Joel, while I couldn't find specific reference to it in the official IETF HLS spec, here's Apple's documentation on how backup streams are meant to be presented in the playlist files for use with iOS. It'd be helpful if Roku supported this as well, as I'm running across more and more providers that are using this standard.
Roku2 models do support HLS failover protection and will fallback to a backup stream with the same bitrate or, if no backup is available a lower bitrate variant.
Primary and backup streams should always be in sync, otherwise the failover protection does not work properly.
The Roku player should only access a backup stream if the primary stream failed to load.
If developers see different behavior they need to give us the steps to reproduce their issue and fix it (including a stream url we can test)
Matching content in variant streams MUST have matching timestamps.
This allows clients to synchronize the streams.
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