Bug occur when embedding more than 15 mp3 players in a single Web page resource. Bug happen only on Firefox, not IE. Problem easy to duplicate using attached mp3 (see below).

When I click play button on any single small player, button change shape from > (play) to || (stop) as expected, and you see little white line indicating mp3 loading. But then usually nothing play! Or maybe you wait a long time, then something play. However if you move mouse to hover over || button, it play immediately! Then move mouse away, sound may play or may stop. If sound do play and you scroll player out of viewport, sound stop! But then sound resumes when player scrolled back into viewport.

My files are quite small mp3's encoded with Bit rate = 128 kpbs and Sample rate 44.100 kHz. Documentation say this should be OK for Moodle player, so I suspect file not the problem.

Amazing thing: it happen with 16 players, but never 15 (I tried with many different files).

To duplicate bug on demo.moodle.org: Upload a attached file to Features Demo course (id= 5) media folder. Then create new Web page resource in demo course (course id 5) toggle into HTML mode (<>) and paste the following code.

<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />
<a href="http://demo.moodle.org/file.php/5/media/xxxxx.mp3"></a><br />