Wednesday, 1 December 2010

Testing the effect of the GH1 hack

For a while now, it has been a well known fact that the Panasonic Lumix GH1 firmware can be adjusted to yield higher video bitrate, among other things. This is referred to as using "the hack", or "hacking" the GH1. Similar adjustments can also be done to the GF1 and G2 cameras.

I wanted to test the effect of the hacked GH1. Is it possible to measure the improvement of the video after installing the hack? I know many people have praised the quality of the hacked GH1 video before, but I wanted to make sure this test has exactly the same moving subject and lightning before and after installing the new firmware.

Test setup

Here is my test setup:


The camera is on a tripod, with the Leica Lumix 45mm f/2.8 macro lens. The camera is set to f/5, 1/60s, ISO400. The LEGO figure is on a platform that rotates at a constant speed.

I recorded one video file before installing the hack, and one after. When adjusting the firmware, I upped the max bandwidth from 16,000,000 to 50,000,000. Both videos were recorded at Full HD, 1920x1080 pixels. This can only be done using the AVCHD format. My camera is the PAL version, meaning that I get a framerate of 25fps.

The first video is 11s, and 20,754,432 bytes, 1.89MB/s. The second video is also 11s, and 31,395,840 bytes, 2.85MB/s, 50% higher than before the hack. So already here there is an indication that the hacked video contains a higher bandwidth.

Video examples

Here are the videos. You can double-click on the video to get to the YouTube page, where you can see them in higher resolution, up to 1080p.

Before the hack:



After the hack:



Of course, just watching the videos on YouTube isn't enough to judge the quality. For an extra test, I have made some framegrabs from the videos, to compare the quality.

First, two full size framegrabs from the video.

Before:


And after:


It's still difficult to compare the quality of the images. Here are 100% crops from the 1920x1080 framegrabs. I chose four consecutive frames from each video stream. Click on the image for a larger version.


Conclusion

Based on these screenshots, I believe it looks like the there is some more clarity and sharpness in the hacked video stream. Also, the colours are more washed out without the hack. The hacked video stream is better. But from my experiment, I don't see a dramatic difference.

Other effects

After recording the second video, I was not able to playback the videos any more. Just showing the thumbnail in the viewer was enough to freeze the camera. To reset it, I needed to remove the battery. Just flipping the on/off switch was not enough. This is, of course, quite annoying.

2 comments:

  1. Your calculation for the bitrate is off by a factor of ten! It should be 2.85MB/s or if you wanted it to be in Megabit instead, 22.8Mb/s.

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