exiftool to manage DJI media files

DJI Drones don’t seem to remember the image count between formats of a media card. This creates a problem for me when I’m trying to backup and maintain my images and video.

Because the dates are all correct in the media files, retrieved from GPS data, organizing the files by naming them based on the date works for me.

Using ExifTool by Phil Harvey is a great solution for pulling the metadata from the files and renaming the files.

The command line that I was initially using is:

exiftool "-FileName<${CreateDate}.$filetype" -d %Y%m%d-%H%M%S%%-c -ext mp4 -ext dng -ext jpg dji*

It’s problem is that it orphans the SRT subtitle files from my videos that I’d like to keep matching the video files.

I’ve tried this variation to do it in one step but it doesn’t work, because the SRT files get renamed as MP4 files.

exiftool -verbose "-FileName<${CreateDate}" -d %Y%m%d-%H%M%S%%-c.%%le -ext mp4 -ext dng -ext jpg dji* -srcfile %f.srt

If anyone has a suggestion for how to rename all the media files in one directory I’d appreciate it. Even running two commands in sequence would be fine.

Update:

I’ve figured out that running these two commands in sequence will get me the results I am looking for:

exiftool "-FileName<${CreateDate}" -d %Y%m%d-%H%M%S%%-c.srt -ext mp4 -srcfile %f.srt dji*
exiftool "-FileName<${CreateDate}" -d %Y%m%d-%H%M%S%%-c.%%le -ext mp4 -ext dng -ext jpg dji*

I’m still looking for a way of doing it in a single command that may leave less room for error, but this is working for now.

Being a responsible drone pilot

I try to be a responsible drone pilot. I use the FAA B4UFly App on a regular basis to see what it has to say about locations that I’m interested in flying. Unfortunately, it lists every uncontrolled heliport as an airport and reports “Action Required” so often as to be nearly useless.

Yesterday I was sitting on the beach at Golden Gardens Park in Seattle, watching sailboats race offshore. I thought it would be good to check to see what the app would show. I was sitting at sea level, with a hill near me that would be at least 200 feet high. The rules for drones say that you are not allowed to fly over 400 feet above the surface without permission from the controlling authority. Aircraft are not allowed to fly below 700 feet without similar permission.

GoldenGardensVFR

Golden Gardens is located about where the “E” in KENMORE sits on the map above. It’s under the Class B Airspace that starts at 3,000 feet, going up to 10,000 feet.

While understanding VFR charts  may be more than the average drone pilot should be expected to recognize, especially for a dense area like Seattle, the B4UFly App’s tendency to show warnings is similar to the boy who cried wolf. It’s impossible to recognize when an action is really appropriate.

AMA Membership and BestBuy

An interesting thing I found in the drone aisle in BestBuy was a card to join the Academy of Model Aeronautics.


I’ve been a member since I got involved with drones. I had to become a member to join the rc flying club I frequent. It’s good to see that it’s being easy to recognize in consumer stores, as opposed to the complete hobby level word of mouth that I’ve seen in the past.

Best Buy and DJI Accessories

I don’t shop too much locally for technology, because it always seems that what I want is not available locally. Yesterday I was wandering around killing time and went into the local Best Buy.  Instead of just looking at the normal things I might go for in a best buy, I looked around to see what was new. They now have an aisle dedicated to drones. There were complete drones from DJI, Yuneec, and several other manufacturers. More interesting to me was that they carried accessories for those drones as well.  I knew that they sold drones on-line, it just never occurred to me to look at them in person in the store.

I bought a Mavic Pro directly from DJI soon after they were released. I got the Fly-More package that entails several items including spare propellers. I’ve not needed to replace a propeller in my first 7 hours of flight time but it’s nice to know that propellers are available locally. DJI charges slightly less, $9.00, but they charge for shipping, and you have to wait for the item to arrive.

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DJI Phantom and Wind

This week I took my drone to video Initial Point in Idaho. It’s a rocky outcrop about 20 miles south of Boise that was chosen as the initial survey point for the Idaho Territory in 1867. It has a concrete platform installed at the top with a survey marker embedded. There’s a rocky trail that can be driven to the top if your vehicle has a high ground clearance. I chose to walk to the top.

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Initial Point Idaho

My car was parked at the base, I climbed up about 130 feet to the top. The wind was occasionally gusting at the base. It was constant at the top, with much higher gusts.

I carried the drone in my backpack to the top, and launched it from the platform. I manually flew it around the point, but was feeling extremely nervous doing so. I only flew about 36 feet above the platform during the entire flight.

The concrete platform has a metal railing surrounding it, and I didn’t trust the drone to return safely to land without hitting the railing so I manually had it land nearby. As I was hovering the drone before landing, it was holding a fairly constant 20° lean because of the wind.

After hiking back to my car I still had plenty of battery for another flight. From near my car I launched the drone and flew vertically to about 200 feet, centered the drone over the survey marker, and used the point of interest feature to create a video circling the point.

I don’t believe that the wind was any less on my second flight than it was on my first flight. The fact that I was in the wind on the first flight had me feeling significantly more nervous while flying than when I was out of the wind on the second flight. Watching the video from the first and second flight doesn’t appear significantly different. I would have liked the point of interest video slightly more if I’d been on top of the point the entire time, but I was too nervous to do it all while I was sitting in the wind myself.

DJI Battery Monitoring

DJI charges a significant amount of money for their batteries and calls them Smart Batteries. I’ve seen the statistics reported of how many times the battery has been power cycled, as well as details of how much flight time is available. This was a new and interesting feature to me.

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I had left the drone in the back of my car overnight. The temperature had probably gotten into the high 30s, and was still in the mid 50s with the sun shining. The warning message “Battery Temperature Too Low. Warm battery to at least 15 degrees Celcius before flying” came up on my screen and would not let me initiate a takeoff.

I have used batteries in cold climates in the past. I know how temperature affects both current output from batteries and future usability. I’m impressed that DJI has built in this feature to their firmware.

DJI Phantom 3 Standard

DJI has been the standard drone that people visualize when they think of consumer drones for the past several years. It’s a white quadcopter that comes with a white remote control.

This drone is the camera platform I was hoping for when I got into drones three years ago. The flights are very automated, the camera controls are fully integrated, and I can start flying in a new location with very little setup time. The picture below was taken to demonstrate how close the drone came to returning to its launch location and automatically landing after flying over a thousand feet away from where I was standing. The drone had taken off from on top of the ring, and it landed less than 4 feet from the same location.

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In early March DJI dropped the prices of their entire line, convincing me to buy the least expensive unit, now on sale for under $500. I ordered it on March 18th, received it on March 23rd, but didn’t successfully fly it until March 29th.

I live in downtown Seattle. I didn’t want my first flight to be anywhere that would draw excess attention. I’ve been flying drones for three years now, and have grown accustomed to things going wrong. I’d planned on flying at the RC field I regularly visit on the evening of  March 24th. When I got there, first I was not able to get the drone to power on, then when I figured out how to do that, I was forced to do a firmware update before I could fly. By the time I’d got all that out of the way I was running late for a meeting. I decided that the safe thing was to put everything away until my next opportunity.

The Phantom 3 Standard is delivered with two sets of propellers, the transmitter / remote control, a flight battery, an AC battery charger, and a few small extra parts related to the camera gymbal.  It is designed to work with an iPhone or Android phone to both control the unit and see what the camera is doing. I don’t have either of those phones, instead I’m using a Google Nexus 7 tablet. The device connects to the transmitter via WiFi. While my tablet is connected to the transmitter it is not able to connect to the internet.

My first flight with the drone was in a Seattle Park. The battery reports that it can fly up to 25 minutes. None of my previous drones would fly for more than about 13 minutes. The controller app on my tablet has plenty of feedback about the battery condition.

Normal flight mode for me has been that I tell the drone to take off via the app. It takes off and hovers about 4 feet in the air. Then I use the sticks to fly the drone to a location telling it to go up/down or rotate left/right with the left stick, and moving horizontally with the right stick. I usually enable the camera in movie mode before taking off, and only take it out of movie mode if I want to take still photos. When I’m ready to finish, I can either drive it back near myself, or toggle the left switch on the transmitter to cause it to go into return home mode. I’ve got it configured so that it will be at least 100 feet above the ground during return to home mode, which is good enough to clear most trees, but I make sure that’s true early in my flight just in case. If the drone loses contact with the transmitter for more than three seconds it will enter return to home mode.

After owning the drone for one month, I also purchased the DJI backpack specifically designed to carry the drone. It has been what really makes the drone fun for me because I can store the drone in the backpack, knowing it’s fully protected, and easily grab the entire thing and throw it in my car to go somewhere that might have interesting things to photograph.