Re: Currently-Available Highest-Quality Linear PCM Video?

Radium wrote:
Bob Myers wrote:
"Radium" <glucegen1@xxxxxxxxxx> wrote in message
news:1161127670.929976.69540@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi:

What are the sample rates and picture resolution [in pixels X
pixels]
of the professional progressive [non-interlaced] linear-PCM
video
format used today? I beleive linear-PCM video signals are used
in
professional studios.

If you're talking about standard-definition television, and
the case of standard sampling formats for the conversion
and storage of "analog" video into digital form, the most
common international standard today is probably CCIR-601,
which uses a common 13.5 MHz sampling rate for both
525/60 and 625/50 video systems; this results in image
formats (not "resolutions," please) of 720 pixels x 480 lines
for the former and 720 x 576 for the latter.

What equation did you use to get the numbers 720, 480, and 576?

I don't know
what you mean by bringing "linear-PCM" into a question of
sampling rates and image formats.

Bob M.

Linear PCM is uncompressed PCM. Thats what I am talking about.
Sampling
rate must be at least twice the highest frequency in the signal. Due
to
physical conditions, it is safe to makes the sample rate at least
2.5x
the highest frequency signal.

In NTSC, the horizontal frequency is 15.734 kHz, the vertical
frequency
is 60 Hz, and the color subcarrier frequency is 3.579545 MHz. The
means
that the horizontal sample rate must be 39.335 khz or higher, the
vertical sample rate must be at least 150 hz, and the color
subcarrier
sample rate must be no less than 8.9488625 mhz.

What is the pixel X pixel resolution -- or "format" if you wish --
of
today's first-class video signal? Surely it would have to be more
than
720 X 576. My monitor is displaying a pixel X pixel -- or "screen
area"
-- of 1280 X 1024 with 32-bit color. I am not sure of the
frequencies
of my monitor.

Also, is there supposed to be a special difference between the first
number and the second number [such as 1280 X 1024 or 720 X 576]?


Thanks,

Radium

You really need to go look things up and not argue about things you
apparently know little to nothing about. Bob Myers told you exactly
right about SD TV. You can go look this up- the sample rate is 858 x h
rate = 13.5MHz for luma. The 720 is the active number of samples out of
the 858. That 'dead' time is to allow the CRT based monitors time to
retrace the Horizontal. The 480 line is computer talk for 525 line
system of which 483 are active. The remaining lines are to allow
Vertical retrace of a CRT monitor. If you think about it, LCD and
Plasma do not require retrace since there is no scanning, just counting
off samples. HDTV works in a similar fashion but the numbers are all
different. Try ATSC.ORG. The monitor pixel ratios are often 4:3 or 16:9
to make square pixels but none of that is etched in stone. Rectangular
pixels are often used and just re-map the square into rectangular. Now
go study.

GG

.

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