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PAL color loss? Help needed!

PAL Stella Emulation Color loss

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#1 Thomas Jentzsch OFFLINE  

Thomas Jentzsch

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Posted Fri Dec 8, 2017 4:54 AM

Stella has an option which emulates color loss on PAL CRT TVs. This color loss, where only grays instead of colors are displayed, happens in Stella when the scanline count is an odd number and a PAL mode is selected. This has always been assumed to be correct. But there exist a number of ROMs, which produce an odd number of scanlines and are clearly meant to be PAL.

 

This finally made me wonder. And therefore I wrote a simple test program and tested it on my own PAL CRT (14" Sony Trinitron KV-14LT1E), attached to my composite modded console. And no matter what number of scanlines I try, there is no color loss at all! Now I wonder if this is special for my TV/console combination (most likely) or if color loss doesn't work like we assumed for 20 years now.

 

If you own a PAL CRT, please give the attached program a try. Use joystick up and down to change the number of scanlines. Do you get a colored picture for odd scanlines too? When you report back, please provide some details about the TV and the input (antenna, composite, RGB...) you have used too. 

 

Thanks in advance!

Attached Files


Edited by Thomas Jentzsch, Fri Dec 8, 2017 4:56 AM.


#2 Cambouis de l'Atari OFFLINE  

Cambouis de l'Atari

    Moonsweeper

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Posted Fri Dec 8, 2017 7:39 AM

Hello !

 

My light sixer does lose its colors.

It's that one :

2017 12 08 14 27 51
 
Connected to the crt through antenna (an old Philips that only have coax input)
 
Some details about its behaviour :
- each odd scanline count is grayscale
- the display gets more fullscreen at 287 (60hz detection ?)
- it starts to roll at 243

 

 

Don't you think the main difference is your composite connection ? Isn't the color coded another way than through antenna ?

 

Hope this helps ;)


Edited by Cambouis de l'Atari, Fri Dec 8, 2017 7:42 AM.


#3 Thomas Jentzsch OFFLINE  

Thomas Jentzsch

    Thrust, Jammed, SWOOPS!, Boulder Dash, THREE·S, Star Castle

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Posted Fri Dec 8, 2017 7:58 AM

Thanks! I hope with more results we will find a pattern.

 

BTW: Your TV sync limits are exactly mine too.







Also tagged with one or more of these keywords: PAL, Stella, Emulation, Color loss

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