Stereo3D Preview output from camcorders
 

I would like to preview the video in 3d during capture, or just before that (check the final camera alignment, window violations, etc. I am considering to use NTSC composite video as it is available from my Sony camcorders via the A/V connector, digitize it, most likely with USB dongles connected to netbook PC and either diplay it as an anaglyph, or output it 50% compressed into stereoscopic glasses, using Peter Wimmer's 3dtv software. AVCHD outputs are available as well, but I would guess that route would be lot more difficult. I know some people are doing it, and I am asking for practical and tried solutions for actual Hardware and Software. I would really appreciate your advice. Thank you, Pavel.

Some glasses is not available that have two input, and show the left camera picture to the left eye, and the right to the right?

I am not sure. There are two sources of glasses that will do that that I found (Zeiss and Vuzix). The video for those glasses must be processed for a side-by-side 50% squeeze, so it must be first digitized and processed, which unfortunately means that I have to have a computer between the cameras and the glasses, unless someone has some other way to process the two streams, or know of glasses that will accept two separate analog or digital streams. I was looking for suggestions from someone who actually did it. I think that once I have a computer in the rig, I prefer to use it's screen and display an anaglyph (and possibly differential) preview on a small netbook PC rather than using the glasses, even though once I have the digitizer and netbook PC, I should be able to do it either way.

I am not sure about this. I have only seen one product that seems to be designed for something like that, the Black Magic Design HDLink Pro 3D, it is not quite clear from its description how exactly it works. Additionally, instead of using the standard HDMI output they have chosen something called DisplayPort, so you need another adapter to convert that to HDMI.

Thanks Adam. This would be actually a cool device, unfortunately it only takes in SDI, which I don't have available. The output is not a problem, because it has a DVI-D, an it as well as the dual variety of the DisplayPort can be passively converted to HDMI, which many monitors feature at their inputs. The only outputs my camcorders have are HDMI and SD analog composite or component, so I have been looking into digitizing the analog outputs, running it through the Stereoscopic Multiplexer and Stereoscopic Player on a NetBook, and drive it's screen, or just the Multiplexer to drive glasses. It is generally difficult for computers to digest HDMI streams, specially a pair of them, so at least for now I am thinking about the above method, unless I find something that doesn't require a computer. Of course two HDMI displays are an option, but the bulk, power and alignment seem too much trouble. Your suggestion is very close, except for the input port flavor. Thanks though.

Well, depending on your budget, the same company (Black Magic Design) makes HDMI to SDI miniconverters. They also make analog to SDI miniconverters, though I would go for the HDMI ones if your cameras support it because HDMI is digital from the getgo, so you have no loss of quality in the conversion.

I own one of those HDMI to SDI miniconverters, and they are very well designed.

Thanks, I have to look into it.

well if you got 2 camcorders close enough, it means you can have the viewfinders close enough too.
Problem is many small camcorders are coming without viewfinder (like mine).
the you can get the composite out, and feed some dual lcd glasses (like some HUDs are).
or build a device that take both composite signals, and alternate each side on a monitor.
you can use any cheap lcd glasses (wired or not) to see in 3d.
I purchased the composite synchroniser from colorado-video few months ago, but had no time to test it yet.
it is supposed to take 2 unsynch composite video in and give them back as synchronized out. (in real only one signal is synchronized on the other, but the result is the same).
it cost 700$ but if it works you can build a stereoscopic monitoring system that fits any camera.
I still have to build the stereoscopic mixer (a simple sync extractor that can be build from a 5$ chip).
The fact is the board (MLVXP-01 from Millogic) that process the signal could easily manage to deliver alternate field or frame (frame is better because it will work with any LCD screen, while filed would work only with obsolete CRT), but unfortunately i got no way to change the program inside.
I think that if colorado-video can sell the board for 700$, it must cost cheaper directly from millogic, and with proper programming you would get nothing to do other than connecting a screen on one output, and the glasses to the other output.

Great ideas. As far as the viewfinder proximity, unfortunately they are little too wide for my eyes, because of the drives. I ended up building an arrangement that I am showing in the following sites: YouTube - Articulated Amateur 3D Rig Experiment - Part 2 Partially Red & Cyan 3D HD Anaglyph , YouTube - Articulated Amateur 3D Rig Experiment - Part 1 , , . Not as good as some of your other suggestions, but was easier for me to do (and cheaper). I will look into the other suggestions in the future, and thank you all for your helpful suggestions.

Pavel, a very good nd interesting video clip of how to get anaglyth on your laptop.

Now this has got me thinking. With all this Shanzai gear showing up for very low prices, I am wondering if there's a small 7 inch tablet running windows which can be used as a smal monitor. In fact I am sure I saw something the other day which runs Windows CE.

If the Stereoscopic Muliplexer can run on Windows CE or android ( highly doubtful) we could have very cheap and simple solution in our hands.

Something along the lines of this is what I was thinking of. Not sure where they are available from to order one to test. Also I would have to make a bracket to attach to the camera. That should be easy to do though.

http://www.shanzai.com/index.php/ban...sirf-prima-soc

Cheers
Steve

OK I have ordered up the same dongles ( easycap) and cables. Should be with me this week.

I note that the capture device/viewer has to have two seperate usb's and you can't share a single usb slot.

I am wondering whether a USB2 OTG and USB host 1.1 will be OK as the two.

So using one of those cheap Shanzai 5 or 7 inch tablets running Windows CE means that the whole system is portable. I will have to trace a tablet with two USB ports but they are out there and they are cheap.

I received several valuable suggestions on this forum and seriously considered them all. I ended up choosing the method I described just because it was most available and practical for me from technology readiness, financial and other aspects. I will feel very differently about this in the future, I am sure. Some of the items suggested are not available yet, some, like the tablets, (I considered iPad, Dell and couple of others) didn't have the right ports and S/W capabilities, even though the displays, battery life and the form factors are marvelous. Among others I also considered couple of small side-by-side monitors and optical viewer rig - no computer or S/W. I would like to have minimum bulkiness, portability and free hands so that I can operate Steadicam, so the current solution seemed the most implementable option together with the Vuzix glasses, which I didn't show yet, but they work really great for my purpose.

The main problem I have at the moment is how to carry the notebook and how to control it. I was thinking of some sort of backpack (or frontpack) with good ventilation, where I could carry the computer while moving. Another issue is how to control it, so I have to find some sort of super compact keyboard/keypad to put the PC to sleep and to wake it up. I don't want burn the battery too fast. I am currently considering to use the computer display just for initial alignment before capture session, and would be using the Wrap 920 as a viewfinder - the resolution is too low. I have been using the left camcorder viewfinder for framing so far, but that method has several serious drawbacks. I have hard time to see the LCD in a bright sunlight, which is plentiful here in Southern California. I also got into trouble several times in guessing what the right camcorder is seeing, and ended up with serious stereoscopic window violations on the extreme right.

Please keep providing the ideas and suggestions, because as technologies and experiences evolve, I am sure there will be much better solutions than this one. I had to pick one for now though.

Pavel, there are definately 7 inch tablets running windows with two USB2 ports. It would be easy to make a mount to fit on the camera as a monitor.

There is an iPad clone called the ePad which has two USB2 ports. Its 10 inches so a bit large but would certainly do the job. I am sure with a littlw more lookiing there's a 7 inch version with 2 USB2 ports ot there. Then there would be no need at all for bulky, heavy laptops.
Here's one that would work but 10 inch screen.

NEW 10.1"EPAD MULTI TOUCH SCREEN PC TABLET EMS SHIPPING on eBay (end time 27-Jul-10 07:49:56 BST)

I just wanted to chime in and say a big THANK YOU to all of you who are contributing to this thread. It is extremely interesting and informative for me personally. I have been trying to find a low-cost method of monitoring on set, and have considered a variety of methods.

I purchased two of these LCD monitors ( 7" LCD Monitor ) and mounted them in a box with a beamsplitter mirror between them. It works okay, but getting them aligned perfectly is a chore, and the alignment depends on the viewing angle.

Monitoring on a single screen via software-mixing of video feeds seems like the best way to go.

A friend also pointed out software called "Max/Jitter" (Max - Cycling 74) which seems like an option, but would require some programming.

I am now going to study all of the links and videos posted above, because I think you guys are really on to something here!

Thank you so much for sharing, and I hope that you will continue to post your experiences.

--Drew