MP3 player

The multimedia filter embeds MP3 files in a streaming player made with Flash. The big MP3 player is used when an MP3 file is added as a resource e.g. Moodle Features Demo: MP3 file. The small player is used when an MP3 file is linked to from within a forum post or another resource or activity using the HTML editor.

MP3 player rates

To ensure that MP3 files are played at the correct rate, sample rates of 11, 22 or 44 kHz should be used. Constant Bit Rate (CBR) files are also recommended over Variable Bit Rate (VBR) files. Please note that sample and bit rates are not the same thing. See the two sections MP3 sample rates and MP3 bit rates below.

MP3 sample rates

Flash Player can produce undesirable results if the MP3 files are not encoded at a sample rate that is not a multiple of 11.025 kHz. In other words, the acceptable sample rates are:

11.025 kHz

22.050 kHz

44.100 kHz

MP3 bit rates

Flash player cannot play MP3 files with a bit rate higher than 128 kbps, which is the default bit rate for most MP3 encoders. For use on the web, lower bit rates are recommended because they download faster and take up less server disk space. Experiment with different bit rates to get the smallest file you can with acceptable sound quality. Common bit rates are:

32 kbps, mono - speech only

40 kbps, mono - music might sound OK

40 kbps, stereo - speech only

48 kbps, mono - some music sounds OK

48 kbps, stereo - speech only

56 kbps, stereo - some music sounds OK

64 kbps, stereo - most music sounds OK

MP3 encoders

Audacity is a popular, free audio editing tool. However it is not suitable for encoding MP3s for use with Flash Player at the default sample rate settings. At lower bit rates, it uses sample rates that are not a multiple of 11.025 kHz and the resulting MP3 files may either play at an incorrect speed, the chipmunk effect, or not play at all. See the Audacity documentation on how to set the sample rates.

Other free MP3 encoders:

SUPER - a Windows-only general media encoder that offers full control over media file parameters and supports all major audio and video file types.

If you have used an MP3 encoder with success across different operating systems and browsers for Flash Player, please post it here.

I use Amadeus Pro for both recording & editing; not freeware, but close. - w.taylor

Flash security settings

Security changes in Flash player 7 may result in the MP3 player not playing MP3 files hosted on a remote server. This issue may be resolved by writing a cross-domain policy for the remote server and/or each user changing their global security settings in the Flash player settings manager.

Cross-domain policy

To create a cross-domain policy, save the code below as crossdomain.xml and place the file at the root of the remote server.

<cross-domain-policy>
   <allow-access-from domain="www.yourmoodlesite.org" />
</cross-domain-policy>

Please refer to Macromedia - Developer Center: Security Changes in Macromedia Flash Player 7 for further details.

Global security settings

Please refer to Macromedia - Flash Player Help: Global Privacy Settings Panel.

MP3 player colours

theme/yourtheme/config.php contains options for changing the default colours (black, white and grey) of the MP3 player.

$THEME->resource_mp3player_colors = 
 'bgColour=000000&btnColour=ffffff&btnBorderColour=cccccc&iconColour=000000&'.
 'iconOverColour=00cc00&trackColour=cccccc&handleColour=ffffff&loaderColour=ffffff&'.
 'font=Arial&fontColour=3333FF';
/// With this you can control the colours of the "big" MP3 player 
/// that is used for MP3 resources.

$THEME->filter_mediaplugin_colors = 
 'bgColour=000000&btnColour=ffffff&btnBorderColour=cccccc&iconColour=000000&'.
 'iconOverColour=00cc00&trackColour=cccccc&handleColour=ffffff&loaderColour=ffffff&';
/// ...And this controls the small embedded player

MP3 playback options

theme/yourtheme/config.php contains options for changing the playback options of the MP3 player.

waitForPlay determines whether the MP3 file starts downloading as soon as the player appears on the page (waitForPlay=no), or whether the play button must be pressed before the MP3 file starts downloading (waitForPlay=yes).

autoPlay determines whether the MP3 player starts playing the MP3 as soon as the player appears on the page (autoPlay=yes), or whether it must be fully downloaded before playing (autoPlay=no).

buffer determines how many seconds of the MP3 file must be downloaded before the MP3 starts playing e.g. 10 seconds (buffer=10).

Default playback options

Big MP3 player: buffer=10&waitForPlay=no&autoPlay=yes
Small MP3 player: waitForPlay=yes&autoPlay=no

Inserting sounds into questions

In a forum, Joseph Rézeau offer this

There are various ways to insert links to media files in Moodle. You can

(1) insert a link which when clicked will open a new window activating your computer's default media player (e.g. quicktime, realaudio, windows media player, etc.)
(2) OR rely on the automatic insertion of the small Flash player built-in Moodle
(3) OR both!

The Filter for multimedia must be on and Flash enabled. The HTML editor needs to be active for the question content.

In the question text, type "Listen to this sound and select your answer."
Select by highlighting "this sound"
Click on the Insert Web Link button
Give the address of your MP3 file, either a web address or an internal address of a file located in the moodledata directory of your Moodle course.
Toggle HTML source and view the result, something like this: Listen to < a href="http://moodle/file.php/2/audio/trumpet.mp3" >this sound< /a > and say what you heard.
Now type in the rest of your question data, depending on its type (MCQ, short answer, etc.).
The result will look something like (3) in screen dump below.
The student has a choice of using the Flash player (with its minimum buttons) or clicking on the link, which will open the computer's default media player, with all its buttons.

(2) Method to get the Flash player only, and no link to open an external player

In the question text, type "Listen to this sound xxx and say what you heard."
Select xxx
Click on the Insert Web Link button
Give the address of your MP3 file, either a web address or an internal address of a file located in the moodledata directory of your Moodle course.
Toggle HTML source and view the result, something like this: Listen to < a href="http://moodle/file.php/2/audio/trumpet.mp3" >xxx< /a > and say what you heard.
Delete xxx
The result will look something like (2) in screen dump below.
The student can only use the Flash player.

Example of Quiz Question with Sound

Temporarily disable the MP3 player

You can surround your link with <nolink></nolink> tags to stop any kind of processing including the multimedia filters that create the MP3 player. This may be useful when linking to external MP3 files with characters in their name that Flash cannot understand.

Documentation