PDA

View Full Version : GH2 Will be shooting a slow-mo shot with the GH2... should I use 720p 60 or 1080i 60?



Filmkid2003
12-11-2011, 03:26 PM
Hey everyone. First of all, the rest of the film is shot with a GH13 and GH2 at 1080p 24. I will be shooting a few shots in slow motion, with the GH2 on a tripod, of the actor walking towards the camera. Since the rest of the film is shot at 24 frames per second at 1/50th shutter, should I shoot the slow motion shots at 720p 60 with a shutter speed of 1/125th and then upres the clip to 1080p 24 or should I just shoot it at 1080i 60 with a shutter speed of 1/125th and not have to upres the clip but deinterlace it? Can someone please help me? Thanks.

Ralph B
12-11-2011, 06:07 PM
I recommend that you do some tests and try it both ways. The 1080 60i has the potential to look better than the 720 60P if you use a high quality, adaptive de-interlacer. However, if you use a deinterlacer that simply throws away one field, then the 720 60P will look better. In short, it's all dependent on the quality of the de-interlacer.

Filmkid2003
12-11-2011, 06:14 PM
Thanks, Ralph. What high quality deinterlacing software do you suggest I use?

Sage
12-11-2011, 06:33 PM
On the Gh2, 60i taps into a far superior sensor scaling. The detail is considerably more, and the color space is much richer.
The 60i seems to play nicely with the spatial (horizontal/vertical) resolution distribution of the gh2 1080 scaling as well. And this is just using the pure frame data captured (half vertical resolution).

If Gh2 720 scaling was on the level with 1080, this would be another consideration:
1920x540=1036800
1280x720=921600

Filmkid2003
12-11-2011, 10:38 PM
Thanks for the help. Unfortunately, I already shot some slo-mo footage at 720p/60. Is there any way for me to upres the footage to match the 1080p/24 footage without any adverse effects like noticeable softness? What is the best software for upresing 720p to 1080p?

Ralph B
12-12-2011, 12:28 PM
Thanks, Ralph. What high quality deinterlacing software do you suggest I use?

My personal favorite deinterlacer is Yadif which I run in an Avisynth script. If you're interested, I'll provide more details.

mpgxsvcd
12-12-2011, 02:09 PM
Thanks for the help. Unfortunately, I already shot some slo-mo footage at 720p/60. Is there any way for me to upres the footage to match the 1080p/24 footage without any adverse effects like noticeable softness? What is the best software for upresing 720p to 1080p?

In reality 720p actually has about the same resolvable resolution as properly deinterlaced 1080i. 1920x1080 does not contain 1920 resolvable horizontal lines. The GH2 1080p contains more like 900-950 resolvable horizontal lines.

And the 1080p resolvable vertical resolution is closer to 800-850 lines.

Therefore, going from 1920 to 1280 really isn’t helping you that much in horizontal resolution. You get about the same resolvable horizontal resolution for both. It is within 50-100 lines which really isn’t that big a difference.

When you go from 1080i with 1080 vertical lines to 720p with 720 vertical lines you actually get almost the same resolvable vertical resolution even with properly deinterlaced 1080i. It is about 650 lines for both.

With 1080p that vertical resolution jumps up closer to 800 lines. That is where you see the big difference in 1080p video vs. 720p video.

My opinion is that true 1080i/60 should never be used for anything with the GH2. The GH2’s 720p is superior to 1080i/60 in every aspect. I shot tons of slow motion video this weekend. All of it was 720p @ 60 FPS and you won’t be able to tell the difference between it and the 1080p @ 30 FPS video I shot at the same event.

If you simply stretch 720p @ 60 FPS to 40% playback speed it conform perfectly to a 1080p @ 24 FPS profile. I use to do that before the GH2 got 1080p @ 30 FPS. Now I just stretch it to 50%.

roei z
12-12-2011, 02:41 PM
In reality 720p actually has about the same resolvable resolution as properly deinterlaced 1080i. 1920x1080 does not contain 1920 resolvable horizontal lines. The GH2 1080p contains more like 900-950 resolvable horizontal lines.

And the 1080p resolvable vertical resolution is closer to 800-850 lines.

Therefore, going from 1920 to 1280 really isn’t helping you that much in horizontal resolution. You get about the same resolvable horizontal resolution for both. It is within 50-100 lines which really isn’t that big a difference.

When you go from 1080i with 1080 vertical lines to 720p with 720 vertical lines you actually get almost the same resolvable vertical resolution even with properly deinterlaced 1080i. It is about 650 lines for both.

With 1080p that vertical resolution jumps up closer to 800 lines. That is where you see the big difference in 1080p video vs. 720p video.

My opinion is that true 1080i/60 should never be used for anything with the GH2. The GH2’s 720p is superior to 1080i/60 in every aspect. I shot tons of slow motion video this weekend. All of it was 720p @ 60 FPS and you won’t be able to tell the difference between it and the 1080p @ 30 FPS video I shot at the same event.

If you simply stretch 720p @ 60 FPS to 40% playback speed it conform perfectly to a 1080p @ 24 FPS profile. I use to do that before the GH2 got 1080p @ 30 FPS. Now I just stretch it to 50%.

that's good to know-
thanks :)

Sage
12-12-2011, 03:55 PM
Don't take my word for it (that 1080i far outpaces 720) - just shoot both and compare.

I had a revelation this weekend. You could say a hard core progressive addict discovered the value of interlace.
I was developing the Gh2-x Quantum patch - and I started testing. The rest is history. The level of detail was a dream.

mpgxsvcd
12-12-2011, 07:20 PM
Don't take my word for it (that 1080i far outpaces 720) - just shoot both and compare.

I had a revelation this weekend. You could say a hard core progressive addict discovered the value of interlace.
I was developing the Gh2-x Quantum patch - and I started testing. The rest is history. The level of detail was a dream.

Try 1080p @ 30 FPS. That is a lot better than 1080i.

Filmkid2003
12-12-2011, 08:50 PM
Thanks, Ralph. Can you please provide more details about Yadif? M (http://www.dvxuser.com/V6/member.php?55577-mpgxsvcd)pgxsvcd, do you know of a good uprezing software that will give me clean results? By the way, I edit with Premiere Pro CS5.

Ralph B
12-13-2011, 12:57 AM
Here's a package of files that will get you going with Yadif. I've included Avisynth, Yadif plugin, Yadif script, VirtualDub, two codecs and a batch processing program.

Briefly: Install Avisynth. Put yadif.dll in the Avisynth plugin folder. Put the script "60i to 60P yadif.avs" inside the same folder as your 1080 60i MTS files. Open the script by double clicking it. Rplace __vid__ with the name of the clip you want to deinterlace. Quotes must be around the name. Example: "00001.mts" . Save the script. Drag and drop the script onto VirtualDub.exe. Virtualdub will open with the clip already deinterlaced. The framerate will be 59.94. Choose a codec from the menu: Video/Compression. Press F7 to render. Done.

If you want to automate this process, explore Batch Intermediate Creator. I recommed using VDub-BIC.

1080 60P can be challenging to playback smoothly. That's why I've included the Blackmagic MJPEG codec. Install it by running Intensity_3.3.1.msi. This will install the drivers for the Intensity board + all the Blackmagic codecs. You don't need to have an Intensity board for this to work. The MJPEG codec is very good at playing 1080 60P smoothly.
I've also included UT lossless video codec, if want the ultimate in quality, although it probably won't play smoothly.

http://www.sendspace.com/file/gniqyw

NOTE: Be careful when downloading from Sendspace. There are many buttons that say "download", but only click the line that says, "Click here to start download from sendspace".