webPlayer no longer playing FLACs

<previously posted to the "General" forum, guessing should have posted here>
FLACs play fine on IOS and Android clients (transcoded into mp3). only configuration change that I can recall, was recent upgrade to 5.3 (build 4569). I'm running server on Windows 7. Don't have any mp3 loaded, though I should probably try that, just for fun.
Webplayer worked recently (and I've been using it for years), not absolutely sure if upgrade is culprit, but I suspect timing is right. This is new problem. I've tried webplayer on multiple machines: OS X 10.11 and 10.10, Win 8, on the Win 7 server... and multiple browsers: chrome, safari, IE same result on all platforms. I've even tried a couple desktop clients (e.g., clementine). and tried sharing via a URL. none of these options work. It does play jukebox mode, strangely.
Webplayer behavior is songs will download but will not play. Looking in the log, no errors, just "playQueueInputStream..." I did have problem after upgrading that lead me to trunc the database tables... it had stopped recognizing new files added to the directory. The rebuild fixed that... but maybe this somehow caused problem?
Any ideas?
FLACs play fine on IOS and Android clients (transcoded into mp3). only configuration change that I can recall, was recent upgrade to 5.3 (build 4569). I'm running server on Windows 7. Don't have any mp3 loaded, though I should probably try that, just for fun.
Webplayer worked recently (and I've been using it for years), not absolutely sure if upgrade is culprit, but I suspect timing is right. This is new problem. I've tried webplayer on multiple machines: OS X 10.11 and 10.10, Win 8, on the Win 7 server... and multiple browsers: chrome, safari, IE same result on all platforms. I've even tried a couple desktop clients (e.g., clementine). and tried sharing via a URL. none of these options work. It does play jukebox mode, strangely.
Webplayer behavior is songs will download but will not play. Looking in the log, no errors, just "playQueueInputStream..." I did have problem after upgrading that lead me to trunc the database tables... it had stopped recognizing new files added to the directory. The rebuild fixed that... but maybe this somehow caused problem?
Any ideas?