GH2 official discussion thread

cbrandin said:
I've only seen a couple of 720p clips that are claimed to be from a GH2. Either they didn't change the 720p encoder at all, or the clips aren't really from a GH2. There are no B frames in the clips and they do not support 24Mbps, so there isn't any potential quality improvement. Let's hope they weren't really from a GH2, or that Panasonic hasn't finished updating the 720p encoder yet.

Chris
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I have a feeling they were from a gh2 as the footage was very clean noise/banding wise. He was indoors, kit lens, and at the GH2 stand. Could the GH1 have been as clean as that?
 
The 720p30 MJPEG mode looks like it's got a bitrate of 25Mbit. That would probably beat using 720p60 @ 17Mbit if your final output was going to be 30p.
 
I guessing it is from the PAL version. I didn't do a conversion. It's 50p footage in a 50i wrapper. That's not the same as actual 50i. I assume it will convert to 25 unwrapped progressive just fine. The 24p clip is actually native 24p - no pulldown removal necessary.

Chris
 
Yes and now the next step will be global shutter.... I think the real GH2's will have B frames ,as is always the case protos have to go out the door at the last minute for the show and 9/10 times they are not complete...As a guy who has stayed up all night in Vegas hotels working on prototypes to get them working for the CES the next day this is the reality of doing trade shows....

I believe that these are the new sensors or protos but they are not set up properly yet ....The footage does look different....

But if no B frames No upgrade.. I am still keeping at least 1 GH13 either way ..

HDMI output for recording to nanoflash ...I would love to believe it ...but I doubt it ...would affect Af100 sales

Time will tell

Hey can we run a betting pool on HDMI out .....

Man I would lobe to be wrong about that


Larry
 
marcram said:
I believe the 25p in 50i wrapper is solved by shooting at exposures less than 50 Hz as previously discussed.

Likewise, we should be able to get 30p in a 60i wrapper by shooting less than 60 Hz. Two consecutive fields will be acquired from the same temporal exposure.
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If that's possible, sure, but you sacrifice being able to use ANY faster shutter speed. Not very flexible. Not having 25p is seriously dumb.
 
cbrandin said:
Attached are screenshots from the GH2. One is the 24Mbps 1080 24pN mode, one is 17Mbps 1080 25pW mode, and the third is 17Mbps 720 50p mode (you can tell which is which by looking at the labels or the Info Panels).
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Chris, thanks. 24P mode looks interesting at low level. Interesting as in "good." I'm curious what StreamEye will show. My guess is that changes you are seeing at packet level are due to implementation of proper NTSC framerate - 23.976. GH13 AVCHD encoder in native mode outputs 23.971. Or at least that's what the meta-tags say. I can't think of what else would have changed.

Also, by all accounts 1080i mode is the real [crappy] interlaced mode, not 25p in 50i wrapper like it is on GH1.
 
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cbrandin said:
Really? Can we confirm this? If that is the case I need to change how Stream Parser reports it.
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Well, that's only way to achieve the smooth motion video look in 1080i mode. 25p in 50i wrapper is apparently too "cinematic" for the nebulous Panasonic customer. Raw MTS files of this footage are not yet publicly available, but Vitaliy had some sent to him and confirmed the finding in his 43rumors.com interview.
VK: And we do not even approached famous 50i mode with 17Mbits.
VK: I really like the idea of 50i. It had been my secret dream for GH2.
VK: But people are people. They just hate deinterlacing of HD H264 footage.
icon_smile.gif

VK: They had been looking for 1080p50.
VK: Look at all still review sites.
VK: GH2 introduced some minor improvements
icon_smile.gif
Like interlaced 50i mode, instead of proper p25 mode.
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Nothing, just states: GH2 example video - slow motion. Resolution could be worse, cause of youtube-compression.
 
This may have been mentioned before, but I just "grokked" another benefit of the GH2's new Extra Tele Conversion function: When used with a non-constant aperture zoom lens, ETC can make the lens "faster/brighter" in certain situations.

Instead of zooming the lens itself (and thus darkening the image because of the lens' non-constant aperture), using ETC "zooms in" w/o affecting exposure.

So, for example, the relatively inexpensive 14-42mm kit lens can be used at its 14mm focal length @ f3.5 max. aperture, but with ETC yields 36.6mm (2.6x) w/o ramping the f-stop and darkening the image.

Another benefit: ETC "looks through" the center of a lens, usually the sharpest part.

It'll be interesting to see how well an Extra Tele Conversion shot intercuts with the same scene & lens setting recorded w/o ETC. (e.g.: Cutting back & forth between the wide shot & the ETC close up.)

Cool stuff.

EDIT: Oh, and there's also the effect that the ETC "zoom" doesn't change the depth of field. So, for example, if a 14mm lens is in use when ETC is turned on, the resulting angle of view will be that of a 36.6mm lens, but the DOF will be that of the 14mm lens.
 
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svecher said:
Well, that's only way to achieve the smooth motion video look in 1080i mode. 25p in 50i wrapper is apparently too "cinematic" for the nebulous Panasonic customer. Raw MTS files of this footage are not yet publicly available, but Vitaliy had some sent to him and confirmed the finding in his 43rumors.com interview.
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If anyone can say to me how this can be 25p in 50i wrapper, I am ok (this is small part of 1080i50 thing):

1285381874.jpg


It is clear that fields are from different source frames and this is interlaced footage.
 
Peter J. DeCrescenzo said:
Instead of zooming the lens itself (and thus darkening the image because of the lens' non-constant aperture), using ETC "zooms in" w/o affecting exposure.
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It's a great idea but I keep wondering how is it going to do it? There will have to be transition zones from wide angle, where the standard binning/skipping routine is used, to full zoom, where every pixel is being sampled. So how will it get from point A to B? I'm assuming it will use different binning routines along the way so you may notice quality/resolution changes as it jumps from binning mode A to B and finally to none (it may be fixed increments and not a constant zoom, something someone who saw the camera may be able to confirm or deny).

I also wonder how far in will you have to zoom to reach the full scan mode. If full sampling starts before you reach maximum telephoto then the optimal image quality should occur right at the zoom length when the full sensor scanning mode starts in. If full scanning kicks in at something, say, when the image window is down to 2560x1440 it should yield the best IQ since you'd have a full scan but it'd be (presumably) downsampled the way still images are. To me it's the most interesting feature of the GH2
 
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