This is why I sometimes have trouble understanding the advice of experts.
This file was, indeed, what was on the SD card. It is a video I made with a small handheld camera. A one minute video made with that camera would, I assume, be closer to four MB on the SD card. So that's what you would start with, before applying any compression.
I consider it a failure in my explanation when someone can't follow what I wrote, so lets see if I can make it any clearer.
Uncompressed digital video has a data rate of about 200 MB per second. Professional grade HD video cameras send the video out at this rate. Consumer grade cameras compress the video to get the data rate down to something manageable. There are two ways this is done. The first uses algorithms that search for patterns, send the pattern once and then indicate repeats in each pattern throughout the image, and from image to image in the stream of images that make up a video. The second much simpler way to compress the video is to make the image size smaller (less pixels).
My pocket camera offers two different algorithms for compressing the video. The more aggressive one is Motion JPEG, and combined with reducing the image size to 320 by 240 pixels, results in a file of about 35 MB for a one minute video. That is what my camera puts on its SD card.
There are even more aggressive video compression schemes that trade off lower quality video for reduced data rates (and therefore file sizes). If you were using a camera similar to mine, you would need to use a program on your computer that did this further video compression. Evidently the example you gave had a much more aggressive video compression algorithm built into the camera.
Uncompressed HD video takes roughly 12,000 MB for 1 minute of video.
Motion JPEG at 320x240 takes roughly 35 MB for 1 minute of video. That is already an amazing amount of video compression.
Yes there are algorithms that can crunch the rate down lower, but with even further trade-offs in video quality and/or image size. My video editor son just did some tests for me and found that he could get a minute of 320x240 video down to about 3.5 MB, so the file size you mention is certainly possible.