Add AAC as a default audio track

To be friendlier to mobile devices like Android tables and ipads, always
add an AAC audio track when there isn't one. This avoids issues with AC3
not being supported on most mobile devices due to patent trolling.
Add support for resolution in title

Using the height of the image, add a hint to the title about the
expected display resolution of the video. e.g. 480p, 1080p, 720p, 4k
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