defagos
commented
4 years ago Here is what I found. This may contain errors but should provide the necessary steps to investigate the problem further:
- It seems that, even if we do not make any forced panel reloads when playing, scrolling is reset to the first item regularly when playing a livestream, in the case of my livestream every ~10 seconds. My interpretation is that the panel observe the DVR window and reloads when it changes. To fix this issue it suffices to change the stream to an on-demand one.
- I thought that maybe using
AVDateRangeMetadataGroupinstead of time ranges would maybe solve the issue for DVR livestreams, but this is not the case.
The strategy:
- Create a very simple demo with
AVPlayerViewControllerand metadata (~10 segments). - Test with an on-demand stream and a livestream (open the panel, scroll to the right, wait).
- If there is an issue, then this is an
AVKitbug which we could report.
If we want to reduce the number of forced reloads, we still can test metadata only (not ranges) with the following condition:
if (! [[navigationMarkers valueForKeyPath:@"items"] isEqualToArray:[previousNavigationMarkers valueForKeyPath:@"items"]]) {
...
}
At the moment, there is no official
AVPlayerViewControllerAPI to update navigation markers and metadata displayed in the info panel. Updating them on the player item after the view controller has been loaded once does not work. Not only titles or images displayed will not change, but changes in the navigation marker timestamps will not be reflected.I use a workaround to force a panel refresh, but with the issue that the scrolling position is then reset. The current implementation checks if navigation markers did change (metadata and timestamps), event slightly, and if this is the case forces a reload.
This is probably too much with the current control we have over the info panel, as sometimes times might slightly change (when calculating them based on stream dates). If we assume that markers timestamps are quite constant, we might probably loosen up a bit the comparison so that this better work, e.g. by only comparing the relevant metadata and number of items. Only in such cases should we trigger a reload.