Archive for November, 2018
Nov
1
As many of you know, I’m an active competitor in the sport of performance rally.
I recently returned from the 2018 edition of La Carrera Panamericana, a 3000 km race from Oaxaca, near the bottom of Mexico, to Durango, near the top. It was an amazing challenge and an equally amazing adventure, highly recommended to those who can afford the time and cost to compete.
My usual in-car video camera is a Sony AS-200, but for this race the team used a GoPro Hero 6 Black device. I’ll make some observations about that camera later, but the purpose of this note is to describe the filenames used by the camera as best I can deduce.
The main video files are in the MP4 format and have filenames beginning with “GH” followed by six digits. The first three digits provide grouping information, while the last three are sequential in nature. Since our camera was new, the last digits were quite low, from 070 to 207. The first three digits were generally 010, but with some caveats. For long recordings (approximately 4 GB in size), the camera would switch to a second (or third, or fourth) file. The last three digits remained the same, but the middle digit was incremented.
This is best illustrated by example.
File name
GH010128.MP4 was the first video file for the Mil Cumbres
stage but since it was a long stage
GH020128.MP4 was the continuation of the video.
This means that if you’re using third party video editing software, you would combine these two files, not the “obvious” next file which you would imagine to be GH010129.MP4.
Additionally, each video file has a .THM file and a .LRV file, the latter with a “GL” prefix instead of “GH.” I can’t be sure, but I believe the THM file is an encoded version of a CSS style sheet, while the LRV file contains encoded GPS information. (In contrast, Sony’s cameras use plain text formatting for these type of files.)
I tried using GoPro’s proprietary software GoPro Quik but it had a poor user interface and didn’t always recognize the files that I’d transferred to the computer from the memory card. Perhaps if I had the camera and connected it to my computer (instead of reading just the cards), it would have worked better, but I kind of doubt it. The bottom line is I switched to a package that, while still primitive compared to my old tools, was far more robust.
Now about those other observations regarding the camera itself. It has a very compact form factor, making it easy to mount it in a variety of places. The picture quality is very good. (We were shooting in 1080 but 4K is available.) On the down side, battery life is poor, the user interface is difficult unless you can see the back of the camera (and it has a touch screen), it often inverted the images for no reason I could determine, and you can’t hook up a remote microphone without buying a special adapter for a non-standard connector. If you accidentally push the power button, the mode changes unless you hold it down for a while. The GPS components are a great idea, but the manual says you should mount the camera right-side-up for GPS to work best, something that’s not always possible.
In my opinion, the GoPro cameras are well suited for activities like skiing, cycling, and skateboarding. I’m less impressed with it in motorsports applications, though many of my colleagues swear by them instead of at them.
The bottom line is that if you understand the file naming convention, you can work with the output of these cameras more effectively, regardless of the editing software you use.