GOP performance with B-frames visibly indistinguishable from I-frames.

• Optimal motion picture quality consistently maintained in underexposed low-light conditions.

Flow Motion v2 is the culmination of over three months of investigation into the core encoding parameters of the Panasonic GH2 AVCHD encoder. The goal of this project has been to produce a unified patch that combines failsafe reliability with consistent, high quality performance across the entire range of video modes and options provided by the GH2. These criteria include not only still-frame image quality, but frame-to-frame motion picture continuity as well, evaluated perceptually at 24, 25, 30, 50, and 60 frames per second. Rather than simply maximizing the encoder's peak bitrate, Flow Motion v2 is fine-tuned to produce optimal motion picture quality with minimal degradation from undesirable aliasing and digitizing artifacts. The result is an unmistakable improvement in video quality with no significant drawbacks, using Class 10 30MB/sec SD cards and virtually any lens compatible with the GH2.

Functional Limitations of Stock GH2 Video Firmware

Although it offers a wide variety of video modes and options, the GH2's stock firmware is restricted in both functionality and video bitrate. Thanks to the dedication of Vitaliy Kiselev, many of these limitations can be overcome through the custom firmware settings provided by PTool v3.65d. Flow Motion v2 is an integrated set of patches that enable the following extended features:

• Selection among all supported interface languages.

• Access to both PAL 25/50p and NTSC 30/60p frame rates.

• Extended low-light exposure settings up to ISO 12800.

• Removal of 30-minute recording restrictions in EU locales.

• Enlargement of MJPEG videos to 1080p FHD frame size.

• Pasadena Pulse Audio Patch V2 B2, thanks to Per Lichtman.

Image Quality Shortcomings of Stock GH2 Video Firmware

The GH2's stock firmware limits its AVCHD encoder to a peak bitrate of 24Mbps in 24H and HBR modes, and to 17Mbps in FSH and SH modes. In addition, it uses long-GOP recording sequences of 12-30 frames that produce only about two keyframes (I-frames) per second. Flow Motion v2 boosts the AVCHD encoder's peak bitrate to 100Mbps in all video modes and uses a short 3-frame GOP in all 1080p video modes (and a 6-frame GOP in 720p modes), that produce 8-10 keyframes per second. These improvements enable Flow Motion v2 to capture highly detailed, fast moving images with far more fidelity than the stock firmware's restricted bandwidth can accommodate.

At a deeper level of operation, the GH2's AVCHD encoder uses built-in Quantization Tables designed to compress the video data as efficiently and compactly as possible. When shooting highly detailed subjects, quantization often produces undesirable rectangular artifacts ("macroblocking") which are then filtered by built-in Deblocking Tables. Unfortunately, the tables used by the stock GH2 firmware sacrifice image quality in favor of compression efficiency, producing consumer-grade results. In a further reduction of image quality, highly compressed P and B-frames are encoded with coarser quantization tables than I-frames, degrading frame-to-frame consistency within each GOP.

Flow Motion v2 replaces the GH2's Quantization and Deblocking Tables with custom matrices, hand-tuned for each video mode, that are crafted to minimize macroblocking and digitization artifacts. This enables the encoder to make full use of its available bitrate to encode genuine image details rather than wasting bits attempting to correct macroblock encoding flaws. In addition, Flow Motion v2 applies equal levels of quantization to all types of frames, producing P and B-frames that are visually indistinguishable from I-frames.

Below is an example of the digitization artifacts produced by the GH2's stock firmware, compared to results produced by Flow Motion v2. On the top is a 200% crop of a 24H mode frame grab from the unhacked GH2 AVCHD encoder. You can clearly see jagged macroblock encoding artifacts due to the stock firmware's inadequate bitrate. Below it is the same stream of water shot with Flow Motion v2 in 24H mode:

Support for GH2 Auto-Exposure Features

Flow Motion v2 works reliably with the GH2's consumer-friendly auto-exposure features in both 24p and HBR video modes. However, in 720p SH video mode, auto-exposure operation may cause recordings to fail sporatically and the camera may need to be restarted. To avoid this pitfall, I recommend using Flow Motion's 60Mbps 1080i FH and 720p H video modes when using any combination of the following features:

• P, A, or S exposure modes or when shooting in iA mode.
• Auto-ISO mode.
• iDynamic auto-contrast mode.
• i.Resolution mode.
• Motorized zoom lens operation.

I've tested and confirmed these features to work reliably at 60Mbps in 1080i FH and 720p H video modes. The 60Mbps FH and H video modes also support 4GB file-spanning on 30MB/sec Class 10 SD cards, and produce excellent motion picture quality that is just a notch more compressed than Flow Motion's 100Mbps FSH and SH video modes.

Flow Motion v2.02 Patch Settings File

This zipped INI file can be used to apply complete patch settings to firmware loaded into PTool 3.65d. To use, unzip the INI file into the same folder as the PTool application. Launch PTool and load the firmware v1.1 binary file for GH2. The settings contained in the Flow Motion v2.0 INI file will automatically be installed in the "F" 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 GH2 v1.1 firmware into the camera. You may also copy each patched or original firmware file to separate SD cards, and use them to quickly switch between patches as often as you like.