I am stil having a bit of difficulty with mp3 sound player raters.
I would like to record at CD 44KHz and export to mp3s with a bit rate of 40bs. But moodle's flash multimedia plug in plays the mp3 file at double speed.
Michael Penney kindly advised that sampling rates of 22KHz work, and both he David Scotson kindly advised that I change the sample rate using Audacity.
When I halve the sampling rate to 22KHz then both Moodle and a standard MP3 player plays the file at half speed. This is harldly surprising. Halving the sampling rate, while keeping the same number of samples, will halve the speed.
However, when I halve the samping rate and then double the speed, the file plays at the correct speed on other MP3 players, but twice the speed on using the flash multimedia plug in.
Likewise if I double the speed and then half the sampling rater (reversing the order of operations) then the file still plays at teh correct speed on other Mp3 players but at double speed using the flash multimedia plug in.
And just for good measure, I tried halving the speed of the original file too, but that plays at half speed in both the flash mutlimedia player plugin and in other mp3 players.
Hmm...Perhaps I should try changing the speed of the mp3 file after export from audacity, using some other software. No. That did not work either. I doubled the speed of the reduced sample rate mp3 (column) 2 below using wavepad, so that it plays at the right speed in wave pad, but suddenly it plays at double speed in Moodles mp3.
It is very strange.
Please see the table below
Sampling Rate/ Bit Rate / Speed
Speed when playing using moodle multimedia filter
Speed when played using other MP3 players
44KHz / 40bs /normal
22Khz /40bs /normal
22Khz /40bs /double
22Khz /40bs /double
44KHz / 40bs / half
22KHz / 40bs / double
I don't know what other permutations I might try.
Any suggestions on what I might do?
Other players seems to be able to play the files at the right speed, and they are agreeing with each other. If you click the underlined file links in blue you can tests the files in other players. So this seems to be a bug in the flash player. Please can someone tell me who makes it so I can report it?