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Permalink Reply by Vernon Barry on May 20, 2012 at 6:15am

It works with ANY APM that outputs telemetry in MAVLINK format. I could see how that's not 100 percent clear from the pages I linked but that is the difference (getting back to the original question in the thread )between minimOSD and Remzibi's OSD. The Remzibi's OSD board is more ore less standalone in that you attach sensor and GPS to that board, where the minimOSD uses the data coming out of the APM on the telemetry port so that you don't need duplicate sensors. In other words, let's say I have a FPV plane or heli that I do not use an APM 1.0 or 2.0 and just fly it with normal radio control and obviously have a video cam system (either recorded or downlinked to the ground via radio) but I want to see in the video, telemetry data(GPS, temperature, altitude, speed. etc..), then the Remzibi is the correct choice because I do not have an APM. But, if you do fly APM 1.0 or APM 2.0, then just use the minimOSD and connect to the telemetry port. Further, I want to add something not stated in the directions but has been said before. You can put the OSD board at the ground station via the Xbees or new 3DR radios and send down pure video from the camera to the ground (no OSD in that feed) and then ADD the OSD info at the ground. Here's why you might want to do that. If you want to post the videos say online or show your buddies, recording a version minus OSD might be nice, but then you could still display OSD on the screen or video glasses you actually fly with or even on a separate recorder get a version with OSD. The key here is think of the Wireless telemetry radios as a wire. Basically at either end of the wire, you are plugged into the APM telemetry port. Either end of tht wire is still connected to the APM telemetry port. All the minimOSD needs is that data.

The directions are here:http://code.google.com/p/arducam-osd/wiki/minimosd

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3D RoboticsPermalink Reply by Chris Anderson on May 20, 2012 at 6:38am

Yes, MinimOSD works great with APM 2. Just connect it to the telecom port, like you do with APM 1. Instructions are here. 

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Permalink Reply by Jake Stew on May 20, 2012 at 2:49pm

Are there any color OSDs out there?  I always thought the monochrome was just way too lame to bother investing in it.

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Permalink Reply by Vernon Barry on May 20, 2012 at 11:49pm

EDIT:   I take that back, more searching led to this chip http://www.i-chips.com/page/ip00c502

Not exactly a ready made product but it appears from the specs to do what you asked.

 

http://www.rcgroups.com/forums/showthread.php?t=1145366

Some of the technical hurdles to overcome are the fact that you are taking an existing video signal and trying to overlay an image. Due to the structure of the NTSC or PAL signal which are both backwards compatible to black and white, the color is much trickier because it's added in. The only good way to do it is to capture the entire video feed from the camera and digitize it, then use a computer to do a video overlay function. Basically, it takes way more horsepower than any single chip can provide.

Key words like genlocking http://en.wikipedia.org/wiki/Genlock

Chrominance http://en.wikipedia.org/wiki/Chrominance

The presence of chrominance in a video signal is indicated by a color burst signal transmitted on the back porch, just after horizontal synchronization and before each line of video starts. ... In NTSC and PAL, hue is represented by a phase shift of the chrominance signal relative to the color burst,

vau Registered User UK Joined Jan 2007 247 Posts

I'm with andology, this is a mock-up. there are no colour genlock chips out there right now that could deliver the quality in the screenshot. Easy enough to generate the colour display, but to do so whilst genlocking onto a composite (or RGB for that matter) signal is not practical (possible) on any IC I know of. On the subject of transparency though, it doesn't matter what your colour depth is as long as at least one bit is used as the alpha channel. Probably more practical to digitise the analogue video, overlay the OSD and then output composite again for transmission. I wanted to do this with a gumstix like device a while ago but apathy got the better of me (again.) vau Registered User UK Joined Jan 2007 247 Posts I'm with andology, this is a mock-up. there are no colour genlock chips out there right now that could deliver the quality in the screenshot. Easy enough to generate the colour display, but to do so whilst genlocking onto a composite (or RGB for that matter) signal is not practical (possible) on any IC I know of. On the subject of transparency though, it doesn't matter what your colour depth is as long as at least one bit is used as the alpha channel. Probably more practical to digitise the analogue video, overlay the OSD and then output composite again for transmission. I wanted to do this with a gumstix like device a while ago but apathy got the better of me (again.)

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Permalink Reply by Vernon Barry on May 21, 2012 at 12:32am

Further searching came up that Xilinx has the "program" to drop onto one of their FPGA chips (or at least that's what I think they are saying). I know it's not a program, but rather the setup for the logic gate array, but to somebody just trying to build a simple OSD, in theory you buy the chip and then buy this IP, and burn the chip with it. http://www.xilinx.com/products/intellectual-property/EF-DI-OSD.htm 

The difference between this in the i-chip, is that you might have a chance to get an FPGA eval board and then maybe get this burned on it. The i-chip looks like you might be locked into some serious cost, even just to evaluate one. Anybody showing they sell to government and pro video solutions isn't cheap, and likely wants volume and a support engineering contract.

Actually, discovered the policy for Xilinx:

Note

The evaluation core will cease to function in a programmed FPGA device after a period of time. See the Requirements page for this core for information on the duration of this time period.

So yes, in theory, you could eval the "bitstream" to in theory set up a color OSD using an FPGA, and then you would probably still need an Arduino to do the code bit, unless you felt like purging that to FPGA as well. In other words, the arduino works just like minimOSD, but then the FPGA does the actual genlock, and overlays the color text or graphics over the video feed.

I had a single class on FPGA that was all theory and no hands on. We designed a 7segement decoder, so this is about a million times more complicated. The reason why you can't do this in say an Arduino is the speed required to get the timing and phase right in the genlock. You can do simple B/W OSD with an Arduino, but most solutions use a hardware chip for speed and acurracy to do the genlock, and even then, due to the phase complexity of color burst, they just do black and white or greyscale. It looks like i-chips is the only single chip solution that might do what you want, but I don't even see a good way to get the chip unless they give you a sample. They just seem like the type of company that would charge you an arm and a leg just to do that. I could be wrong though.

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Permalink Reply by Jake Stew on May 21, 2012 at 9:12am

Thanks for the links Vernon.  An 8-bit uC can generate old video game quality color.  There are a few projects that use PICs and other uCs as video game systems.

So the real issue is the timing and mixing since, like you said, there isn't enough power to digitize, mix, and output video.  But there has to be a simple video mixer chip out there.  Fading, mixing, and overlaying are very common video tasks.  I looked around a year or two ago and didn't find any real easy solution, but there has to be something out there which does something as simple as mixing two video signals!

Perhaps the uC could even do the task.  If your code was good I would think you could use the video timing as an interrupt and inject your signal at the right point in the scan?

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