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.

In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.
--
Roland Perry

On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do realtime
video compression. The hardware is probably commodity by now.

In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do realtime
video compression.

They produce files in MP4 format, but not very much compressed. My phone
produces typically 150MB per minute (1920 x 1080 pixels).

The hardware is probably commodity by now.

My whole dashcam only cost about £30.
--
Roland Perry

Roland Perry wrote:
In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do realtime
video compression.

They produce files in MP4 format, but not very much compressed. My phone
produces typically 150MB per minute (1920 x 1080 pixels).

So, Full HD video.


The hardware is probably commodity by now.

My whole dashcam only cost about £30.

That doesn't leave much budget for the lens.

In message , at 20:37:27 on Wed, 23 Oct
2019, Recliner remarked:
Roland Perry wrote:
In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do realtime
video compression.

They produce files in MP4 format, but not very much compressed. My phone
produces typically 150MB per minute (1920 x 1080 pixels).

So, Full HD video.

Like my dashcam (I presume the camera is essentially the same as that in
a phone).

The hardware is probably commodity by now.

My whole dashcam only cost about £30.

That doesn't leave much budget for the lens.

The lens is quite large (1.5cm), and wide angle (170 degrees). And yes,
it's probably one of the more expensive components.

But I run my dashcam at the lower setting of 720p, so that the SD card
fills up slower, which results in video a bit like this *after* it's
been cropped and re-compressed by video editing software to 30MB/min
@720p, and reprocessed by YouTube to 144-720p depending on the view you
select.

https://www.youtube.com/watch?v=F4aHaSyBHvE

(Rail-related content)
--
Roland Perry

On 24/10/2019 07:27, Roland Perry wrote:
In message , at 20:37:27 on Wed, 23 Oct
2019, Recliner remarked:
Roland Perry wrote:
In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users
having to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do
realtime
video compression.

They produce files in MP4 format, but not very much compressed. My phone
produces typically 150MB per minute (1920 x 1080 pixels).

So, Full HD video.

Like my dashcam (I presume the camera is essentially the same as that in
a phone).

The hardware is probably commodity by now.

My whole dashcam only cost about £30.

That doesn't leave much budget for the lens.

The lens is quite large (1.5cm), and wide angle (170 degrees). And yes,
it's probably one of the more expensive components.

But I run my dashcam at the lower setting of 720p, so that the SD card
fills up slower, which results in video a bit like this *after* it's
been cropped and re-compressed by video editing software to 30MB/min
@720p, and reprocessed by YouTube to 144-720p depending on the view you
select.

https://www.youtube.com/watch?v=F4aHaSyBHvE

(Rail-related content)

Nice view of the sky, you need to pan the camera down a bit to see more
of the road.

--
Graeme Wall
This account not read.

"Roland Perry" wrote in message
...
In message , at 20:37:27 on Wed, 23 Oct 2019,
Recliner remarked:
Roland Perry wrote:
In message , at 19:05:11 on Wed, 23 Oct
2019, remarked:
On Wed, 23 Oct 2019 09:34:49 +0100
Roland Perry wrote:
In message , at 07:41:34 on Wed, 23 Oct
2019, remarked:

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.

I think it's because they don't want to have the silicon|dollars|power
budget of compressing the video. They externalise it to users having
to
buy stupidly big SD cards.

My previous dashcam gobbled through 1.2GB for each ten minute file.

There must be more to it than that. Even cheap smartphones can do
realtime
video compression.

They produce files in MP4 format, but not very much compressed. My phone
produces typically 150MB per minute (1920 x 1080 pixels).

So, Full HD video.

Like my dashcam (I presume the camera is essentially the same as that in a
phone).

The hardware is probably commodity by now.

My whole dashcam only cost about £30.

That doesn't leave much budget for the lens.

The lens is quite large (1.5cm), and wide angle (170 degrees). And yes,
it's probably one of the more expensive components.

I don't see why

non focusing, non zoom-able lenses cost pennies to make

tim