Premultiplied Alpha

Hi, whats the right way to show premultiplied alpha bitmaps in avisynth? Code:

Can you clarify what you mean by premultiplied alpha? Only thing coming to mind: I forget offhand whether converting a YUV clip to RGB32 will set the alpha channel appropriately.

Different alpha blending methods: Example: Straight, Premultiplied and alpha channel Blending results (using VirtualDub Logo filter): **** (Overlay Pic/Blending method) **** Left: Premultiplied/Premultiplied or straight/straight Center: Premultiplied/Straight Right: Straight/Premultiplied 'Left' is the only correct blending. The script posted is intended for straight blending only. Premultiplied pics result in 'dark edges' (look center pic above) and need additional processing (dont know.. negative multiplication or something to brighten edges...).

There is no avisynth command allowing such per-pixel processing atm, right? Maybe a good solution would be to implement it directly in the 'layer' command... :sly: