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Old May 29th 14, 02:55 AM posted to rec.photo.digital
Alan Browne
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Default Sony's new A7s (12mp FF) why do you need a separate "recorder"to record HD and 4K video?

On 2014.05.28, 18:26 , Alfred Molon wrote:
In article , Alan Browne
says...
Bring it down a notch to 4:2:2 (per the dpreview article).

"The camera can read out its entire sensor fast enough to output 8-bit
4:2:2 4K video over HDMI at up to 30p, without the need for line
skipping or pixel binning."

Still - a lot of bandwidth - about 800 MB/s.


Doesn't the camera use at least a bit of compression to bring down the
data volume?


I don't know. The above is a rough (from the linked calculator) about
how much information is produced. Compression could probably cut that
by about 20%, perhaps more.

Another issue is how fast a disk drive can take a sustained write. RAID
arrays are used to split the bandwidth (striping). Compression would
help reduce that load as well.

Redundancy would drive the disk number up (double or triple). RAID
striping increases complexity (and processing at the storage end too, I
guess).


--
I was born a 1%er - I'm just more equal than the rest.