Re: Open hardware AV to digital conversion

From: smf <smf_at_null.net>
Date: Sat, 10 Jan 2015 12:50:50 +0000
Message-ID: <54B1202A.6070108@null.net>
If you create a 624 line frame, made up of two fields that are 312 lines 
each then it's not a valid PAL signal and no tv will think it's interlaced.

To make it interlaced you have to alternate between vsync happening at 
the end of the last line and in the middle of the last line. To keep the 
speed right you'd be alternating between 311.5 & 312.5 lines, which 
isn't valid PAL either and so may work better or worse than the standard 
c64 signal based on what equipment you are using.

The same problem exists for NTSC but with different numbers. PAL also 
has the problem of alternating phase, which you'll probably need to take 
into account.

On 10/01/2015 12:12, Ingo Korb wrote:
> The PAL VIC-II outputs 312 lines per frame according to the table shown
> at [1], so if you convert those two into fields you end up with 624
> lines per field instead of the 625 that PAL specifies. For NTSC the
> result would be 526 lines instead of 525.


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Received on 2015-01-10 13:01:21

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