Monday, June 16, 2014

Garmin GCV Sonar Recording Movie Making

This little demonstration video turned out to be more of a challenge than I had anticipated, but in part it was my fault... sort of. The documentation didn't anticipate I would be dealing with three different Garmin 741xs MFD's, about 6 hours of sonar recordings archived on my computer from two of them, and a chart from a third. But with some excellent and very patient tech support from Garmin it all got sorted out. 

It also required some experimentation to get decent image quality. I started with the original very sharp recordings, played them back in Garmin's Homeport software. The recorded playback was captured using BB Flashback Express screen recording software. The newly created file was exported to a AVI format. From there the AVI clips were edited, and a simple soundtrack was created. The whole thing was then converted into a WMV format for upload to Youtube.

With each conversion you lose a little resolution. Aargh matey, I was in need of Dark and Stormies by the time I was done, but in the end I was happy with the results. It would have been better if the original recording format was a little more video friendly.

For those who want to do this, I'm proffering my experiences so you don't have to contend with the learning curve. The playback of sonar recordings in Homeport is straightforward and simple. You take the chip with the sonar recordings and stick the it in a card reader. You'll also a need a map chip in a second card reader. I haven't experimented whether you can combine these two sets of data together on one card.

If you blow up the image next door you will see in the "Devices" (card readers or other Garmin products) section there are two different Garmin 741xs's listed. The system doesn't differentiate, but in this case the first device (H) is the actual chart I downloaded from one of the units.

The second device (J) has the sonar recordings. Lesson one. I had taken the files, a lot of them, and moved them to my desktop. Mr. Gates didn't like the fact there were folders with the same "Garmin" name so I had to change them. For example the set of  Near Shore reef recordings I named Near Shore. Okay no points for originality but at least I knew what they were.

Homeport's software doesn't like different names. So each time I changed sonar recording folders I had to rename the folder correctly using the Garmin format. In short no deviation from the original folder names. The folder format and contents must be exactly as it was created. There is an exception here. You can rename the Sonar files. You can see one in the list titled "Active Captain." 

When making a video you have four playback speeds. They run from 1x real time to 10x fast time. In my little video the first recording is in real time, but the rest I sped up for everyones sake.

Homeport play back quality (smoothness) is dependent on your computer's processing speed. I don't have a slow computer, but it's not a Cray supercomputer either. I got smoother, but not always perfect motion if I shut down unnecessary applications.

The Rant as usual is always on a budget so the screen capture programs I tried are both free. The first one was CAM Studio 2.7. I had mixed results. What seemed to be going on is if I increased the frame rate to improve the moving image quality the process overhead seemed to make things a bit jerky. The plus of CAM Studio is the output is in a AVI format and produced a slightly sharper image.

Overall I got better results with BB Flashback Express's software. You can take the video file and export it as a AVI. It was easy to use and free, but you have to register the software within thirty days. They do have an upgraded version which I'm considering buying. Try them both and give me a second opinion.

For grins I added a sound track that is a CHIRP from 405kHz to 440 kHz. This is the low CHIRP frequency range of the GCV 10. The only difference is the actual chirp occurs over a few milliseconds, and here each CHIRP is one second in duration. I also turned the output volume way down so it wouldn't be so annoying. The audio software I used is Audacity. It's an open source package that has professional grade capabilities, but is still easy to use. 

Last but but not least each AVI clip was loaded in my Microsoft Live Movie Maker program. I clipped out all of the deadly boring segments, added titles, captions, and credits. Look out Spielberg, I'm gunning for your job.

It was interesting, and at times a little frustrating and tedious to do this. The multiple format conversions did degrade the video a bit, but not as badly as it could have been and I'm generally pleased. I have asked Santa if he would put a utility into my Homeport software stocking that would convert the Garmin RSD sonar files directly into a high rez AVI or equal format. Hopefully this will happen faster than I got my QWERTY keyboard. I have a lot of recording footage left, and more to come.

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