"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

tim... wrote:


"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

It's still a high precision optical component, probably with four or five
elements, at least one of which is probably glass. Would it also have
aperture blades?

On 24/10/2019 09:18, tim... wrote:


"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



The rest of the components probably cost fractions of a penny to make :-)


--
Graeme Wall
This account not read.

"Recliner" wrote in message
...
tim... wrote:


"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

It's still a high precision optical component, probably with four or five
elements, at least one of which is probably glass. Would it also have

not the one on mine

a single moulded item

aperture blades?

that is behind the glass not within the glass

"Graeme Wall" wrote in message
...
On 24/10/2019 09:18, tim... wrote:


"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



The rest of the components probably cost fractions of a penny to make :-)

like all ICs

but they tend to cost dollars to buy

Not worked on this product class, not sure if this will be single chip
solution or not?

I have an unused one sitting on my shelf that I can't "give away" [1],
perhaps I'll break it down

tim

[1] to someone deserved of being give it

tim... wrote:


"Recliner" wrote in message
...
tim... wrote:


"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

It's still a high precision optical component, probably with four or five
elements, at least one of which is probably glass. Would it also have

not the one on mine

a single moulded item

I'd be very, very surprised. You'd get horrible image quality, unacceptable
even for a dashcam, with such a basic, single element lens. The elements
may be moulded plastic, but there are almost certainly several of them.


aperture blades?

that is behind the glass not within the glass

In all my many cameras and lenses, the aperture blades are between the lens
glass elements. But a small, cheap lens like this may have a fixed
aperture, with sensitivity controlled electronically. I also assume there's
no image stabilisation in such a cheap model.

In message , at 08:47:39 on Thu, 24 Oct
2019, Graeme Wall remarked:

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.

If I pan it down much, then you get a great view of the bonnet.

The vertical wide angle is a consequence of the horizontal wide angle.
An alternative would be to letter-box crop the video.

I agree I don't think I've quite got the compromise completely right.

This is an alternative (but has the time/date which is distracting for
this kind of posting): https://www.youtube.com/watch?v=SjzEdKFbZ3Q
--
Roland Perry

In message , at 09:41:10 on Thu, 24 Oct
2019, Recliner remarked:

In all my many cameras and lenses, the aperture blades are between the lens
glass elements. But a small, cheap lens like this may have a fixed
aperture, with sensitivity controlled electronically.

It's much better after-dark than I was expecting. Quite an impressive
dynamic range.

I also assume there's no image stabilisation in such a cheap model.

That would require extra processing power.

My PC-based editing software will do image stabilisation
post-processing, but to some extent the "wobble", or perhaps lack of, as
the car goes over the level crossing [at 30.0mph] in that video is part
of the experience I'm trying to capture.
--
Roland Perry

On Tue, Oct 22, 2019 at 07:02:49PM +0100, Roland Perry wrote:
In message , at 16:08:54 on Tue, 22 Oct
2019, Recliner remarked:
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.

I think that shows it's quite some time since you were on the
naughtynet! Looking at dodgy copies of rugby world cup quarter finals
highlights as an example, in the list I'm looking at right now no-one is
offering files that highly-compressed. Of those that are on offer, the
least popular is the most compressed (348MB for 32 minutes) and the most
popular is the least compressed (1.56GB for 32 minutes).

--
David Cantrell | Official London Perl Mongers Bad Influence

Longum iter est per praecepta, breve et efficax per exempla.

Roland Perry wrote:
In message , at 09:41:10 on Thu, 24 Oct
2019, Recliner remarked:

In all my many cameras and lenses, the aperture blades are between the lens
glass elements. But a small, cheap lens like this may have a fixed
aperture, with sensitivity controlled electronically.

It's much better after-dark than I was expecting. Quite an impressive
dynamic range.

I also assume there's no image stabilisation in such a cheap model.

That would require extra processing power.

My PC-based editing software will do image stabilisation
post-processing, but to some extent the "wobble", or perhaps lack of, as
the car goes over the level crossing [at 30.0mph] in that video is part
of the experience I'm trying to capture.

I think small, cheap cameras have no moving parts, so no optical IS, no
mechanical shutter, no aperture blades, no lens cover, fixed focus and no
optical zoom. More expensive dash cams might include some of these 'luxury
features'.