Currently Being ModeratedNov 5, 2012 11:56 AM (in response to OlyInnovations)
I think you are correct. The specs for iPAD and iPhone say they only support H264, MPEG 4 and Motion JPEG none of which respect alpha channel.
Currently Being ModeratedNov 10, 2012 8:23 AM (in response to Jim Wanamaker)
Jim is correct. Codecs supported by iOS devices do not support alpha channels. No reason for them to.
Currently Being ModeratedJun 19, 2013 7:42 PM (in response to OlyInnovations)
It is true that no video codec under iOS supports an alpha channel. But, it is possible to use a 3rd party library to add this functionality into a specific iOS app. You would need to export to Quicktime with the Animation codec set to Millions+ and then prepare the video for inclusion into your iOS app. My blog post on the subject goes into detail if you are interested: