Calculate video size

HD Output HDMI (1920*1080)

I would like to find out how big a file size for one hour of recording.

It is a CCTV camera with 960h resolution.

I am thinking of buying a 500 Gb drive to store the video.

Thanks.

Andy wrote:
HD Output HDMI (1920*1080)

I would like to find out how big a file size for one hour of recording.

It is a CCTV camera with 960h resolution.

I am thinking of buying a 500 Gb drive to store the video.

Thanks.

Easy-peasy.

The CCTV has a frame rate. Multiply WxH times 3 bytes
(for 24 bit color) times frame rate.

1920x1080x3 * 60FPS = 373MB/sec.

Then, divide by 100 for your typical high-compression
container for the video. Now we're down to 3MB/sec.

If you modify the GOP, for a "long GOP", you can
achieve greater savings on compression/recording.

So if we took my poorly crafted approximation,
we get 10GB/hour. It's probably really only one eighth of
that, or about 1.2GB/hour.

*******

Now, we'll check the web :-)

"cctv hdtv gigabytes per hour"

An estimate for broadcast TV, is 3 to 17mbps for 1920x1080.
But it doesn't say whether that's 30FPS (60i) or 60FPS.
If we round up, call it 4mbps, which is 0.5MBps, we get
1.8GB/hour. The idea being, that if the CCTV is shooting
a hallway, most of the collected content is static. And
then the storage space is a small function of the GOP setting
(12 frames to 600 frames). If you're using hard drive
storage, the peak bandwidth doesn't matter (it's not nearly
the same issue as streaming over the Internet). If you're
recording a hallway and the building catches fire,
recording a live fire *will* use up disk, and at a much
higher rate. If there is a lot of action in a scene, the
compressor needs more bandwidth, and when streaming, the
pipe may not have the capacity for that. Whereas the
disk drives, with a few disk drives in RAID0, you can
practically capture a stream uncompressed.

But if all you're after, is a couple static frames
for police usage, you can try to conserve disk space
a bit. This is only possible, if the product has
some user adjustable settings. Or, the CCTV data is
available uncompressed, and you apply your own compression
method.

If a CCTV camera points out at the street, there can be
a lot of (irrelevant) action in a street scene, which
will require more storage space.

So, optimistically, 500GB divided by 2GB/hour, gives
250 hours or 10 days say. Just enough for a one week
vacation.

Really, these products you're looking for, should list
this in the specs.

Some of the bandwidth needed, is caused by the "noise"
in the sensor. While high frequency noise content can normally
be tossed by a compression algorithm, it sometimes
figures into the "wasted" storage space. You want a CCTV
scene which is "well lit", for least sensor noise. If you
shoot low-light images, expect the bandwidth to increase
on compression of the noise. You might want a camera
with a Sony HAD sensor, for slightly better low light
performance. A webcam just won't cut it.

And there's no such thing as a free lunch. You don't get
video this sharp, at compression ratios of 200:1. There's
got to be some tricks here. Maybe the compressor is adaptive.
Notice there is no sign of sensor noise in that picture.
It does look on the edges of objects, like MJPEG ringing
a bit. But for a frame extracted from a high compression
capture, that looks amazing. It looks like a "live" feed
with no compressor at all. Which isn't reasonable for
CCTV.

http://videos.cctvcamerapros.com/ima...-Recording.jpg

Paul

On Saturday, April 29, 2017 at 8:32:21 PM UTC-5, Paul wrote:
Andy wrote:
HD Output HDMI (1920*1080)

I would like to find out how big a file size for one hour of recording.

It is a CCTV camera with 960h resolution.

I am thinking of buying a 500 Gb drive to store the video.

Thanks.

Easy-peasy.

The CCTV has a frame rate. Multiply WxH times 3 bytes
(for 24 bit color) times frame rate.

1920x1080x3 * 60FPS = 373MB/sec.

Then, divide by 100 for your typical high-compression
container for the video. Now we're down to 3MB/sec.

If you modify the GOP, for a "long GOP", you can
achieve greater savings on compression/recording.

So if we took my poorly crafted approximation,
we get 10GB/hour. It's probably really only one eighth of
that, or about 1.2GB/hour.

*******

Now, we'll check the web :-)

"cctv hdtv gigabytes per hour"

An estimate for broadcast TV, is 3 to 17mbps for 1920x1080.
But it doesn't say whether that's 30FPS (60i) or 60FPS.
If we round up, call it 4mbps, which is 0.5MBps, we get
1.8GB/hour. The idea being, that if the CCTV is shooting
a hallway, most of the collected content is static. And
then the storage space is a small function of the GOP setting
(12 frames to 600 frames). If you're using hard drive
storage, the peak bandwidth doesn't matter (it's not nearly
the same issue as streaming over the Internet). If you're
recording a hallway and the building catches fire,
recording a live fire *will* use up disk, and at a much
higher rate. If there is a lot of action in a scene, the
compressor needs more bandwidth, and when streaming, the
pipe may not have the capacity for that. Whereas the
disk drives, with a few disk drives in RAID0, you can
practically capture a stream uncompressed.

But if all you're after, is a couple static frames
for police usage, you can try to conserve disk space
a bit. This is only possible, if the product has
some user adjustable settings. Or, the CCTV data is
available uncompressed, and you apply your own compression
method.

If a CCTV camera points out at the street, there can be
a lot of (irrelevant) action in a street scene, which
will require more storage space.

So, optimistically, 500GB divided by 2GB/hour, gives
250 hours or 10 days say. Just enough for a one week
vacation.

Really, these products you're looking for, should list
this in the specs.

Some of the bandwidth needed, is caused by the "noise"
in the sensor. While high frequency noise content can normally
be tossed by a compression algorithm, it sometimes
figures into the "wasted" storage space. You want a CCTV
scene which is "well lit", for least sensor noise. If you
shoot low-light images, expect the bandwidth to increase
on compression of the noise. You might want a camera
with a Sony HAD sensor, for slightly better low light
performance. A webcam just won't cut it.

And there's no such thing as a free lunch. You don't get
video this sharp, at compression ratios of 200:1. There's
got to be some tricks here. Maybe the compressor is adaptive.
Notice there is no sign of sensor noise in that picture.
It does look on the edges of objects, like MJPEG ringing
a bit. But for a frame extracted from a high compression
capture, that looks amazing. It looks like a "live" feed
with no compressor at all. Which isn't reasonable for
CCTV.

http://videos.cctvcamerapros.com/ima...-Recording.jpg

Paul

Thanks for the detailed explanation.

Andy

Il giorno Sun 30 Apr 2017 09:16:57p, *Andy* ha inviato su
microsoft.public.windowsxp.general il messaggio news:c55074f8-082e-4d0d-
. Vediamo cosa ha scritto:


Thanks for the detailed explanation.



and thanks for a better (reduced) quoting next time:
https://en.wikipedia.org/wiki/Usenet_quoting



--
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http://www.bb2002.it
............ [ al lavoro ] ...........

On Tuesday, May 2, 2017 at 4:31:32 AM UTC-5, Ammammata wrote:
Il giorno Sun 30 Apr 2017 09:16:57p, *Andy* ha inviato su
microsoft.public.windowsxp.general il messaggio news:c55074f8-082e-4d0d-
. Vediamo cosa ha scritto:


Thanks for the detailed explanation.



and thanks for a better (reduced) quoting next time:
https://en.wikipedia.org/wiki/Usenet_quoting



--
/-\ /\/\ /\/\ /-\ /\/\ /\/\ /-\ T /-\
-=- -=- -=- -=- -=- -=- -=- -=- - -=-
http://www.bb2002.it
........... [ al lavoro ] ...........

You might want to consider spending more time helping folks instead of criticizing them.

Il giorno Wed 03 May 2017 08:58:20a, *Andy* ha inviato su
microsoft.public.windowsxp.general il messaggio
. Vediamo cosa
ha scritto:


You might want to consider spending more time helping folks instead of
criticizing them.



I'm not criticizing, I'm educating

--
/-\ /\/\ /\/\ /-\ /\/\ /\/\ /-\ T /-\
-=- -=- -=- -=- -=- -=- -=- -=- - -=-
http://www.bb2002.it
............ [ al lavoro ] ...........