Thread: Slow Scan TV
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Old November 2nd 05, 12:34 PM
Jan Panteltje
 
Posts: n/a
Default Slow Scan TV

On a sunny day (Tue, 01 Nov 2005 20:02:04 -0500) it happened jim
wrote in :

I AmnotGeorgeBush wrote:
From: (masterblaster777)

Anyone out there using slow scan tv on cb?



Yep.

there was a poster on this board that has done that. iirc they were
using 27.500.

I have typed it in google and found a lot of dead links...
It seems to me (been thinking about this) that best way is go digital,
one could use normal packet at 1200 Bd, a simple .jpg picture in color
of size 352x288 (what many cheap webcams do) gives a VERY good quality
did some tests (Linux webcam software is on my site for Creative Webcam II)
http://panteltje.com/panteltje/mcam/
and now also for the D-Link ethernet webcam:
http://panteltje.com/panteltje/mcamip/
just found an old test:
12520 Jul 4 18:27 mcam.jpg
12520 bytes for a good quality jpg...
So if you could use ALL bandwidth on packet, then that file would go in
12520(bytes) x 8 (bits per byte) / 1200 (bits per second) = 83 seconds.
In reality packet will take longer, especially if noise or interference is
present, then it would re-request transmission endlessly (almost).

One can wonder if in case of multimedia this error correction in the transfer
is needed.
For sure locally a few screwed up bits would still give a picture.
On the other hand digital is extremely sensitive to bit errors.
Different modulation schemes such as used for satellite transmission, and
transport stream format (all small 188 byte packets) would perhaps be an
improvement.

For now the current packet digital network allows transmission of jpg from
webcams.....

Just some thoughts.
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