When converting from RGBA to RGB, ffmpegcolorspace simply throws away alpha.<br><br>This is not compatible with videomixer, which uses "premultiplied" alpha.<br>In other words, the color components have been multiplied by alpha.<br>
<br>When using pre-multiplied alpha it is necessary to divide color values by alpha when converting back to regular rgb.<br><br>This is correct:<br> in: RGBA<br> out: rgb<br> action:<br> r = R/A<br> g = G/A<br>
b = B/A<br><br>But instead what actually happens is:<br> r = R<br> g = G<br> b = B<br><br>This problem is not specific to rgb but also happens in yuv.<br><br>I am willing to write some code to fix this. But ffmpegcolorspace has so many layers of macros that I am afraid to touch it.<br>
<br>Can someone advise me on an easy way to fix this?<br><br>Thanks much,<br>Bert Douglas<br><br><br>