Re: Interlaced video

[Thomas Harte]

There's a timing difference between even frames and odd fields in the  
syncs generated at the field end. Non-interlaced video essentially  
sends only even fields.

That said, I'm not sure if non-interlaced video was ever an official  
part of the PAL spec, so perhaps this TV is justified in its  
implementation. Though it seems odd, as even technology as recent as  
the Playstation 2 uses non-interlaced video modes for some games.

On 24 May 2008, at 11:20, Tobermory wrote:

I guess it's going to be pretty random.
Hmm interesting.  If its interlace mode for normal broadcast telly  
works,
(ie you always get ABABAB not BABABA) then it must be receiving some  
other
signal to identify the A frames from the Bs.  Does turning off the  
screen
with an OUT 252,0 reset it?

Howard

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:owner-sam- 
[EMAIL PROTECTED] On
Behalf Of Dave Laundon
Sent: 22 May 2008 20:56
To: sam-users@nvg.ntnu.no
Subject: Re: Interlaced video

2008/5/22 Colin Piggot <[EMAIL PROTECTED]>:
Now the question is, depending how the TV is interlacing the  
frames, and
how
many frames there's been since the SAM was powered up - when the
'Interlaced
Pictures' from FRED are loaded the frames might show with the  
intended
'interlacing', or be reversed - if 'A' is the frame with the top  
row, 'B'
is
the frame with the row to be shown below, your telly could interlace
correctly so the TV displays with the lines ordered ABABAB, or  
could be
out
of order and display BABABA....  (hope that makes sense!)

Hmm, I hadn't thought of that.  I guess it's going to be pretty
random.  I'll type that ROLL test in again and keep running it and see
if the orientation changes.  Kind of makes any applications difficult
without a calibration option!

I seem to remember there was a cover tape on one of the magazines that
had a "new display mode" that swapped between two screens at 50Hz or
something.  Can't remember if it was "interlacing" or some method of
increasing colours.  My memory is vague...

Makes me want to dig out those Fred issues with "interlaced"  
images on
them
to see how they look.  If only my drive worked...  (Colin, do you  
still
have
spare belts? :-)

Should do, I'll drop you an email in a bit once i've checked :)

Thanks.  Must get him up and running again :-)

Dave.

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