GH2 I love my GH2 + Driftwood hack!!!

Jaime Valles

Jaime Valles

Veteran
Just wanted to share that I'm blown away by this little camera. The GH2 + Driftwood's hack is amazing.
I'm attaching two frame grabs from a short test I made a couple of days ago.
The first is the original, untouched image, and the second has a bit of color grading and a wee bit of sharpening added.
Here is my workflow for this:

GH2 + Driftwood hack (Orion V2b)
24H @ 1080p24
Nostalgic (-2, -2, 0, -2)
ISO 160
1/50 shutter
Canon FD 50mm f/1.4 (aperture wide open)
Tiffen 0.9 ND screw-on filter
Available light only

Used 5DtoRGB to create ProRes HQ 4:2:2 files (ITU-R BT.709, Gamma 1.8).
Opened ProRes file in Premiere Pro CS5.5 (adjusted contrast, unsharp mask and used fast color correct).
Exported TIFF files and converted them to PNG in Photoshop for ImageShack upload.

Not a hint of aliasing or moire, and I can't find any macroblocking anywhere.
I love the fine grain-like image, and find the gradability and detail amazing. I wanted to give it a golden warm tone.
Obviously, one can get better results using a proper color grading app (Resolve, Magic Bullet, etc.)
but I just wanted to do this quick test and post it here right away. And, yeah, that's my ugly mug you're staring at. :)
Thanks to Vitaly for the groundbreaking hack, Driftwood for the amazing patch, and Kholi for the 5DtoRGB workflow tips!

Here's the original still:


And here's the graded still:
 
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And speaking of color grading, I'm kind of a noob at it. If any of you would like to take a stab at grading the original image (just right-click on the still and "Save As" or "Save Image As...") and post your method for grading here, I'd greatly appreciate it!
 
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Why use 5DtoRGB to create ProRes HQ 4:2:2 files before going into PP? Why not straight to PP? Is there some advantage to this extra step? Is the original still you've posted before or after creating the ProRes HQ? If it's after, would you mind posting another still straight out from the camera? I'm wondering what the same still would look like going straight into PP.

Thanks!
 
keylight said:
Why use 5DtoRGB to create ProRes HQ 4:2:2 files before going into PP?
Why not straight to PP? Is there some advantage to this extra step?
Is the original still you've posted before or after creating the ProRes HQ? If it's after,
would you mind posting another still straight out from the camera? I'm wondering
what the same still would look like going straight into PP.

Thanks!
Click to expand...
It's mostly about the gamma. The 5DtoRGB preserves the original gamma, which makes for a flatter, less contrasty image,
which means there's more info to play around with in post. Here's the link to Kholi's explanation of what 5DtoRGB does:
http://www.campcomet.com/archives/836

And here's the untouched, straight-from-camera MTS still image opened directly in Premiere Pro.
Notice how much more contrast it has over the original still I posted.

 
The downsides to the 5DtoRGB workflow are time and space. It takes quite a long time to process the footage, and the ProRes files it creates are significantly larger than the native MTS files. But what you lose in speed and hard drive space you gain in color and contrast accuracy. For quick turnaround jobs it's definitely not the way to go, but if you have the time, IMHO it's well worth the conversion.
 
I'll give it a stab on my non-calibrated monitor.

5hJbe.jpg
 
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Nice! Has a sort of dream-like quality to it. What software did you use for coloring?

And, yeah, I don't have a color-calibrated monitor either. Just a cheap Acer 21" P215h LCD monitor. Someday I'll have an HP DreamColor monitor...
 
I used Magic Bullet Looks for this. A lot of people don't like it because the presets suck, but if you use the tools from scratch you can get some awesome results.
 
If you're using Premiere Pro CS5/CS5.5, there isn't a reason to transcode. The gamma isn't going to be a problem because the files are .MTS, not .MOV, and so the QuickTime gamma issue doesn't come into play. Further, Premiere utilizes 32-bit color space to work with when using it's own toolset for color correction. And, finally, you're not shooting flat in the camera, so nothing 5DtoRGB does will bring back any additional information, just for grading purposes in post, so you're not really gaining anything.

For FCP7, 5DtoRGB is great. For a modern NLE like Premiere, it's unnecessary and wastes disk space.
 
Gary Huff said:
If you're using Premiere Pro CS5/CS5.5, there isn't a reason to transcode. The gamma isn't going to be a problem because the files are .MTS, not .MOV, and so the QuickTime gamma issue doesn't come into play. Further, Premiere utilizes 32-bit color space to work with when using it's own toolset for color correction. And, finally, you're not shooting flat in the camera, so nothing 5DtoRGB does will bring back any additional information, just for grading purposes in post, so you're not really gaining anything.

For FCP7, 5DtoRGB is great. For a modern NLE like Premiere, it's unnecessary and wastes disk space.
Click to expand...
But there *is* a difference. Here's the 5DtoRGB file next to the MTS file:

 
There's only ONE thing to consider, but hasn't been investigated it seemed like. I can't explain it, but here are posts from another thread concerning similar questions:

PDR said:
Minor clarification: DPX=> DPX is lossless, but AVCHD => DPX actually isn't lossless. Y'CbCr and RGB are non-overlapping color models, and there are out of gamut colors when converting to RGB. Even a "full range" conversion done in 5DtoRGB or other programs isn't lossless, there are out of range values not mapped to RGB color model. But the point is moot if you are using AE, because AE converts to , and works in, RGB internally anyway (or rather BGRA). Even a wide gamut RGB workspace cannot contain all potential values of Y'CbCr.

The "science and theory" is the difference in the chroma upsampling algorithm used in other programs. AE uses a nearest neighbor algorithm, leading to "blockier" colors. Well some people say: just blur the chroma before you key - It won't produce the same results, because the chroma isn't blurred in the first place when using the other methods. On the contrary - it's actually sharpened when using something like a lanczos or spline36 algorithm.

To understand what's going on, look at comparisons of various upsampling algorithms eg. spline, lanczos, bicubic , mitchell, etc.... In a 4:2:0 1920x1080 video , CbCr are actually 960x540 resolution, but Y' has 1920x1080 resolution. Try upscaling any RGB image to a larger dimension using one of the algorithms and you will see the difference - this is analogous to what is happening to the color information in CbCr upscaling during the RGB conversion.
Click to expand...

PDR said:
That's the theory. In practice , it's not a big difference (you're not leaving that much on the table)

The reason is most AV hardware do not take full advantage of what Y'CbCr can store by the time it gets recorded to card , either the sensor , or internal processing (and not just the GH2). Most of the time a full range conversion to RGB will contain the majority of the usable data under normal controlled shooting conditions. But under abnormal conditions, maybe colored lighting, overexposure - there can be usable values lost because of converting to RGB

Similarly, the method of pre and post treatment for keying 4:2:0 footage directly can deliver similar results if done correctly. The difference might be minimal with a skilled VFX artist. People have to ask themselves if it's worth it for their purposes and goals
Click to expand...


PDR said:
I don't know which one 5DtoRGB uses, but it's clearly not "nearest neighbor". Most likely it's bicubic, it seems some of the software - like the prores conversion - is based on ffmpeg code. You can ask or PM Thomas Worth if you want details. But maybe sometimes you want nearest neighbor, or mitchell, x,y,z algorithm (they all have pros/cons - for example lanczos4 can produce aliasing and oversharpening) - but the point is you have no control over that in AE, and it defaults to (probably) the worst algorithm. Even photoshop will use bicubic as default for resizing.




Yes, but see the previous comment on "in practice" and actual usable information. But the facts are clear on the science side - all values of RGB are represented by Y'CbCr color model, but the reverse is not true.
Click to expand...

PDR said:
Yes, Y'CbCr has wider range of values than RGB .

If you're a "math" guy and like equations and models, scroll down to the middle of this page, and look at how the RGB "cube" is fully contained within the Y'CbCr "cube"
http://software.intel.com/sites/products/documentation/hpc/ipp/ippi/ippi_ch6/ch6_color_models.html

But it's the choice of method of RGB conversion (not just the upsampling algorithm) that can cause differences, and the associated actual math equations defining those models that limit Y'CbCr=> RGB conversions. For example a Rec709 conversion will be different than a Rec601 or Rec1361 conversion to RGB.

But the fact is just about everything else works in RGB - compositing programs, our displays and monitors, equipment , still photos, etc... We live in a RGB world. (yes, LAB and CMYK, but RGB is predominant by far)



MPE doesn't affect AE.

Premiere is a different story. It has "YUV" labelled filters that can access YUV (YUV is analogous term to Y'CbCr), but internally it still works in RGB (actually BGRA)
Click to expand...

And if you're interested in the conversation, regarding 5DtoRGB for GH2 footage and keying/greenscreen, here it is:http://www.dvxuser.com/V6/showthread.php?273276-Is-there-a-reason-to-use-5DtoRGb-on-Windows

So until someone with more experience and knowledge fully investigates, I wouldn't rule out 5DtoRGB actually helping.

On another note, I'd suggest anyone using it look into batch if you're on Mac. Not sure where the windows version is at currently.
 
Jaime Valles said:
But there *is* a difference.
Click to expand...

What Gary's saying is that in Premiere, you could adjust the gamma and end up with the same results. Whether they're the exact same (or which would be better) doesn't seem to be completely understood, but if you're working in Premiere you could do that and see where you end up.
 
Kholi said:
What Gary's saying is that in Premiere, you could adjust the gamma and end up with the same results. Whether they're the exact same (or which would be better) doesn't seem to be completely understood, but if you're working in Premiere you could do that and see where you end up.
Click to expand...
Ah, I see. Hmm... it definitely requires further exploration.
 
Jaime Valles said:
And it's not just the gamma that's fixed with 5DtoRGB. Here you can see the smoother chroma as well:
http://rarevision.com/5dtorgb/comparison/
Click to expand...

That's the other thing that 5DtoRGB helps with, and you can definitely see that by comparing as they did.

Honestly, I don't see a reason not to use 5DtoRGB. I'm not gonna go through every clip and adjust gamma, or drop a filter that does it on a timeline. Forget that. Being able to kick out DPX or PR4444 is great. 5DtoRGB does plenty enough to justify the cost.

Right now it's more so deciding whether to spit out 4444 and get rid of the AVCHD stuff, or keep the AVCHD, export proxy from 5DtoRGB and return to the AVCHD for DPX to color with.
 
One big reason not to use 5DtoRGB if you're on Premiere? Since both DNxHD and ProRes are wrapped in QuickTime containers, it means performance will suffer in Premiere vs. the native .MTS file.
 
Jaime Valles said:
And it's not just the gamma that's fixed with 5DtoRGB. Here you can see the smoother chroma as well:
http://rarevision.com/5dtorgb/comparison/
Click to expand...

That is comparing the difference between different ProRes transcoders (FCP/Canon E1 Plugin vs 5DtoRGB). It is not making any comparison to the original source material. If an NLE properly interprets the MTS file without transcoding, then results could be very different.

The best thing to do would be to compare the color channels of the original MTS file and the transcoded file in PPro to see if there is any benefit to be gained from transcoding.
 
Gary Huff said:
If you're using Premiere Pro CS5/CS5.5, there isn't a reason to transcode. The gamma isn't going to be a problem because the files are .MTS, not .MOV, and so the QuickTime gamma issue doesn't come into play. Further, Premiere utilizes 32-bit color space to work with when using it's own toolset for color correction. And, finally, you're not shooting flat in the camera, so nothing 5DtoRGB does will bring back any additional information, just for grading purposes in post, so you're not really gaining anything.

For FCP7, 5DtoRGB is great. For a modern NLE like Premiere, it's unnecessary and wastes disk space.
Click to expand...

See, this is what I was thinking. I couldn't understand why you would need/want to go to ProRes if you're cutting in Premiere. I do see the benefit if you're cutting in FCP.

Anyway, it's an interesting thread, that's for sure.
 
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