What happens when a segment is missing, such as when a particular segment fails to download. If a high-resolution segment is missing on the server (that is, the file is not present or has been removed), the AVE looks for a variant playlist associated with the high-resolution bit rate.
If a missing segment still cannot be found, the AVE cycles through all variants and bit rates to attempt to find the missing segment. If not found, it continues with the next segment in the current resolution or appropriate resolution depending on the failover algorithm and continues playing in that resolution.
If no alternatives can be found for a segment download, the PSDK triggers a CONTENT_ERROR error notification. This notification will contain an inner notification with the code DOWNLOAD_ERROR. If the stream with the problem is an alternate audio track, the PSDK generates the AUDIO_TRACK_ERROR error notification.
The PSDK will not continue to try a faulty server forever, if there are other servers that perform consistently better.
There is a documented limitation in the AVE failover strategy that says that the ABR control parameters are no longer taken into consideration once a failover scenario occurs. This is due to the fact that the failover mechanism is designed to use as backup streams any of the currently available playlists (regardless of their bit-rate profile). In other words, it is possible during a failover operation to actually have a profile switch (a change in the stream's bit-rate). If there is an error with either the playlist download or with the download of one of the segments, the ABR control parameters (such as min/max allowed bit-rate) are ignored.