GPS/Direction Overlay on Video?

doormat asks: "I've come up with a solution where I would need to overlay the current GPS location (Lat/Long) as well as the current direction onto a video stream. I've seen it on still cameras but not on video cameras. I've got the equipment for survey-grade GPS, I just need to put in onto the video frames, either in real-time or somehow in post-processing."

Comments

Re:Get a mixing desk then

[hey!]

I'm guessing he wants to do it in the field. That way the footage is combind with the GPS location and time at the moment it's recorded. There's a lot of interesting applications for this, such as recording animal behavior for scientific studies etc.

I don't know anything about video, but I do know quite a bit about GPS. GPS's universally send NMEA strings, which are essentially comma delimited 1 record per line data, the first field containing the class of data being sent. They all send various kinds of status information, such as the current fix, last good fix, satellite strength etc. Some makes, such as Garmin, have their own proprietary protocols, but also support NMEA as well.

The NMEA standard interface is basically a very rudimentary subset of RS-232 that should interconnect with computing equipment. This stnadard facilitates doing things like hooking your GPS up to yoru fish finder (NMEA -- national marine electronics association).

Some cheap OEM devices designed for embedding in equipment don't even do that -- they simply send TTL level bits over the TX interface (0v = 0, 5v = 1, instead of -5 .. -15v = 0, +5 .. +15v = 1). This will work fine with some equipment but not others; for example laptops will generally receive the TTL level data as normal serial data, but PDAs usually don't.

So, my guess is the poster is requiring something whose overall structure looks like this:

GPS --> NMEA fix extraction --> Text Formatting --> Overlay text on live video --> record.

There are degrees of freedom in each step of this chain. For example, a laptop could take the RS-232 from an consumer handheld, use a Perl script to extract the NMEA strings and format them, take a live video feed over Firewire and use the built in facilities of some video capture software to overlay the text on the video and save the video to the laptop's hard drive in MPEG format.

That said, this particular solution probably doesn't meet his needs because he probably wants to be able to walk around with his compact camera.

Build it yourself

[kinema]

If you're interested in a self built solution I recommend you take a look at an article I saw in Circuit Cellar's January '04 issue, Remote Observation Station(PDF. by by Richard Dreher.

Re:BOB

[Telecommando]

McAfee Astrometrics has complete plans for building a time code inserter using the BOB3. It can also be configured to provide lattitude, longitude, altitude and date.

http://mysite.verizon.net/vze8uqf1/id4.html

Subtitles

[nerd65536]

The simplest, easiest and cheapest method is to encode your GPS data in a text subtitle format. For example, srt looks like this: 1 00:00:06,070 --> 00:00:08,070 Hello. The subtitles can be added in post processing, or just accompting the video file.