Some users have reported an issue in which video does not play properly in iTunes after the update to 9.1.1. In some cases, only audio will play while a black or white image is displayed in place of the video; video may play only in full screen; not “in a separate window.” In other cases, video is garbled or corrupt.
As described by Apple Discussions poster Roberto Riquelme:
“iTunes 9.1.1 plays videos only in Full Screen, but not ‘in a separate window,’ in the ‘artwork window’ or in the ‘iTunes window.’ I can always hear audio. Happens with TV series, movies and music videos
Potential workaround
Until a more permanent workaround is found, try minimizing then then restoring iTunes windows and check to see if video begins to play properly.
Similar issue? Please let us know.