PDA

View Full Version : GH2 GH2 video modes - rules of thumb



bmcent1
04-17-2012, 09:25 AM
I'm new to the GH2 and enjoying the heck out of this camera. But I've read the manual and lots of reading on forums (for days! :) and I haven't found a concise explanation of the video modes yet that will help me film.

I'd like to shoot 1080 30p (or 1080i/60) in the best quality possible. But I'm also willing to try 1080/24 or even 720p for some shots if it means getting better video quality.

Are there any rules of thumb about modes that produce the best video quality? Within creative movie mode, generally lowest ISO, manual exposure and aperture, is the order:

1) 1080p/24 cinema High
2) 1080p/30 via Variable Movie Mode 80%, sped up 25% to be 1080p/30 if no sound needed
3) 1080i/60 HBR
4) 1080i/60 FSH
5) 720p/60 SH
6) 720p/30 Motion JPEG HD

If that list is wrong, but there are some generalizations, please correct it. Also, does the list change if HighISO is desired? I saw a recommendation to shoot in Motion JPEG in low light, lower detail situations to maintain bit rate.

bmcent1
04-17-2012, 11:51 AM
I did some testing today to try to get some general rules for myself. I was using a Sigma 150mm/2.8 macro with adapter to shoot a tiny spider in a web. This gave me a highly detailed "model" and tons of very out of focus background via shallow depth of field.

Here's what I found to be the best in terms of least noise (or in the presence of noise, I preferred film like over blotchier video looking noise):
1st - VMM 80%
2nd - 24H (very close to tied)
3rd - SH
4th - MJPEG HD
5th - HBR
6th - FSH

When it came to ETC / EX mode, the top two were the same but FH dropped down to the bottom next to FSH:
1st - EX VMM 80%
1st (tied) - EX 24H
2nd - EX HBR
3th - EX MJPEG HD
4th - EX SH
5th - EX FSH

This is with Sanity 5, but I hope it's generalizable to any patch/hack/settings that are reasonable and not broken.

I was surprised by MJPEG HD, it was grainier but seemed more film like and it also seemed to have a little more detail which might be a reasonable trade off sometimes. Thinking it will look great in B&W too.

After testing, I'm going to try to shoot VMM 80%, 24H, and SH as much as possible. If I need ETC/EX mode, I'll shoot VMM 80%, 24H, EX HBR, or MJPEG HD.

Still curious to know if others have a rule of thumb or if these observations should roughly hold true across different scenes, ISOs, and hacks.

mpgxsvcd
04-18-2012, 10:45 AM
You can't compare different modes at completely different bit rates. Some settings work better than other for specific formats.

Theoretically, the 1080p @ 24 FPS modes(EX VMM 80% is actually 24 FPS) will offer the most accurate representation of the scene if bit rates and everything else are kept constant. That is because it offers the highest number of bits per frame. The 1080p @ 30 FPS HBR mode would be next. Followed by the 720p @ 60 FPS mode and then the 1080i/60 mode.

The MJPEG mode is different because it uses a different compression scheme. If you make the MJPEG bit rate match normal AVC-HD bit rates then the MJPEG mode will show tremendous artifacts.

This video shows some examples of the same scene at different bit rates.

http://www.youtube.com/watch?v=vLDYyGQhYbc


http://www.youtube.com/watch?v=vLDYyGQhYbc

bmcent1
04-18-2012, 01:44 PM
Theoretically, the 1080p @ 24 FPS modes(EX VMM 80% is actually 24 FPS) will offer the most accurate representation of the scene if bit rates and everything else are kept constant. That is because it offers the highest number of bits per frame. The 1080p @ 30 FPS HBR mode would be next. Followed by the 720p @ 60 FPS mode and then the 1080i/60 mode.

This video shows some examples of the same scene at different bit rates.

http://www.youtube.com/watch?v=vLDYyGQhYbc


Thanks for the reply. That makes sense. I guess if there is a fixed bandwidth/data rate, then with fewer fps, you can have higher detail per frame of a given size.

I watched that video. Did new video modes come with the 1.1 firmware or is there another reason that Standard and Natural video modes were left out of the video.

I'm trying to read a lot and not ask too many questions :) But there are so many combinations of film mode, hack, video mode that i could never try them all out myself so any tips or conclusions that others have already found is a great starting point.

DPStewart
04-18-2012, 02:27 PM
You can't compare different modes at completely different bit rates. Some settings work better than other for specific formats.

Theoretically, the 1080p @ 24 FPS modes(EX VMM 80% is actually 24 FPS) will offer the most accurate representation of the scene if bit rates and everything else are kept constant. That is because it offers the highest number of bits per frame. The 1080p @ 30 FPS HBR mode would be next. Followed by the 720p @ 60 FPS mode and then the 1080i/60 mode.

The MJPEG mode is different because it uses a different compression scheme. If you make the MJPEG bit rate match normal AVC-HD bit rates then the MJPEG mode will show tremendous artifacts.

This video shows some examples of the same scene at different bit rates.

http://www.youtube.com/watch?v=vLDYyGQhYbc


http://www.youtube.com/watch?v=vLDYyGQhYbc

This is THE SINGLE BEST video/discussion of the uses, pros, and cons of the GH2's color profiles, the HACK, and data rates and GOP settings that I have ever seen.

WELL FRACKING DONE! - Extremely useful and helpful. 5-stars.

For me personally - what I take away from this is that increased data rates generally will make only a small improvement, but GOP-1 utterly changes the very nature of the footage in a manner that is only positive.
It seems that one's choice of color profiles can improve/hurt one's results more so than data rates with the GH2.
That's my take.
YMMV.

DPStewart
04-18-2012, 07:44 PM
...and nice V.O. editing - I don't think I heard you take a single breath! ;-)

mpgxsvcd
04-19-2012, 11:08 AM
Thanks for the compliments. You guys definitely got it. Super high bit rates is usually for bragging rights. GOP = 1 is sometimes very useful but usually used for the wrong reasons.

Now this test was done specifically to show that dynamic range was not affected at all by any of the settings changes. The color profiles definitely can affect the perceived dynamic range.

Standard and Natural were not included simply because their perceived dynamic range is less than that of Smooth. They simply have too much contrast applied to meet the dynamic range that smooth has. The Cinema setting actually is very good for showing shadow detail. However, it clips the highlights way too much to be useful.

Smooth is the only setting you should ever use if you plan on editing. If you are not going to edit then use the setting that matches your final output the closest.

I shoot all of the video first and then dub in the audio after I read it from a script. That way I can shoot the footage while the kids are playing around me and you want hear them at all. I edit out everything in between the clips so it flows seamlessly together. I shoot the audio in my car by simply holding the GH2 closer to my mouth than it normally is.

The clip below was one of my first efforts at it and you can hear how much I messed it up. I thought this video was one of my worst efforts but ironically it ended up with the most views. Youtube has a really fun way of promoting videos.

http://www.youtube.com/watch?v=J7q9nP0fKB4


http://www.youtube.com/watch?v=J7q9nP0fKB4

The GH2 mic is not great for audio. It isn’t bad for an internal mic though.