Budget image.

Thursday, February 27th, 2020

It’s a cold and clear day here in Atlanta, which is very different from this YouTube frame (life this afternoon) of an eastbound train in Fostoria, Ohio.

It’s flurrying up a storm—and it takes a lot of bandwidth to push this picture out.

This is actually a nice high-resolution camera, but like many digital sources in the tubes of the internet, it’s on a bit-budget. If the picture is relatively static‚ if relatively few pixels change from one thirtieth of a second to the next, then the camera system only needs to transmit the changed pixels, and can devote more of its bandwidth to transmitting more fine details of the part of the picture that isn’t changing moment to moment.

Throw a flurry of snowflakes—or a ton of confetti at a political convention—into the picture, and it dumps down to a much lower resolution, because more is changing from frame to frame, and the system has to do its best to depict that.

It’s amazing how low-def high-definition tv can get when the finite number of bits that can fit in the pipe are consumed by tiny flickery fast-moving things.

Same camera, less snow = less of a change from frame to frame.