On Tue, 22 Oct 2019 21:21:38 -0000 (UTC)
Billy No Mates Always On His Own Billy No Mates Always On His Own.usenet@gmail.
com wrote:
Roland Perry wrote:
In message , at 16:08:54 on Tue, 22 Oct
2019, Billy No Mates Always On His Own Billy No Mates Always On His Own.usen
remarked:

[CCTV]

Presumably they'll have moved on from HDDs to solid state storage by now?
They're only storing relatively low res compressed JPEGs, so the files will
be small.

My dashcam stores ridiculously uncompressed video.

250MB every 5 minutes.

Downloaded TV shows are typically 200MB for their 42 minutes.

Which is trivial. My A7Riii‡ camera's RAW images are 41.3 MB, and it can
shoot 10Â*of those per second (ie, more than 200MB in 0.5 sec). The memory
card in the first slot holds 5840 images, and potentially the same again in
the second slot.

Those low res bus camera compressed JPEGs are probably well under 0.5MB
each. If it stores one image per sec from, say, eight cameras, that's maybe
200MB/min at most, probably much less.

‡ Here's some pics I took last week in Ely with that camera:
https://www.flickr.com/photos/Billy No Mates Always On His Own/albums/7215771
1379885958

I wonder if dashcams storing low/uncompressed video is so it can accurately
capture very fast movement - eg just before an accident - which most video
compression systems are not particularly good at.