success on the (video) alpha channel front
Posted: Tue Jul 22, 2014 10:58 pm
i had success exporting an image sequence with a premultiplied alpha channel from both blender and adobe premiere, retaining the alpha information in both cases. magic is able to read them perfectly.
i thought i'd write this down, incase it may be useful for somebody else.
Exporting from blender (2.71), i had success using the 'png' video codec (apparently this is also a video codec) which is available once avi, quicktime or matroska is chosen as container (under rendersettings>encoding), which one of those three container is selected doesnt seem to matter (you'll get an avi, mov or mkv file). once png is selected, 'rgba' becomes available in the menu above (rendersettings>output), which also needs to be selected. the video can then be exported.
From a premiere standpoint, i had only success with an avi container and 'none' codec (in the export settings>video). Then a 32-bit option becomes available, which seems to include the alpha channel. The video can be exported now. The disadvantage here: Those uncompressed files are quite big (40mb for ~1s of film). On the other hand this might come in handy with magic, as it wont have to decompress anything anymore and if your disk is fast enough (if i understood Eric correctly).
If you create your content in blender from the beginning, rendering as png image sequence or video sequence as described above, is not the only thing important. you'll also need to tick "transparent" under rendersettings>Film to make the "world background transparent with premultiplied alpha".
That's all, I hope this will be helpful.
i thought i'd write this down, incase it may be useful for somebody else.
Exporting from blender (2.71), i had success using the 'png' video codec (apparently this is also a video codec) which is available once avi, quicktime or matroska is chosen as container (under rendersettings>encoding), which one of those three container is selected doesnt seem to matter (you'll get an avi, mov or mkv file). once png is selected, 'rgba' becomes available in the menu above (rendersettings>output), which also needs to be selected. the video can then be exported.
From a premiere standpoint, i had only success with an avi container and 'none' codec (in the export settings>video). Then a 32-bit option becomes available, which seems to include the alpha channel. The video can be exported now. The disadvantage here: Those uncompressed files are quite big (40mb for ~1s of film). On the other hand this might come in handy with magic, as it wont have to decompress anything anymore and if your disk is fast enough (if i understood Eric correctly).
If you create your content in blender from the beginning, rendering as png image sequence or video sequence as described above, is not the only thing important. you'll also need to tick "transparent" under rendersettings>Film to make the "world background transparent with premultiplied alpha".
That's all, I hope this will be helpful.