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English => Interfaces, Pinouts, Cables => Topic started by: Washwillah on Aug 27, 2006, 16:03

Title: 180° twisted picture on VGA
Post by: Washwillah on Aug 27, 2006, 16:03
Hello!
I have a dvd player with a VGA output. i want to twist a picture with 180° but the dvd player is unable to this. could i do this with the vga connector?  :?:  
thx
Title: 180° twisted picture on VGA
Post by: mimposs on Aug 28, 2006, 18:09
Shortly: no.

If you want to have a picture

+====+
+A==B+
+====+
+C==D+
+====+

turned into

+====+
+D==C+
+====+
+A==B+
+====+

you'd need to store each frame line somewhere untill the picture has fully sent, then start reading each scan line in the inverse order (from the bottom up), sending to the monitor each one in the inverse direction (from right to left).

It looks to me, this in not something you can do just playing with cables. It takes some (fast) electronic, a real framebuffer, plus some simple logic, plus the ability to have this electronic synch with the various VGA frequencies.
Title: 180° twisted picture on VGA
Post by: mimposs on Aug 28, 2006, 18:11
Sorry :P , the idea was:

If you want to have a picture

+====+
+A==B+
+====+
+C==D+
+====+

turned into

+====+
+D==C+
+====+
+B==A+
+====+
Title: 180° twisted picture on VGA
Post by: Washwillah on Aug 28, 2006, 22:52
wow, thanx. it is too difficult for me :)
i have another question: can i transform an s-video or composite output to vga?
Title: 180° twisted picture on VGA
Post by: Kenny on Sep 20, 2006, 04:30
With my uC's and programming, yes, else, no.
It need to be decoded into component/rgb, and then use a pute composite output as sync... it is quite difficult...