Somewhat dumb question about Cineform
 

I've been looking at the Cineform website and as I understand it (maybe wrongly!) I can capture over firewire and go to Cineform 4,2,2.

But I thought that the data stream from the camera was in 4,2,0.

So I'm confused about how one goes from 4,2,0 to 2,2,2. Is there sufficient information remaining in the 4,2,0 stream?

I also see that cameras will upres from 4,2,0 to 4,2,2 so I guess I'm equally confused about how this is possible and how much if any different it is from native 4,2,2.

Jim,

My understanding is that it upconverts/trancodes the footage to an AVI in the 4:2:2 colorspace. This does not add quality on capture but will give you better results when you start color correcting, compositing etc.. This is because you're now rendering your effects in a higher quality color space so they are less likely to break down like a DV or HDV codec would when pushed to it's limits. I should note that you also go from about 12 gb (HDV) to 38 gb (Cineform) per hour of footage.

You will want to use the "High" or "Film Scan" setting when capturing to Cineform for best results. I've heard on this forum that "Med" or lower will look slightly soft.

Regards,

Marc

Marc,

Thanks for the comeback.

So if I understand correctly, there is no improvement over what was already captured, but there should be less "generational loss" down the road because any additional changes etc to the video will be done in a higher quality color space.

In other words, the 4,2,0 space is in some way a subset of the 4,2,2 space so the original video just sits there like it was in the beginning with no additional information being inferred or interpolated and addtional edits have more - shall we say "headroom" than they would have had if left in 4,2,0.

The same concept would apply to the 10bit of Prospect vs the 8bit of Aspect?

4:2:0 to 4:2:2 (and 4:4:4) upconverting filters are required for NLE, compositor and 4:2:2 display technology. While there is no new chroma information, there is a visual quality improvement for doing filtered 4:2:0 to 4:2:2. see http://www.cineform.com/technology/H...ysis051011.htm We could perform this opteration on decode, but instead we do it before we encode into CineForm. Do the upconvert before compression, improves the chroma channels quality through compression.

The same goes for 8-bit up conversion to 10-bit. While there is no new information in the upconverted 10-bit, it goes through the compression with improved precision for downstream reconstruction, greatly reducing the banding often associated with compressed 8-bit.

Pardon me for the very simply metaphor but it is somewhat descriptive....

When you shoot HDV which is highly compressed at 8 bits and 4:2:0 color space, you have little ability to "move" the image in post. Think of it like filling a bucket to the top with water, and then somebody telling you to carry the bucket 100 yards up a rock-strewn hill without spilling a drop.

When you use CineForm, before you "move the bucket up the hill", we give you a much bigger bucket - about 3X bigger in the case of HDV. So you dump your original full-to-the-top bucket ("HDV") into our 3X larger bucket ("CineForm Intermediate") then carry it up the hill. Because the bucket is so large you haven't lost any water.

The association here is that our files are larger, but they create much more headroom to allow you to "move" your images in post in a similar manner to a larger bucket making it easier to move water up the rock-strewn hill without spilling a drop.

I just upgraded from NEO HDV to NEO HD and I was wondering since I shoot HDV can I up my output to 1920x1080 vs the HDV 1440x1080 and work in a HD timeline in my NLE (vegas 8) and output it out as HD 1920 on a blu-ray burner?

Cary,

Yes to can upconvert to 1920 when capturing 1440 HDV content.

Question --

What do you recommend, regarding the colorspace issue and color correcting? Currently, I capture .m2t files, color correct and then render out with CineForm. Am I to understand, based on this thread, that it is better to FIRST render out a CineForm .avi BEFORE any color correction?

Thanks.

It is a tricky subject. In an ideal world an 8-bit sources could be decoded to a deeper format (16-bit integer or 32-bit float), color corrected and sent to a deeper format like CineForm to preserve the quality (and it work fine that way in AE.) However, when render from non-CineForm files with Premiere we can't assume it can handle 32-bit float, so we only request 8-bit RGB. If you convert first, this problem goes away, as we can decode to 32-bit float, allowing for much nicer color correction.

David when you say " convert first " are you talking about converting in
AE first and then bringing the converted footage into Premier??

What are talking about, I've lost track? My last answer was regarding converting M2T data to CineForm before your edit/CC.

The way I read the answer was that in AE you'd get great results by taking native source in and color correcting before outputting to Cineform, but this wouldn't always be the case for other applications, like Premiere, so in general it would be best to go to Cineform right away.

Of course, this was just my interpretation, so I'll wait for the definitive answer.

Yes. Try working native M2T in AE and you find the other reason to convert to CineForm first -- speed.