I took a video file (mp4) and cropped it into smaller sections to display on the matrix. Most of them render just fine, but a few of them have the right-two columns of the matrix displaying red and green vertical lines from top to bottom. I've double-checked the video file and zoomed in and I can't see any pixels in there that could be interpreted as vertical lines like that.
They appear faintly in the model preview, but on the actual Matrix they are bright as can be.
At first I thought it could have been the way xLights was shrinking the video to fit on the matrix, but even if I choose Maintain Aspect Ratio they appear (just shorter).
Any thoughts?