@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.

@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.

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: http://pep.goldcomics.com/Snack_Bar/Stuff/Soshuji_Yakuyoke_Daishi_Temple.zip

@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.

@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.

@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

@APXmusic

Thank you APX! It was kae's extreme, at iso 800, 1/60 shutter, and f2. (& smooth -2)

@Bueller

Thank you Bueller; it was edited in native avchd. CS5.5 is great.

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