Yesterday I gave ST4 Build 1905 (that was the available build yesterday) another rehearsal room stress test 11 days after doing same with ST4 Beta build 1792.
- 1 x ST4 Host (iPad 9th Gen iOS 26.0.1), 3 x ST Clients (iPad 4th Gen iOS 16.7.12, iPad 9th Gen iOS 26.0.1), iPad Pro iOS 26.0.1).
- All lyrics timestamped.
- Autoscroll Highlight positions = Centered
- 1 client device using Local lyrics on some songs (no obvious correlation on this point, but mentioning it all the same).
Compared to my experience 11 days ago (Build 1792) where the lyric sheet syncing was near perfect over a period of 4 hours/15 songs, yesterday was a hot mess right from the first song. I re-tested this morning on Build 1920 with 2 x Client iPads and repro'd the issues I had observed to remove the "it was just a bad night last night" phenomenom 🙂
The issues observed were:
- Clients lyric sheet highlighting would regularly lag behind by up to 5-20 sec. (usually 1 timestamp but sometimes 2-3) and then suddenly jump to current position to catch up.
- Client AND Host devices would sometimes not scroll the lyric sheet page, or not scroll enough. As a result, highlighting would not stay 'centered' and sometimes the highlighting would even disappear off the bottom of the screen. When this occured, sometimes the lyric sheet had just stopped scrolling entirely, sometimes it was that it just wasn't scrolling enough and the highlighting would slowly end up further and further down the page until it was no longer visible.
As I mentioned, I re-ran a quick test this morning, repro'd the behaviour, and made videos that capture these issues across 3 full songs.
Analyzing the videos, and knowing the timestamp locations in the lyric sheets, what it feels like is occuring is that sometimes a Client is not getting a timestamp sync message from the Host, but then it usually (but not always) gets the next timestamp message and catches up. I recorded one instance where 3 timestamped were missed berfore it finally caught up. Is this possibly a pitfall of using UDP in communications (i.e. there is no confirmation of receipt of the message) in action?
LogFiles on both Client and Host don't show anything out of the ordinary. If I'm not mistaken on that, Peter, is there an opportunity to add (addditional) logging around things like Client latency exceeding a certain threshold (possibly only if it does so for more than a specific period of time?), or whatever mechasnism the lyric sheet timestamp syncing uses also having logging if some delta (i.e. a client goes more out of sync than is 'OK') is exceeded, etc.?
As the videos are 200MB-300MB each (I recorded repros running 3 full songs, 1 video per song) I've sent a support email with a link to logs, videos, lyric sheets and a walkthrough of each video highlighting 'error points'..