My app uses mergMP to list and play videos from the iPad library. This works fine for all videos except those downloaded from the iTunes store, which can be listed and selected but only generate a blank screen. (They play OK from the iPad's own Video app.)
Is there any workaround for this?
I have had issues with (song/video) files being listed as playable but that were not actually downloaded onto the device yet. Apples software will download them first and then play them if they are not already downloaded. To test out whether you are trying to play un-downloaded videos on the device: Go to "iTunes & App Stores" Settings in the Settings App on your iPad and then turn off "Show All Music" so that "Only music that has been downloaded to this device will be shown". Then try your app again. If it works then this is why they are not playing. If not then the problem must be elsewhere.
