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View Full Version : aaaargh....matchmover and MAX


claytondouglas
11-01-2005, 08:11 PM
Hello all...



I am working as a post production artist at a firm in Orinda California. We are currently working on a project that involves footage from and Sony Z-1U, which is HDV 1080i (1080 by 1440). The softwares being used are Adobe Premier1.5 pro, Adobe After effects 6.5, Studio Max 8, Realviz Matchmover pro 3.1.



What we are trying to do involves a 3d Camera match.



My first question is this: What is the native raw specifications of this footage?

In order for it to work in Matchmover, It must be converted to frames(matchmover wont read the native codec) and it has to be exactly how the camera sees it or the optical distortion wont read correctly, and the match will be off.

What is the raw native aspect ratio? 4:3, or 16:9

What is the pixel aspect? .9, square, 1.333



I have tried all of the above mentioned options, and have gotten solves...but then that leads me to my next question



When I bring my solves into MAX...they move with the camera perfectly, but the cameras seem to be distorted differently.

The focal lengths recorded in MM and MAX are different fom each other too....meaning if in MM the focal length on a given frame has been solved as 43.1....then when its imported into MAX the focal length on that given frame is some other number. Is this normal?



Now since Matchmover doesnt export a distortion grid to anything but Shake, which we dont have at our disposal. Where do we go from here. We are very frustrated and aproaching a deadline that we are not going to be able to make if we cant get past this issue.



We cannot scale the model around the Matchmove, because everything is measured out and must stay so....so all we can do is translate in x and y(using z-up).



c

hiphopcr
11-01-2005, 09:13 PM
I don't know the answer to your question but why type in black?

claytondouglas
11-01-2005, 09:17 PM
I don't know the answer to your question but why type in black?


Is that even nessecary? If you ddont know then dont answer at all........

ronaldm
11-02-2005, 08:17 AM
Hello,

What you have to know is your exact pixel ratio. Then you should either directly set it in your camera attributes in MM or set up your filmback such that when you divide the film back ratio (film back width / film back height) by the image ratio ( 1440 / 1080 = 4 / 3 = 1.3333 in your case ), it gives the pixel ratio. For example, if your pixels were square (but it's not the case), you should input film back dimension with a ratio of 1.3333, which will lead to a pixel ratio of 1.0 (square)

The focal length should be the same one in MM and MAX. But you first need to check that the filmback is also the same.

For distortion, there's a tool called DistoIma that comes with MM that can be used to apply/remove distortion from footage that you can freely use.

Note that the new MM version exports directly the distortion grid in max.

Good luck

dprgb
11-02-2005, 03:09 PM
HDV Cameras do not have a square pixel aspect ratio: it's actually 1.333 The HDV 1080i format is defined as being a 1.85:1 (16x9) ratio overall image, taken at 1440x1080 pixels. For instance:

http://www.vasst.com/HDV/hdv-FAQnew.htm#HDVim

So, 1920/1440 = 1.33333333

If you just went to google and searched for 'hdv pixel aspect ratio' you would have found this out. You should probably do some more searches to learn more about the format and how to work with it properly.

Also, when rendering in Max make sure the pixel aspect is set up to match. When viewing in a viewport you'll also have to set up the background to match the rendered output, set up the rendered output to be 1440x1080 with a pixel aspect of 1.3333, and always view the image in the viewport with the safe frames turned on.

None of that will correct the distortion created by the max pinhole camera/real-world lens camera, but it will get you close.

claytondouglas
11-02-2005, 05:11 PM
Hello,

What you have to know is your exact pixel ratio. Then you should either directly set it in your camera attributes in MM or set up your filmback such that when you divide the film back ratio (film back width / film back height) by the image ratio ( 1440 / 1080 = 4 / 3 = 1.3333 in your case ), it gives the pixel ratio. For example, if your pixels were square (but it's not the case), you should input film back dimension with a ratio of 1.3333, which will lead to a pixel ratio of 1.0 (square)

The focal length should be the same one in MM and MAX. But you first need to check that the filmback is also the same.

For distortion, there's a tool called DistoIma that comes with MM that can be used to apply/remove distortion from footage that you can freely use.

Note that the new MM version exports directly the distortion grid in max.

Good luck


Thanks for the info....yeah were using mm3.1.....does that have that DistoIma tool...and if so where is it...Ive never seen it before?

claytondouglas
11-02-2005, 05:13 PM
HDV Cameras do not have a square pixel aspect ratio: it's actually 1.333 The HDV 1080i format is defined as being a 1.85:1 (16x9) ratio overall image, taken at 1440x1080 pixels. For instance:

http://www.vasst.com/HDV/hdv-FAQnew.htm#HDVim

So, 1920/1440 = 1.33333333

If you just went to google and searched for 'hdv pixel aspect ratio' you would have found this out. You should probably do some more searches to learn more about the format and how to work with it properly.

Also, when rendering in Max make sure the pixel aspect is set up to match. When viewing in a viewport you'll also have to set up the background to match the rendered output, set up the rendered output to be 1440x1080 with a pixel aspect of 1.3333, and always view the image in the viewport with the safe frames turned on.

None of that will correct the distortion created by the max pinhole camera/real-world lens camera, but it will get you close.

Yeah Im aware of the Google search thing...but as I said...Ive tried for solves using all of the above listed formats includint the correct one. I get a match....but once in max...the cameras dont appear to be the same...so I wanted to hear from some experts...FOR CERTAIN.

dprgb
11-02-2005, 06:36 PM
Well, the other post actually said something different earlier today (that you have square pixels and should use a 1.0 aspect ratio), he edited the post after I posted anyway.

Also, his math is incorrect. HDV has a pixel aspect ratio of 1.3333:1 to conform 1440x1080 to 1920x1080. The HDV format is 16x9... so the math should look like:

A=pixel aspect ratio

(1440*A)/1080 = 16/9 = 1920/1080

So, after good ol' cross multiplication you get:

(9*1440*A) = 16*1080

So A= (16*1080)/(9*1440) = 1.3333

I use Syntheyes, not matchmover, but I have no idea why you would end up with a square pixel aspect ratio - the filmback ratio is not 4:3 as measured in inches or millimeters, as the pixels are not square. The resulting recorded image is anamorphic as the pixels are not square. If you render the 1440x1080 to an intermediate 1920x1080 image, then you would have square pixels.

Maybe Matchmover works different than Syntheyes, but in Syntheyes I would just import the video at 1440x1080, with a pixel aspect ratio of 1.3333 since this is actually what the video is. It would make the match, I would export it (with the camera in SynthEyes set at a 35mm back to match the default 35mm back on the Max cameras) and that's it. Then, set up the max viewport to match rendering size of the background bitmap (the original footage), and view the camera viewport with the 'show safe frames' checked. It's always worked for me using .9 ratio NTSC images, the only difference between that and what you have is the pixel aspect ratio.

And sorry about the Google comment, it's just that so many questions get asked here that can be found in a 30 second search on Google.

ronaldm
11-02-2005, 07:35 PM
Hi,

So now you have your figures:
Your pixel ratio is 4/3=1.3333
Your image ratio is 1440/1080=4/3=1.3333
Your filmback ratio is 16/9 (something like 6.4x3.6mm),
(remember the formula pixel ratio = (filmback ratio / image ratio) )

Basically, you should just load your footage in MM and set the pixel ratio to 1.3333, and it will be fine (the exact size of the filmback is not important, only the ratio is).

I sent you a link for the distoima tool.

Bye

dprgb
11-02-2005, 07:41 PM
Also, incidentally, the Sony HDV cameras use pixel shift at the CCD - so the actual CCD is 960x1080 and not 1440x1080.

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