GH2 official discussion thread

[AdrianF]

I'll agree with what was said earlier in the thread. Panasonic have presumed that they have made a good choice for the target market, by making the camera 50i and that is probably true to a certain extent.
They have however made a big mistake by dropping progressive 1080 25 ( if that is the case ), though it won't be the first camera produced that had a head scratching omission in it's features.

 

[AKED]

Well, they took the risk with TM700, which is even more of a consumer style cam and that seems to have worked out ok.

Not really. According to a Panasonic Manager is the 1080/50p mode not compatible to Panasonic TVs which seems to be a problem for them.

 

[RobertKM]

Yes - this is interlace video which is what I was describing.




I understand that the GH1 is 25P frames in a 50i "wrapper"....but that is then progressive footage....ie not what I would call interlace.



All reports so far about the GH2 that I read have described the output as "analog tv/VCR style interlace" as you call it...ie no true progressive frames....this is why we hear so much "moaning" about the GH2....there is no true progressive frames even in the 50P mode....I would love to be proven wrong on this...does anyone know for sure that the GH2 doesnt have true progressive frames? Barry?

Well, you can see for yourself with this file. It does require deinterlacing, but once you do that, it looks like true progressive frames to me.
http://pliki.optyczne.pl/gh2/film/00001.mts
http://www.optyczne.pl/3388-nowo%C5%9B%C4%87-Panasonic_Lumix_DMC-GH2_%E2%80%93_zdj%C4%99cia_i_filmy_przyk%C5%82adowe.html

 

[kainekainekaine]

Some people have said footage deinterlaced will be 1920x540 @ 25 FPS or 1920x1080 @ 25FPS. Just wondering anyone know for certain which it will be? Also what mode will people be using to get slow mo now, the old 720 50p/60p or the new 1080 50i/60i? How well will this work mixed with the 1080 24p footage. Cheers

 

[svecher]

Not really. According to a Panasonic Manager is the 1080/50p mode not compatible to Panasonic TVs which seems to be a problem for them.

I looked at Panasonic global TV website and all of their current 1080p models claim to support "Full HD." Wikipedia article on Full HD informs us that 50/60p modes have been been part of ATSC broadcast standard since 2008. HDMI, a consumer standard for interconnection of HD-capable devices has supported 1080p60 since rev.1 (2003). I don't know the specific details involved in the problem you have been told about, but from the perspective of specifications and compliance to standards I can't see why there would be a problem.

 

[Barry_Green]

Point is, though, it wouldn't actually cost them anything to satisfy *everyone*

I know what you're saying -- and from our perspective, I agree with you. But it actually does cost them -- for every customer who complains about how "stuttery" the video is, they have support hassles they have to deal with. And for making the modes and supporting them, they've got programming and debugging time and on and on. And the more complex they make the camera, the less appealing it is to the entry-level/low-end customer.

BTW - when you say the available modes are 50/60p & 50/60i - presumably you mean that the sensor captures 50/60p, but outputs 50/60i?, or have I misunderstood? - it would be nice if there were 50/60p modes.

The sensor output is 60p or 50p. When I said available modes, I meant 1080/50i & 60i, and 720/50p & 720/60p.

 

[jerodequin]

I've had a go with the file....

I've had a go with the file....

Well, you can see for yourself with this file. It does require deinterlacing, but once you do that, it looks like true progressive frames to me.
http://pliki.optyczne.pl/gh2/film/00001.mts
http://www.optyczne.pl/3388-nowo%C5%9B%C4%87-Panasonic_Lumix_DMC-GH2_%E2%80%93_zdj%C4%99cia_i_filmy_przyk%C5%82adowe.html

And have to admit, if I import the mts file into premier onto a 1080p 25fps timeline as I do with GH1 1080 footage then the result looks good and does not seem to show any deinterlacing artefacts.....

Maybe I'm doing something wrong??

 

[svecher]

Well, you can see for yourself with this file. It does require deinterlacing, but once you do that, it looks like true progressive frames to me.
http://pliki.optyczne.pl/gh2/film/00001.mts
http://www.optyczne.pl/3388-nowo%C5%9B%C4%87-Panasonic_Lumix_DMC-GH2_%E2%80%93_zdj%C4%99cia_i_filmy_przyk%C5%82adowe.html

Well, don't forget that viewing footage at lower resolution hides some of interlacing defects. Even then, nothing can be done about defects related to motion.



Reviewing frame grabs at original resolution makes all interlacing artifacts quite visible.
1900x1200 frame grab Deinterlaced
1900x1200 frame grab Interlaced.

 

[RobertKM]

You're doing it wrong.


Here's the full resolution:
http://img98.imageshack.us/img98/4656/25pdeinterlaced.jpg

I don't have any editing software with me, so I simply deinterlaced it in VLC using X mode. It then plays back just as if it were a 25P file.

EDIT:
No, I was wrong, svecher is right. VLC was simply interpolating half the vertical resolution.

 

[Svart]

The real question is "how does panny get that interlaced footage?". Is it true interlacing where each frame is truly captured as an interlaced frame or is it a case of a single progressive frame that was divided by the software into two interlaced frames?

If it's the first one then de-interlacing will always cause interlacing artifacts because the two frames will always be out of sync with each other.

If it's the latter, then combining the two frames will yield a perfect progressive frame since it's just a division of a progressive frame to begin with.

We need more information, and less guessing.

I'm thinking it might be the latter since the sensor is native progressive. It could explain some of the things people are seeing with good results de-interlacing to 25p.

 

[Camera Expert]

Not really. According to a Panasonic Manager is the 1080/50p mode not compatible to Panasonic TVs which seems to be a problem for them.

Where are you getting this information?

 

[Matthew P]

The real question is "how does panny get that interlaced footage?". Is it true interlacing where each frame is truly captured as an interlaced frame or is it a case of a single progressive frame that was divided by the software into two interlaced frames?

As Panasonic have said themselves, the footage is 50i, not 25pf (that's 25p in a 50i wrapper). Deinterlacing craps up the quality considerably, especially when you do a frame by frame comparison. If you were to look at natively progressive footage on an HD screen against deinterlaced 50i, you'll see what I mean.

 

[svecher]

You're doing it wrong.
View attachment 24203
Here's the full resolution:
http://img98.imageshack.us/img98/4656/25pdeinterlaced.jpg
I don't have any editing software with me, so I simply deinterlaced it in VLC using X mode. It then plays back just as if it were a 25P file.

From VLC wiki

Generates a full picture taking the odd lines from the odd half-picture, and creating the even lines through a complicated algorithm that uses information from both half-pictures.
This may be similar to what 100fps.com calls Area based?

What this means is further loss of real resolution. In the worst case scenario you lose up to half of original 1080 lines. Maybe the complicated algorithm "recovers" 25%, maybe not. This will be very hard to tell, as you'd have to shoot a moving resolution chart to know for sure. Don't forget that actual resolution of current crop of combo-cams in 1080 mode is at best ~720 lines due to aliasing. So in the worst case scenario (unless GH2 does significantly better in this department) you may end up with 360 lines of real resolution, less than SD.

 

[svecher]

The real question is "how does panny get that interlaced footage?". Is it true interlacing where each frame is truly captured as an interlaced frame or is it a case of a single progressive frame that was divided by the software into two interlaced frames?

If it's the first one then de-interlacing will always cause interlacing artifacts because the two frames will always be out of sync with each other.

If it's the latter, then combining the two frames will yield a perfect progressive frame since it's just a division of a progressive frame to begin with.

Based on all available information it does neither. Sensor captures 50/60p at 1900x1200. Encoder takes the upper field from the odd frame and the lower from the even one. Maybe sequence is reversed, but this I believe is the general principle.

 

[cbrandin]

I've looked at the GH2 1080/50i footage - it's definitely interlaced and not wrapped progressive frames - unlike the GH1. You can tell by single stepping through each frame - if there is one image it's progressive, if there are two it's interlaced. If you look at the clip in an editor that is set up for interlaced footage and single step, the image will change every second frame if it is wrapped progressive and every frame if it is interlaced. Remember though, by the time the GH2 is released this might change.

Chris

 

[RobertKM]

From VLC wiki
What this means is further loss of real resolution. In the worst case scenario you lose up to half of original 1080 lines. Maybe the complicated algorithm "recovers" 25%, maybe not. This will be very hard to tell, as you'd have to shoot a moving resolution chart to know for sure. Don't forget that actual resolution of current crop of combo-cams in 1080 mode is at best ~720 lines due to aliasing. So in the worst case scenario (unless GH2 does significantly better in this department) you may end up with 360 lines of real resolution, less than SD.

You're right. I stand corrected. Looking closely at VLC's anti-aliased frame, I can see that it is losing around half the vertical resolution. Sorry about that.

 

[svecher]

You're right. I stand corrected. Looking closely at VLC's anti-aliased frame, I can see that it is losing around half the vertical resolution. Sorry about that.

No problem, it's a learning process for all.

 

[jerodequin]

Does Adobe Premier automatically de-interlace footage? I've been doing what I always do with GH1 footage, just dropping it into a 1080p 25fps timeline (which of course works for the GH1 as the content *is* 25p on a PAL body).
'
Interestingly, Premier identifies the GH2 footage of the car linked here earlier as 1280x1080 25fps. I've exported it as single frames and got the following sequence:

http://cid-a2b1df5e50fe44ef.photos.live.com/self.aspx/Frames%20Test/Sequence%2001001.jpg

As someone mentioned, you would have to shoot a resolution chart to really be sure, but as it stands, the footage looks pretty good.... I would like to have some more mts files from the GH2 to experiment with!

 

[svecher]

Does Adobe Premier automatically de-interlace footage? I've been doing what I always do with GH1 footage, just dropping it into a 1080p 25fps timeline (which of course works for the GH1 as the content *is* 25p on a PAL body).

I didn't try that, but it's logical to assume that if you drop 50i footage into 25p timeline it will be conformed appropriately (deinterlaced).

Interestingly, Premier identifies the GH2 footage of the car linked here earlier as 1280x1080 25fps. I've exported it as single frames and got the following sequence:
http://cid-a2b1df5e50fe44ef.photos.live.com/self.aspx/Frames%20Test/Sequence%2001001.jpg
As someone mentioned, you would have to shoot a resolution chart to really be sure, but as it stands, the footage looks pretty good.... I would like to have some more mts files from the GH2 to experiment with!

Testers for that Polish website also took a video in 24P mode. Download the file titled "AVCHD, tryb 24P CINEMA, 9 s, 1080i [sic], 23 MB" (It's actually 1080p/24, not i). Watch at true 1920x1080 resolution. The difference in amount of details to my eyes is quite clear.

 

[jerodequin]

Yes, the difference in the 24p file is very noticeable - it's a lot sharper for sure!