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Clearity about GH2 video modes/ frame rates

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Neil Redman
Clearity about GH2 video modes/ frame rates
on Jan 21, 2012 at 6:52:47 am

Hey, I was hoping somebody could give me a little advice on the Panasonic GH2 video modes and tell me if I figured them all out correctly. I find them to be named pretty confusing and generally they don't tell you the frame rate. By the way I got the PAL version of the camera and I'm editing all my footage so some of the modes are pretty useless to me.

I also just updated to the newest firmware so I got the Hight Bit Rate mode as well now. So basically as I understand the modes:

Lets start with the VARIABLE MOVIE MODE:

80% = 30fps = might be useful for a small amount of slow motion or to shoot for NTSC format

160% = 15fps = could only be useful in some really special cases, where you would like to speed up the footage and want it at exactly that speed instead of doing it in post.

200% and 300% = completely useless as you can do exactly the same in post production (unless maybe you wanted so save some hard disk space, but basically useless)


Then there is the MANUAL MOVIE MODE:

- It is described as being manual, because you can set the shutter speed and the aperture manually. Now this is a pretty stupid description as you can set them manually in any mode.

- Then I can choose Motion JPEG, which I would consider useless for a professional use/good quality images and the only advantage would be smaller file sizes

- AVCHD 1080i = 50fps (interlaced) = Only good if you really want to shoot Interlaced and it became somewhat obsolete with the firmware update to record 25p

- AVCHD 720p = 50fps (progressive) = Good option for slow motion. Am I right that there is no option to record 720p24 or 720p25?


And finally there is HIGH BIT RATE and 24P CINEMA:

- They have the same bit rate (24mbps) and therefore the name HIGH BIT RATE is confusing again. (Only difference is in 24p you could change the bit rate to a lower setting.)

- The difference between them is that one records 24p, the other 25p

- HIGH BIT RATE is RECORDED at 25 PROGRESSIVE but then stored in a 50i wrapper. Am I getting this right, that you could then in post just interpret the footage as progressive?


To sum it all up: The only modes one would really use is in most scenarios is 24/25p and 720p for slowmo!


So I'm sorry for the long post with all the numbers. I hope somebody could read through all the points and make sure that I understand everything and didn't make any mistakes. I really love what the camera can do but they named their modes in such a stupid way its unbelievable. Why can't they just let you choose resolution, frame rate and bit rate?

Cheers and thanks in advance!


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Craig Ricker
Re: Clearity about GH2 video modes/ frame rates
on Jan 21, 2012 at 8:24:59 am

Hey mate,

I'm not going to go into detail now, but just google GH2 hack, and go from there.
If you buy yourself a 64GB sandisk pro extreme (95MB/s card), with the latest hack, you can record 720p 60fps at ridiculous quality:

Top quality AQ3 720p burst w/ Seaquake
60p: 3 gop, 230k bytes* per frame, 7 seconds minimum
50p: 1 gop, 280k bytes* per frame, 9 seconds minimum
30p (80%): 1 gop, 770k bytes* per frame, 9 seconds minimum (original part of seaquake)

This turns a GH2 into a very cheap version of a RED camera. Something you dont want to miss out on, for just $200 on a new SD card and a hack :)

All the best


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Neil Redman
Re: Clearity about GH2 video modes/ frame rates
on Jan 21, 2012 at 3:07:56 pm

Hey, thank you for the advice. I was actually already planning on doing that pretty soon. I just wanted to make sure I understand all the modes I have right now on there, before I start modifying it.

I'm still hoping someone could have a read through my points and tell me if I made any mistakes.

Cheers


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Jason Jenkins
Re: Clearity about GH2 video modes/ frame rates
on Jan 21, 2012 at 6:46:32 pm

Sounds like you have got a handle on it. Now go out and shoot some stuff!

Jason Jenkins
Flowmotion Media
Video production... with style!

Check out my Mormon.org profile.


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Rafael Amador
Re: Clearity about GH2 video modes/ frame rates
on Jan 22, 2012 at 1:11:25 pm

[Neil Redman] "- HIGH BIT RATE is RECORDED at 25 PROGRESSIVE but then stored in a 50i wrapper. Am I getting this right, that you could then in post just interpret the footage as progressive?"
Right.
There is nothing like an "50i wrapper",
The clip is simply flagged as Interlaced.
Check it a Progressive.
rafael

http://www.nagavideo.com


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Neil Redman
Re: Clearity about GH2 video modes/ frame rates
on Jan 23, 2012 at 8:06:18 am

Okay, thanks everyone.

Just so I understand the 50i thing correct. I understand it that there are 25 frames captured a second, which are then transformed into 50 interlaced frames. Is that correct?

So would it then be enough to just check the footage as progressive (like in premiere under interpret footage) or do you have to do some kind of deinterlacing? Or does checking it as progressive already deinterlaces the footage?

neil


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Rafael Amador
Re: Clearity about GH2 video modes/ frame rates
on Jan 23, 2012 at 5:43:05 pm

[Neil Redman] "Just so I understand the 50i thing correct. I understand it that there are 25 frames captured a second, which are then transformed into 50 interlaced frames. Is that correct?"
No.
Don't get mixed up.
Interlaced and Progressive both have 25 FRAMES per second.
But Interlaced have 50 IMAGES per second while progressive only 25.

In interlaced you have 2 FIELDS per frame and each field belong to a different moment in time, there for you need to read the fields in a certain order.

The GH2 records what is called PSF (Progressive segmented frame). That means that instead of writing/reading the picture as Progressive (Line 1,2,3..) is read/write as Interlaced (Odd lines first, even lines after), but as long as all the lines belong to the same moment in time, the picture still looking Progressive.
Progressive picture can be read (interpreted) as Progressive, Upper First or Lower first and will keep looking Progressive.


[Neil Redman] "So would it then be enough to just check the footage as progressive (like in premiere under interpret footage) or do you have to do some kind of deinterlacing? Or does checking it as progressive already deinterlaces the footage?"
Just need to interpret as Progressive.
Although the file shows as Interlaced, there is really nothing to de-interlace.
There are no two different pictures inside each frame, just one.
Is just to tell to your NLE to read line by line (1,2,3,..), no field by field.
rafael

http://www.nagavideo.com


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Neil Redman
Re: Clearity about GH2 video modes/ frame rates
on Jan 23, 2012 at 10:23:18 pm

Ah now everything finally makes sense to me! Thanks so much that was a great explanation!


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