With PNG images, one can attach img.png, img@2x.png, and img@3x.png via assets and then load the correct one at runtime based on the device screen dimensions. In addition, the iTunes upload/download process will "slice" asset resources so that a large app that contains 1x, 2x, and 3x assets can avoid having to download 1x and 3x assets when running on a 2x device. What I am wondering is this, can videos attached to an app also take advantage of slicing so that the app need not download 3 sets of video resources in those cases where videos created for specific screen sizes are included in the app? I see that assets do contain a generic "data" type, but it seems to only be able to mark data files as differing in terms of the Metal API version.
1 Answers
So, I looked all around the internets but was unable to find anything on how to solve this tricky issue. In the end, I rolled my own custom solution that basically wraps the m4v video file and treats the binary file as a PNG image, so that it can be included in an iOS asset catalog. This makes it possible to load @2x or @3x assets on iPhone and use iPad specific video asset dimensions on an iPad while also supporting slicing. For a working example, take a peek at my AlphaOverVideo Framework on github, the Bloom demo shows the client side logic to decode from PNG and then load the decoded .m4v video into a looping player. This demo is cool because it shows off the slicing idea, but it also contains a full screen 1 to 1 pixel aspect video of a flower blooming that shows how amazing perfectly rendered video can look. If anyone is interested in the command line encoder, I uploaded it to github at PNGRewrap.
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