Videoprocessing problems

[Altera_Forum]

Hello all, 

 i got some problems with some video and image processing moduls.  the first is the scaler, here the description of the structure:  i got an display with 800x480 RGB parallel with 8 bits (at all moduls) seperate Vsync and Hsyndc and use an test-pattern-generator with color bars and output format of 720x576 for the input signals, the scaler is set to inputformat 720x576 and outputformat of 800x480, the algorithm is nearest neighbour, an clocked video output gives the right hsync ,vsync and the blanking periods. the problem is if i try that the display shows some skewed bars if i use downscaling, upscaling is working.   the second is the deinterlacer: the display is the same and the clocked video output also. the scaler is changed for an deinterlacer the testpattern generator is set from progressive to interlaced output(f0 synchronized). the deinterlacer is set to maximum inputs 800x480 deinterlacing method is bob-scanline-duplication with no buffering, output frame rate: as input frame rate(fo synchronized).  here is the problem that the output picture(bars) is cut from top and only a black horizontal bar, no settings helped till now.  the third is the clipper: the same problem like the deinterlacer...    only the testpatterngenerator with no other moduls is working...   if anybody can help or give some advices, i would be very gratefull.  regards  

[Altera_Forum]

maybe my question was not so good formulated. 

 is it possible to downscale formats from 800x480 to uneven formats like 769x433 or something like that? How is the format calculatet? the even scaling seem to run..  it would be nice if anybody can give me a hint.  greets

[Altera_Forum]

Yes you can scale from almost any input resolution to almost any output resolution. If you are using the nearest neighbor algorithm for the scaler, all you have to do is tell it what output resolution you want. However, the bigger question is how are you going to display this. If you are going to drive a monitor at say 800x480, you need a mixer to place your scaled video (769x433) on top of a 800x480 output. 

 Jake

[Altera_Forum]

thanks for the answer, 

 tried it in all combinations and with a nios 2 processor changing the scaling factors, but still no results on the screen(except the layer 1 is dissabled). so its still the same...  greets

[Altera_Forum]

Ok, the problem is solved. 

 It seems that the scaler input frequency should be higher as the frequency of the video output...

[Altera_Forum]

skewed bars is due to not placing the pixel's at proper address 

so try cheque pixel address