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GH2 Stalin samples topic
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  • @plasmasmp how did you get 12800iso??
  • @Mark_the_Harp
    Yeah, there's much bigger I and P frames at the higher ISO. Although, both sets of footage have banding in the corner of the ceiling.
  • You need an electronic lens, put camera in shutter priority mode, and boost EV level to as high as it will go. Auto ISO as well. To know your true ISO, shoot a still in manual mode to compare.
  • @Shield Thank you so much for posting my video. I have made a version for Vimeo. I had to compress it to make the 500MB cap. It is 25-50mbps VBR so you can at least download that file and the quality is better than YouSchmoob. Just go back to page one of this topic to see it.
  • @sam_stickland Interesting looking at the bar charts, even the unhacked GH2 shows a low bitrate for the first I frame and hence, for the first GOP, just like is happening (but far more obviously) in the hacked versions.

    Also I'm wondering if @EOSHD is right - forcing a low GOP would take away at least some of that banding by raising the data rate, in other words that the banding is caused by low data rate rather than (as I believe) low bit depth / lack of dither.
  • APXmusic - I had to take it down for a while. It's slow, but should be steady. Better than nuttin' for the original!
    Link to APXmusic's raw file:
  • +1 with @chip. 3-GOP 75Mbps solves, just like all other patches, only a few technical issues. Macro blocks, low details, ugly noise. The rest are WB, DR, lighting, framing, film mode, rolling, moving, editing, color grading, and many other aspects. Some took amazing videos with unhacked GH bodies. The GH patches make their good videos better. Nothing more or less.
  • @Mark_the_Harp

    I took the 160ISO still you posted and added some gradients to it in 8bit to show that 8bit itself is capable of representing the gradients without banding. Just some quick linear gradients in photoshop mind, nothing fancy.

    Update: I added some monochromatic gradients and some slight banding is visible but it's nothing as pronounced as the gradients the GH2 is producing in these low-light situations. This is why I believe it's compression that causes it and not the 8-bit representation.
    1920 x 1080 - 162K
    503 x 600 - 39K
  • @sam_stickland That's really interesting and thank you for testing that out. So can I lower the banding by lowering the GOP or raising the bitrate? Or is it neither of these?

  • just 24h 42mb patch
    shot shaky with ExTele 25mm at 0.95 1/100 400ISO soft
    uploaded H264 1080p main 4.2 average 37mbps max 42mbps
    normal GOP
  • @Mark_the_Harp I'd say increase the bitrate. Or increase the efficiency of the codec so it makes better use of the bitrate it has (obviously this uses more processing power to encode). [*]

    Now.. which combination of AVCHD settings causes either of these to happen on the GH2 is a different matter - hence all the testing that's going on!

    For example, in a high-quality, non-realtime encoder a longer GOP rate would usually result in more detail as the codec is making better use of the available bitrate . But on the GH2 it appears I frames are - by default - encoded with higher bitrates than P and B frames, so perhaps lower GOP rates result in a higher bitrate.

    It's also possible that low-detail or low-brightness areas are automatically having their available bitrate reduced.

    Careful testing will reveal all!

    [*] Maybe there's a minimum macroblock size setting somewhere too.
  • Low light, high ISO test (3200-6400)
    Lumix GH2, Canon FD 50mm f1.4
    Stalin hack, AVCHD kae's 60MBit 1080p@24 GOP3
    Closeups in ETC mode
    No grading
  • @Vitaliy_Kiselev
    "We are working on quantizer to make bitrate in low light better."

    Thanks Vitaliy, That's great news. This is probably one of the most important improvements needed for the GH2. I sure wish Panasonic could of offered a user option for a constant bitrate.
  • I've done the default hack on the GH2 and am amazed at the boost in quality. For instance the image of the cat where it's head is blurred perfectly just would not happen with an unhacked camera. Fast motion particularly is reduced to blocky ness because the encoder just guesses. I regularly shoot fast moving kids playing sport and at times the image is incredibly poor, when combining panning with fast action. The camera was set with a shutter of 100 for 720p50. This looks like very "filmic" blur in my opinion. In general the image is incredibly sharp for a video still.

    The next image is one where there wasn't much movement, cat wise. Lens used was Voigtlander .95 25mm. Again the level of detail for 720 is astonishing.


    My only gripe with the hack is that the first few frames, maybe 8 or so are garbage. Not a deal breaker but it would be nice to not have these, as on the camera the thumbnail is taken from the first frame. Is there any way to avoid this.

    Other great thing about the hack is shadow detail. This was I think shot with either the Cinema setting ot Nostalgia to increase the perceived latitude. In bright sunlight you do have to stop way down to avoid burning out the highlights. The downside of this is lack of detail in shadows. This image is raw out of the camera and under the seat the detail is lacking

    Here's the same shot but with a curves adjustment in After Effects. I didn't go crazy with it but because the noise in the shadows and underexposed areas is greatly reduced by the hack you can pull out detail to give the image a greater latitude. In motion there is little in the way of noise
    1280 x 720 - 215K
    1280 x 720 - 236K
    1280 x 720 - 130K
    1280 x 720 - 338K
    1280 x 720 - 348K

  • Really unreliable 720p at 50mb+ at high shutter speeds is great for twixtor. Most times I could not record for more than a few seconds at a time.
  • @Sage what settings did you use for "Jay" ISO, shutter speed, etc. And what settings did you use on the hack? That looks amazing!
  • @APXmusic

    Thank you APX! It was kae's extreme, at iso 800, 1/60 shutter, and f2. (& smooth -2)
  • @sage Did you transcode your material before editing, and if so what did you use and what were the settings. Good Work.
  • @Bueller

    Thank you Bueller; it was edited in native avchd. CS5.5 is great.
  • hi,
    has anyone tried to shoot more than 30min with high bitrate?
    I'm considering hacking my gh2 to shoot a concert comming soon, but i need my gh to hold more than one hour.

  • Terrence Malick Inspired
    Kae's 3gop 65mb settings, shot at 24p @ 1/50th