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Uncompressed Digital Video vs. Uncompressed Digital Audio
G
Gene
Interesting little box, bet there are some really mean
little DSP(s) inside... probably not 386 code...
************* cut-n-paste**************
Can the DiskPacks simply be connected to another computer to access the
data?
The Codex DiskPacks feature proprietary hardware connectors designed for
thousands of connect/disconnect cycles and this precludes them from simply
being connected to any other computer to access this original data.
Moreover, the material on the DiskPacks is not stored in an
industry-standard format (such as DPX frames) but in the camera source's
native output - conversions to DPX, QuickTime, HD video, AVI etc. are done
only when the material is accessed in a Codex system.
Gene
little DSP(s) inside... probably not 386 code...
************* cut-n-paste**************
Can the DiskPacks simply be connected to another computer to access the
data?
The Codex DiskPacks feature proprietary hardware connectors designed for
thousands of connect/disconnect cycles and this precludes them from simply
being connected to any other computer to access this original data.
Moreover, the material on the DiskPacks is not stored in an
industry-standard format (such as DPX frames) but in the camera source's
native output - conversions to DPX, QuickTime, HD video, AVI etc. are done
only when the material is accessed in a Codex system.
Gene
A
Arny Krueger
Don Pearce said:
I think I saw something about 20,000 Pounds. I think that was currency, not
weight - right? ;-)
N
Norbert Hahn
Radium said:
Have a look at http://en.wikipedia.org/wiki/CCIR_601
This is closest to raw digital video.
Norbert
R
Richard Crowley
CCIR 601 appears to be 4:2:2 That means that the
chrominance data is compressed 2:1 (Like analog NTSC
is).
Of course DV is compressed 4:1:1 (NTSC) or 4:2:0 (PAL)
R
Ron N.
Only if you regard reducing the sample rate as a
form of compression. But then your typical 44.1kHz
audio CD has also likely been reduced in sample rate
from 48 or 96 kHz as recorded in the studio. Is
that compression? Or just an appropriate choice
of filtering and data format?
The chrominance in 601 is reduced to a bandwidth
that better matches the typical human perceptual
bandwidth of the luminance channel.
IMHO. YMMV.
R
Richard Crowley
If it weren't compression, they wouldn't bother doing it.
Many would say "yes".
Selecting a sample rate always performs some sort of
"compression". One could argue that setting the sample
rate of audio merely selects what you want your HF
cutoff to be.
OTOH, purposely digitally sub-sampling (or analog band-
width-limiting) the color part of the image is a data-saving
perceptual shell game similar to the lossy compression
done by MP3, AAC, Ogg, et.al.
And yet the casual observer can tell the difference
between full-bandwidth RGB and reduced-color rez
video transmission schemes when viewed side-by-
side.
G
glen herrmannsfeldt
Ron N. wrote:
(snip)
There was a story in Popular Science many years ago that I
still remember about storing fast scan (normal TV) video
on 0.25 inch audio tape. It ran the tape at 120in/s,
with the cover page of the story showing the results after
the tape breaks. They heat the record/play head to reduce
friction. 10 inch tape reels were normally used to get a
reasonable time. I don't believe it ever got popular.
-- glen
(snip)
There was a story in Popular Science many years ago that I
still remember about storing fast scan (normal TV) video
on 0.25 inch audio tape. It ran the tape at 120in/s,
with the cover page of the story showing the results after
the tape breaks. They heat the record/play head to reduce
friction. 10 inch tape reels were normally used to get a
reasonable time. I don't believe it ever got popular.
-- glen
V
Vladimir Vassilevsky
glen said:
When I was a kid, I was trying to record the video signal from TV to a
modified conventional cassette tape recorder. For that purpose, the
recorder was operating in the fast forward mode, so the tape speed was
about 2m/s. I was able to establish the horizontal and vertical sync,and
even to see something, however I woudn't call this a picture.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
S
Steve Underwood
I used to use 2" wide (so far more robust) instrumentation tape at 120glen said:
inches/second. The drives used air bearing guides, to reduce friction,
but dragged the tape across ordinary heads with no special method of
dealing with heat or friction. They did have elaborate arrangements to
stabilise the tape as it passed over the heads, though. A 15" reel of
tape ran for about 16 minutes, and had 24 or 28 tracks. Those drives
used to be the mainstay of instrumentation in a number of fields (mostly
military). They could put a fair quality TV picture onto each of their
24 tracks. Several people made drives of that kind - Ampex, Honeywell,
Enertec, and others. We used to fly compact versions, while large floor
standing ones were used in the lab.
So, the popular science article was not describing anything crazy. I
just wonder about handling 0.25" tape at that speed.
Regards,
Steve
M
Mr.T
Richard Crowley said:
Not at all. Compression involves a manipulation of data *within* the range
under consideration. (either lossy compression or lossless)
If extraneous data falls completely outside the required range, then no
compression is necessary within that range.
No, there would be no *real* argument at all, since that *is* what it does.
MrT.
R
Richard Crowley
And limiting the bandwidth is a form of "data compression".
It was invented before our grandparents were born in
the days of early telephony.
J
Jerry Avins
Richard Crowley wrote:
...
Call it data reduction if you wish. "Compression" is generally given a
more restricted meaning.
Jerry
...
Call it data reduction if you wish. "Compression" is generally given a
more restricted meaning.
Jerry
M
Michael A. Terrell
Jerry said:
That is also the definition of "Creative recycling".
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
M
Mr.T
Richard Crowley said:
No, you are simply misusing the term "compression".
By your definition *everything* that does not include DC-infinity (ie.
everything full stop) is therefore "compressed".
Good luck with getting that generally accepted as a new definition.
MrT.
