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Nino Film Blog | June 22, 2024

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Tester13’s GH1 firmware hack – first user impressions plus before / after footage comparisons

Tester13’s GH1 firmware hack – first user impressions plus before / after footage comparisons

As many of you already know, somebody by the name of “Tester13” has released an incredible firmware hack for Panasonic’s GH1 camera that enables this amazing camera to record at higher bitrates, which makes it a beast of a camera.

For the second blog post in a row, I will feature the content of someone else, this time fellow Viennese filmmaker Gunther Machu. While I do not own the camera, Gunther is an avid GH1 cinematographer who recently literally amazed me with his macro short film that he shot of animals in his garden (notably shot WITHOUT the firmware hack). I embedded it at the bottom of this blog post. You can find him on Twitter right here – Gunther, start posting more though 😉

The following is Gunther’s take on Tester13’s firmware hack and I am happy to have it exclusive here on my blog:



The GH1 was first released in Japan by the end of April 2009. It created a lot of hype, mainly because the specs looked very promising: AVCHD Full HD 1080p with 24/25fps (in a 60i/50i wrapper, requiring pulldown on the NTSC model), 720p with 60/50fps (NTSC/PAL model), 720p motionJPEG with 30fps in a compact body with a 4/3” sensor. Add 48kHz built – in stereo mics plus interchangeable lenses without a mirror, thus allowing enough space to fit virtually any lenses out there via appropriate adaptors.

The hype soon cooled down a bit when first tests revealed a rather weak codec, showing that the 17Mbits/s FHD AVCHD was just enough for static shots, starting to exhibit compression artefacts already with reasonable camera movement. The main problem originates from the AVCHD implementation without B frames and a long GOP structure including only P and I frames.

Many users still preferred the GH1 over the famous Canon line, mainly because of the superior performance regarding aliasing, resulting from the fact that the GH1 seems to do pixel binning instead of Canon’s line skipping in their DSLR lineup. (Check out Nino’s blog post on the way the Canons do line skipping right here.)

Tester13’s GH1 firmware hack

Believe it or not, on the 11th of April the previously unknown guy Tester13 showed up on, asking for volunteers to try first patches of a firmware hack that he provided. His approach was / is to provide a firmware manipulation tool which allows each GH1 owner to manipulate the firmware of their cam. Based on the first successes dvxusers quickly started to donate money to provide Tester13 with equipment, as he initially didn’t even own a GH1.

If you want to join in and help as well, please donate at

With amazing speed this guy quickly patched the most annoying drawbacks of the GH1, namely native 24p (thus eliminating the need for pulldown), language (allowing Japanese models to be changed to all other languages) and many more. The thread quickly moved to research the AVCHD and MJPEG codec implementation, and resulted last week in a major breakthrough: the patch now allows to change the size of the P frames in the AVCHD implementation (originally it was limited, and heavily over-compressed as soon as motion kicked in), pushing average bitrates up to 50Mbit/s, thus eliminating all the codec weaknesses known so far. As if this wasn’t enough to make everybody happy, MJPEG patches allowing to increase bitrate and changes to the frame size were released as well, resulting in up to 100Mbit/s photoJPEG (75%) at user defined resolutions. Latest status of research is a patch to enable 4:2:2 chroma subsampling in the MJPEG codec.

Note: as with every hacked firmware, this is not 100% risk free! You do everything at your own risk.

Footage with the patch released on 12th of June, Ptool 3.36

I did some tests with the patch released on 12th of June, and was interested to get into a side by side comparison of the original GH1 and the patched one, GH1³ – an homage to Tester13 😉

The following settings were posted by PappasArts (MJPEG) and Jobless (AVCHD), over at

In this test a pan through my garden was used, with the following settings:
MJPEG: size 1440x1080p (also 1920x1080p available), E1 (Q/T) = 384/24, E2 (Q/T) = 330/24, E3 (Q/T) = 300/24, E4 (Q/T) = 276/24
AVCHD: 24p native, Video buffer 50M, video bitrate adjustment: 38M, overall bitrate adj. 40M, limiting bitrate adj. 42M

I limited the bitrate somewhat as I only had a buffalo 16GB Class 6 card available. For higher bitrates, faster cards are needed otherwise the camera can freeze during recording (remove battery and everything is fine again).

It took me about 15 mins to revert the firmware, hence the light in the before / after test had changed a bit. Still, I think the results speak for themselves.

Other settings: camera fully manual, smooth film mode, everything set to -2 to get the flattest possible image, 1/160 shutter speed, WB at 5300K, Iso 100, F8 on the kit lens.


The pan starts with a static (tripod) scene:

AVCDH 1080p static 1 - WARNING: pop-up opens in 1.920x1.080 resolution

Then the pan starts:

AVCDH 1080p static 1 - WARNING: pop-up opens in 1.920*1.080 resolution

Stopping with a static scene again:

AVCDH 1080p static 2 - WARNING: pop-up opens in 1.920x1.080 resolution

200% zoomed in, looking at some details:

AVCDH 1080p static 2 - WARNING: pop-up opens in 1.920*1.080 resolution


Moving scene 1 - WARNING: pop-up opens in 1.920*1.080 resolution

Static scene 2 - WARNING: pop-up opens in 1.920*1.080 resolution


Congratulations, Tester13 and all the other brave guys who dared to test the first firmware patch versions, risking to brick their camera (Nurbs, jobless, PappasArts … at!

The clear winner at the moment (research still ongoing, settings not consolidated) is the new 1080p native AVCHD. Not only has the famous “mud” during camera movement vanished, also in static scenes the resolution has improved. An explanation (apart from increased bitrate) could be the fact that in the original 60i wrapper containing the 24p footage the chroma was interlaced and had to be deinterlaced during pulldown. With native 24p the chroma information is also progressive, resulting in a slightly higher chroma resolution. Furthermore, the original GH1 was showing “islands of unsharpness” in areas where the contrast level was low, thus making wide angle shots with deep focus problematic in difficult, low contrast light. This has vastly improved as well, resulting in a whole new camera!!!

It is hard to predict what comes next, but Tester13 has already eliminated the most pressing weaknesses of the original GH1 at lightning speed, making his initial thread the most successful ever on, currently exhibiting ~320000 hits. If MJPEG 4:2:2 works at high bitrates, another quality step is to be expected! Exciting times.


Thanks so much to Gunther Machu for this great post! I can’t wait to meet up with him in Vienna soon to see the difference hands-on and maybe even do some side-by-side comparison to footage from my Canon T2i/550D.

Please do check out Gunther’s macro video I was talking about in the beginning, I think this is some of the best work I have seen coming out of that tiny GH1 camera. Again, please note that he shot that with an unmodified GH1 and the original codec, using an old used Canon 50mm macro FD lens that he got from eBay for only €50!

Apparently the GF1, GH1’s little sister camera, was hacked as well. Check out the demo video:

UPDATE 21st June, 2010:
Now that the firmware hack has been out for a week, more and more interesting videos demonstrating the added possibilities have popped up on the web. I have selected a few that I think show best what is now possible with these cameras. (Don’t get me wrong – these videos aren’t masterpieces, but they do show what the GH1 is now capable of – some shots in there would have been impossible to do with the original firmware.)


  1. Dude awesome post. Can’t wait to get my hands on a GH1

  2. Thanks for sharing this great info and for introducing us to Tester13. Great work guys!

  3. Wow, nice post. Thank you Nino for the insides.
    Seems like a great cam the GH1. Love the color rendering.

  4. Otto

    Sorry but in the examples above I can’t see any mind blowing differences. The pan through the garden looks pretty much the same to me. I downloaded the full size from vimeo by the way.

    • Gunther

      Dear Otto,

      as a general remark we are really talking about pixel peeping here ;-), which means details which normally go unnoticed by most of the people.

      The most noticable difference (which can only be seen if you go frame by frame) is the level of detail in the trees and the grass. Also, above the garden house in the dark areas you cannot see any detail in the original footage, but a lot of detail in the patched one.

      If you look at the moving scene comparison picture above (the second last), the level of detail in the trees with the patched codec is much much better.

      These are just a few examples.

      • Otto

        Thanks a lot for the reply Gunther. Yes I can see these details I just hoped for a much higher improvement that would be noticable at first glamce even for Otto Normalverbraucher. But anyway it’s great that tester13 gave you some more control over your camera. Things that should have done by Panasonic in first place. Enjoy your new GH13 I will take a close look at the GH2 when it comes out.

  5. Dinesh Bhadwal

    Hi Nino, I am new to your site. Amazing work done by you for someone who is looking to move into DSLR video. Until now i thought the best deal for someone like me is Canon T2i. Have things changed with Tester 13s hack? Is Panasonic GH1 better than canons with this patch? Considering GH1s moveable LCD, great HD stock lens, follow focus capabilities, sound options, small size etc., shouldn’t GH1 be the first choice for DSLR video? I think a comparision of GH1 with a Canon T2i would be great!

    • Hi Dinesh, will try and do a comparison next week. I simply don’t know the answer to your question yet. The advantage of the whole T2i/550D infrastructure is that you don’t have as much magnification (1.6x instead of 2.0x with the GH1) when using 35mm lenses. I simply don’t know the GH1 well enough to do a judgement on that, but I will meet up with Gunther (who is an expert on the GH1) and we will do some test shoots to compare the two.

      • Dinesh Bhadwal

        Thanks Nino. Waiting for the comparison.

  6. oneted

    I like the updated summaries that you posted.I get so confused with DVXusers threads that I cannot keep up with them.While you simply placed the whole thing so clear.Thanks buddy and do keep posting the latest….

    • Thanks, but that credit goes to Gunther Machu who is THE expert on the GH1!

  7. Jay

    Nino, I have shot stills with both the GH-1 and 550D. While there is a difference in the crop factor (1.6 vs. 2), it is not really apparent in the actual results. You certainly get a different aesthetics when you shoot with a 5D Mk II because its sensor is lot bigger than both the GH1 and the 550D. I find that GH1 just has better ergonomics for video and makes a really good hybrid camera for a one person crew. M43 system doesn’t have L series lenses like Canon but makes up for it with adapters available for all kinds of lenses making it cheaper for an amateur photographer/filmmaker to expand the selection.

  8. Well done, Nino!
    I tried the same settings, though, and my GH1 couldn’t record more than still objects, any movement, from the camera or form an object, made the recording stop… it would really help to publish all the options ticked and their entire numbers so that beginners like me could also make it work.

  9. Is that the new tendence on video?

    with a photo camera?


  10. Viktor

    Oh… please, do not actual and real, all new GH1s with preinstalled v1.3 firmware is not hackable.

  11. David

    Nino, is there a similar hack for bit rate increase with Canon or Nikon or any other camera?

  12. Sidney

    Hello, thanks for this GREAT information. Just one thing..

    Is all gh1’s hackable, or is it just some.. how would i know/check if its hackable ? ( want to buy one.. today!)


    • Viktor

      all new in the shop from 3/4 of y 2009 is not hackable. Old cam GH1 is actualy not in the sale.

      Please look for a Sony a55, is the same quality and better price /autofocus include/.

      compare on

      GH1 unhacked: compress “mud” and rolling shuter effect is in the FullHD very visible. In HD /720p/ mode has picture too bad sharpnes in edges /contrast sw/.

      I have this cam, do not buy it for HD video.

      For home video buy …SD600, tm750. For pofesional use …Red One ..or some.

      • Sidney

        i found one selling it with “WE9H” in the beggining of the serialcode. Does it work ? H is..August 2009?

        But the A55 overheats, right ? And is not hackable?
        if it overheats after 6 mins its quite useless, or what do you think ?

        The Gh1 hacked seems like an awesome / cheap camera for the things you get.. looks like a 5dmarkII video wise?

        Thanks for your response Viktor

    • As far as I know, any new GH1’s are not hackable any longer. Not sure if somebody made progress on hacking it again.

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