I'm using blender as Video Editing software with some images strips as input (rendered PNGs from other blender files).

The problem is that setting Proxy render to anything different than 100%, gives inconsistent results in the preview: it is like the coordinates set up at full resolution are not being scaled to the preview size, but just calculated as absolute coordinates. So if i crop/offset a strip at 25% preview size, then in the final rendering i get unexpected results (the strip is not present, or just it placed not where it should be), and vice-versa: if i crop/offset at 100%, then i can't preview the movie at 25% because the PNG strips remain too big.

This does not happen if i offset/crop an effect strip, such as a Color one, for which the proxy preview is rendered correctly.

This is a huge issue because it's hard to sync audio and video if working at 100% with the preview being too slow.

Using Blender 2.63a on Windows 7 64bit, Studio XPS 16 (Core 2 Duo, Ati RV730, 8G DDR3, Catalyst 12.4).

Same issue on my friend's 13" MacBook (OSX, Core 2 Duo, Nvidia graphics).