I noticed that using some effects or transitions results in massive image quality loss even if no resizing is occurring. The resulting image almost looks like it was decimated to half resolution and resized back up. For example, the loss of quality is very obvious when using Affine Composite instead of Composite even when affine composite is set to have the identity transform. You can also see it when adding the Pan and Zoom effect without any panning or zooming.
I've attached frame grabs taken using VLC of a lossless H.264 rendering of a clip that consists of one png file. You can see that with pan and zoom the image quality is much worse.
I am working with some screen capture video (from CamStudio) and some DV. I am trying to cut out parts of the screen video and overlay it on top of the DV. The screen capture resolution is 640x480 and the project target is VGA NTSC so no scaling is needed if I want 1 to 1 pixel mapping.
I was able to get 1 to 1 cropping by using the Scale0tilt effect. There is no apparent quality loss with Scale0tilt as long as the crop boundaries are multiples of 4. I was not able to use crop because it always scales so that the pixel aspect ratio is preserved but the cropped out portion is as big as it can be given the output size.
Any ideas on how to work around the image quality loss? I have not found a workaround to using Affine Composite or Pan and Zoom to move the cropped out video around within the image frame.