2 Dec
2006
2 Dec
'06
10:45 a.m.
On Fri, 01 Dec 2006 05:14:15 +0100, Jules Richardson <julesrichardsonuk at
yahoo.co.uk> wrote:
Jim Beacon wrote:
Both ATI and nVidia have really good video support these days, and Matrox have of course
been in professional equipment for many years.
have a look at the MYTHTV LINUX package - the
addition of a suitable capture
card and video out card should do the job. We've got it to do various
esoteric television standards, for a bit of a taster of what it can do, have
a look here:
http://www.g1jbg.co.uk/fothtv.htm
wow - that looks like it'll do the job nicely. I suppose the hardware needed
is at the point where it's almost free these days (and certainly cheaper than
a proprietary converter).
I wonder what the quality's like? Going PAL -> recoder -> NTSC obviously
won't
be as good as native NTSC device output. Or, to put it another way, is the
average PCI TV tuner card as good quality as the tuner found in a good TV set?
The tuners I have seen in TV cards are identical to the ones in TV sets. I suppose the
processing after the tunes is what makes the difference, and only a few years ago most PCs
were not really up to real-time video processing without glitches. I have a cheap TV- at
nywhere which works fine until they switch to DTB/MPEG4 and turn off PAL transmissions
next year.
Now that PAL and NTSC have been obsoleted by digital TV, most PCs have the processing
power needed to process PAL signals...
...
(Hmm, you've got me thinking that the museum probably needs the reverse of
what I'm trying to do - something that'll take all sorts of formats as input
and output VGA or PAL...)
VGA is acceptable for IEA-standard NTSC-M material (which has only 482 active lines and
4.2MHz video bandwidth), and I guess it is acceptable for PAL in many cases even though
you want rather higher resolution in order to show all the 574 active lines in a
OIRT-standard PAL-D signal with 6MHz video bandwidth. In both cases I think I would opt
for a 600x800 display running at 75Hz refresh instead of 60Hz 640x480 VGA. You would get
some borders around the picture, but everything would be displayed without any
interpolation artifacts.
Depending on the goals you want to accomplish, there is also a NTSC version for standard B
(625 lines 25 frames/s) and a PAL version for standard M (525 lines 30 frames/s). These
standards were used for transatlantic exchange, and in countries like Brazil which had
US-style B&W transmissions but opted for PAL for colour.
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