Get 9.5 Stops of dynamic range from your DVX100

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pertierr

Well-known member
Hello,

We have (finally) posted the results of a dynamic range test between the regular DV output from the DVX100A and the Andromeda uncompressed output from the same camera:

http://www.reel-stream.com/cap_comp

It took us a while because we ended up building a custom setup to do the most accurate test possible. The test setup involved a backlit Neutral Density scale chart, which allowed us to precisely measure the amount of light coming through each bar of the scale.

The two images correspond to the same frame, but recorded through the two different methods. The Andromeda output shows about 2.5 stops of extra dynamic range on top end. We adjusted the DV settings for the maximum possible dynamic range, but we should still be able to squeeze more dynamic range out of the Andromeda 4:4:4 output using different LUTs and 10-bit output.

Let me know if you have any questions.

Cheers,
Juan
 
I was initially skeptical, I must admit. I have to say, looking at it, it seems clear-cut that the Andromeda is indeed capturing and preserving over two stops more. That is an amazing accomplishment.
 
Partly it is because of limitations imposed by NTSC/PAL standards, but the largest factor is the fact that DV(and DVCPRO HD) handle only 8-bit color. The internal circuitry is free to assign the lowest value (0) and highest value(255) to any corresponding intensity of light, ~however~ there are limitations to what dynamic range you can squeeze into 8-bits and not have artifacts such as banding show up. It is highly dependent on what kind of curve you encode the raw 12-bit data with, and Andromeda allows the user to define those curves from scratch, so you get everything the camera really captures.

Hope this helps,
Juan
 
pertierr said:
Partly it is because of limitations imposed by NTSC/PAL standards, but the largest factor is the fact that DV(and DVCPRO HD) handle only 8-bit color. The internal circuitry is free to assign the lowest value (0) and highest value(255) to any corresponding intensity of light, ~however~ there are limitations to what dynamic range you can squeeze into 8-bits and not have artifacts such as banding show up. It is highly dependent on what kind of curve you encode the raw 12-bit data with, and Andromeda allows the user to define those curves from scratch, so you get everything the camera really captures.

Hope this helps,
Juan
Click to expand...

kind of, but how come we don't have this problem when hollywood films are encoded to DVD. Those are in 8bit too. How come we can still see a higher lattitude?
 
Well, you do loose dynamic range in the telecine process. But usually the telecine house chooses which parts of the dynamic range to discard and which part to keep. The same rules apply, the only difference is that you have a lot more raw, uncompressed information to begin with from the film scan, which is similar to the output Andromeda provides. From there, you can still go to 8-bits but it has the potential to look far better because whoever works with the footage can decide which aspects of the image to keep and which to discard during color-correction. Not to mention the limitations imposed by decimation, compression, etc.

When you're using the standard output from the camcorder, you're stuck with the look the camcorder gives it internally. You can change it a little in post, but not much. Once the data is decimated and compressed it's like rolling stuff uphill.

Let me know if you have any other questions.
Juan
 
Er... correct me if I am wrong, but that chart is a bit of a bad example.

The DVX's DSP will boost the gain when recording to DV and by the looks that chart is exposed for the uncompressed "no gain" output. This could account for the whites blowing out so much sooner. I don't know enough about the cameras DSP to really know, but all their examples seem to do similar misleading things.
 
Happy Halloween, Dr frankenstein !

9.5 fstops : just extraordinary.

Just an question, Juan : when you get data from CCD is it on 8 bits or more ?
 
The gain on the DVX is not a DSP function. It is wired directly to the A/D converters, so the gain switch affects both the Andromeda output and the DV output. This test was exposed for DV and we took no care with the Andromeda side specifically to make it as unbiased as possible. Indeed this is a "best case scenario" as far as the DV dynamic range, and a worst-case for the Andromeda side.

If you're not convinced, I can easily point out in the DVX100 schematic how the gain is wired. But please don't label this as misleading if you do not know how it works.

Cheers,
Juan
 
I'm missing something. What is Andromeda? Software? Hardware with software? I've found a company that has a plugin for photoshop but can't see how this would apply.
 
is it me or do the top three white tiles on the Andromeda stream look Greenish? perhaps its pushing the limits of the chipset?

maybe my monitor is off.....
 
Wow, thats beautiful.

How difficult is it to use? it seems like the workflow is convoluted.
 
To answer your questions:

The Andromeda image(and the DV image) are not color corrected, and where shot with a standard logarithmic (Cineon) LUT. This is one of the reasons why the white bars don't look white on the Andromeda side. Normally, when shooting for Andromeda one would adjust white balance for the uncompressed footage(not DV), and likewise adjust the LUT for the scene.

However, because we wanted to make sure we fully exploit what the DV side could do, we adjusted all the settings(including WB) for the DV side in order to yield the maximum dynamic range on the DV side, regardless of the fact that it would actually reduce the dynamic range on the Andromeda side.

Thus, this is what i mean by it being a 'worst case' scenario as far as the Andromeda side, but it is a 'best case' scenario for the DV side.

All the info for the Andromeda + DVX100 system is on our website:

www.reel-stream.com

But i will be happy to answer any other questions you might have.

Cheers,
Juan
 
I Read: "Allows for HD output up to 1540x990 from the DVX100 by utilizing the pixel shift between the CCD's. "
http://www.reel-stream.com/andromeda

Does this mean Hard Disk output or are you talking High Definition output??

And since this is not compressed video then instead of 13GB's per hour we are talking about 50+GB's?? (This images look fantastic... I'm just trying to figure out the real world applicability of this)
 
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