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MP3 player: Difference between revisions

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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 [[Resources|resource]] e.g. [http://moodle.org/mod/resource/view.php?id=2296 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]].
{{Working with media}}
 
==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.


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 [[Resources|resource]]. 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 sample rates==
==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, 22.050 and 44.100 kHz are acceptable sample rates but it is recommended to  use only 44.100 kHz (for both, music and speech recordings). The reason is that using a lower sampling rate will have very little effect on the final mp3 file size (bit rates have a bigger impact) but quality will decrease noticeably.
 
* 11.025 kHz
 
* 22.050 kHz
 
* 44.100 kHz
 


==MP3 bit rates==
==MP3 bit rates==
Flash player 9 is no longer limited and can play audio files with the maximum MP3 bit rate, that is 320 kbps.
However, while Flash player is not limited anymore, it is  recommend to use only one of the following:


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:
-- 96 kbps for speech audio files (if file size is critical, 64 kbps could still be acceptable), as this will avoid having very low quality recordings.
 
* 32 kbps, mono - speech only


* 40 kbps, mono - music might sound OK
-- 128 kbps for music (but not higher than that, as most people cannot differentiate between a 128 kbps file and a higher one).


* 40 kbps, stereo - speech only
It is also recommended to always encode using "Joint stereo" (not "Stereo"), as this will either improve quality or reduce filesize.


* 48 kbps, mono - some music sounds OK
==Flash security and Cross domain policy==


* 48 kbps, stereo - speech only
Here are up to date articles on policy file changes in Flash 9 and 10 and on Cross domain policy file usage:


* 56 kbps, stereo - some music sounds OK


* 64 kbps, stereo - most music sounds OK
[http://www.adobe.com/devnet/flashplayer/articles/fplayer9_security.html Policy file changes in Flash Player 9 and Flash Player 10]


==MP3 encoders==
[http://www.adobe.com/devnet/flashplayer/articles/cross_domain_policy.html Cross-domain policy file usage recommendations for Flash Player]


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.
[http://www.adobe.com/devnet/articles/crossdomain_policy_file_spec.html Cross-domain policy file specification]


===Other free MP3 encoders:===
[http://www.adobe.com/devnet/flashplayer/articles/flash_player10_security_wp.html White paper: Adobe Flash Player 10 security]


* [http://www.videohelp.com/tools/SUPER?oldversions=1 SUPER] - a Windows-only general media encoder that offers full control over media file parameters and supports all major audio and video file types.
===MP3 Encoder===


If you have used an MP3 encoder with success across different operating systems and browsers for Flash Player, please post it here.
[http://lame.sourceforge.net/ LAME]s a high quality MPEG Audio Layer III (MP3) encoder licensed under the LGPL.


I use [http://www.hairersoft.com/AmadeusPro/AmadeusPro.html Amadeus Pro] for both recording & editing; not freeware, but close. - w.taylor
==MP3 player customisation==


==Flash security settings==
It is possible to customise the colours of the the MP3 player via CSS included in the theme. For example


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.
<code>
.mp3flowplayer_backgroundColor {color: #000000;}
</code>


===Cross-domain policy===
modifies the background colour, see http://flowplayer.org/documentation/skinning/controlbar.html?skin=default for more colour properties, any property that ends with '...Color' can be overridden via CSS.


To create a cross-domain policy, save the code below as ''crossdomain.xml'' and place the file at the root of the remote server.
For accessibility reasons it is not allowed to initiate an automatic playback.
 
<cross-domain-policy>
    <allow-access-from domain="www.yourmoodlesite.org" />
</cross-domain-policy>
 
Please refer to [http://www.macromedia.com/devnet/flash/articles/fplayer_security.html Macromedia - Developer Center: Security Changes in Macromedia Flash Player 7] for further details.
 
===Global security settings===
 
Please refer to [http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager02.html 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.
 
* <code>waitForPlay</code> determines whether the MP3 file starts downloading as soon as the player appears on the page (<code>waitForPlay=no</code>), or whether the play button must be pressed before the MP3 file starts downloading (<code>waitForPlay=yes</code>).
 
* <code>autoPlay</code> determines whether the MP3 player starts playing the MP3 as soon as the player appears on the page (<code>autoPlay=yes</code>), or whether it must be fully downloaded before playing (<code>autoPlay=no</code>).
 
* <code>buffer</code> determines how many seconds of the MP3 file must be downloaded before the MP3 starts playing e.g. 10 seconds (<code>buffer=10</code>).
 
'''Default playback options'''
 
* Big MP3 player: <code>buffer=10&waitForPlay=no&autoPlay=yes</code>
* Small MP3 player: <code>waitForPlay=yes&autoPlay=no</code>


==Inserting sounds into questions==
==Inserting sounds into questions==
[http://moodle.org/mod/forum/discuss.php?d=33335 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.
See [[Audio in Moodle]]
#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 <nowiki> < a href="http://moodle/file.php/2/audio/trumpet.mp3" >this sound< /a > </nowiki>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
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."
#In the question text, type "Listen to this sound xxx and say what you heard."
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[[Image:Quiz question MP3 example.JPG|thumb|center|Example of Quiz Question with Sound]]
[[Image:Quiz question MP3 example.JPG|thumb|center|Example of Quiz Question with Sound]]


== Temporarily disable the MP3 player ==
==Tips and tricks==
===Temporarily disable the MP3 player ===
* You can surround your link with <nowiki><nolink></nolink></nowiki> 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.
* You can surround your link with <nowiki><nolink></nolink></nowiki> 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.
:''TIP:''  Be careful with the no link tags or any user written HTML code.  The [[HTML editor]] may eliminate some of your work if you use the HTML editor in the future.  The HTML editor tries to tidy things up for the new user but this can frustrate an experienced user of HTML code.
:''NOTE:'' This does not work for something like the following inserted into a page resource.
<nowiki><nolink><a href="http://theExampleServer.com/file.php/55/mp3_2/mt16/The_file.mp3"> The_file.mp3</a></nolink></nowiki> , however you can stop the multimedia filter from showing when linking to files by adding ?forcedownload=1 to the end of the link.
==See also==
* [[Audio in Moodle]] for  links to audio MP3 encoders, audio programs, modules and plugins for Moodle
*[http://moodle.org/mod/forum/discuss.php?d=199218#p869558  Useful forum post regarding mp3s] (with thanks to Guillermo Madero S


*NOTE: This does not work for something like the following inserted into a "web page. (Add a resource > Compose a web page)
<nowiki><nolink><a href="http://theExampleServer.com/file.php/55/mp3_2/mt16/The_file.mp3"> The_file.mp3</a></nolink></nowiki>


==See also==


* Using Moodle [http://moodle.org/mod/forum/discuss.php?d=43297 Multimedia resource filtering on the course page] forum discussion
* Using Moodle [http://moodle.org/mod/forum/discuss.php?d=14663 mp3 player rates] forum discussion
* [[Audio in Moodle]]
* [[Podcasting]]


[[Category:Administrator]]
[[Category:Administrator]]
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[[Category:Filter]]
[[Category:Filter]]
[[Category:Audio]]
[[Category:Audio]]
[[pl:Odtwarzacz_MP3]]
[[pl:Odtwarzacz_MP3]]
[[ja:MP3プレイヤー]]

Latest revision as of 20:35, 28 March 2012


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. 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 sample rates

11.025, 22.050 and 44.100 kHz are acceptable sample rates but it is recommended to use only 44.100 kHz (for both, music and speech recordings). The reason is that using a lower sampling rate will have very little effect on the final mp3 file size (bit rates have a bigger impact) but quality will decrease noticeably.

MP3 bit rates

Flash player 9 is no longer limited and can play audio files with the maximum MP3 bit rate, that is 320 kbps. However, while Flash player is not limited anymore, it is recommend to use only one of the following:

-- 96 kbps for speech audio files (if file size is critical, 64 kbps could still be acceptable), as this will avoid having very low quality recordings.

-- 128 kbps for music (but not higher than that, as most people cannot differentiate between a 128 kbps file and a higher one).

It is also recommended to always encode using "Joint stereo" (not "Stereo"), as this will either improve quality or reduce filesize.

Flash security and Cross domain policy

Here are up to date articles on policy file changes in Flash 9 and 10 and on Cross domain policy file usage:


Policy file changes in Flash Player 9 and Flash Player 10

Cross-domain policy file usage recommendations for Flash Player

Cross-domain policy file specification

White paper: Adobe Flash Player 10 security

MP3 Encoder

LAMEs a high quality MPEG Audio Layer III (MP3) encoder licensed under the LGPL.

MP3 player customisation

It is possible to customise the colours of the the MP3 player via CSS included in the theme. For example

.mp3flowplayer_backgroundColor {color: #000000;}

modifies the background colour, see http://flowplayer.org/documentation/skinning/controlbar.html?skin=default for more colour properties, any property that ends with '...Color' can be overridden via CSS.

For accessibility reasons it is not allowed to initiate an automatic playback.

Inserting sounds into questions

See Audio in Moodle

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

  1. In the question text, type "Listen to this sound xxx and say what you heard."
  2. Select xxx
  3. Click on the Insert Web Link button
  4. 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.
  5. 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.
  6. Delete xxx
  7. The result will look something like (2) in screen dump below.
  8. The student can only use the Flash player.
Example of Quiz Question with Sound

Tips and tricks

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.
TIP: Be careful with the no link tags or any user written HTML code. The HTML editor may eliminate some of your work if you use the HTML editor in the future. The HTML editor tries to tidy things up for the new user but this can frustrate an experienced user of HTML code.
NOTE: This does not work for something like the following inserted into a page resource.

<nolink><a href="http://theExampleServer.com/file.php/55/mp3_2/mt16/The_file.mp3"> The_file.mp3</a></nolink> , however you can stop the multimedia filter from showing when linking to files by adding ?forcedownload=1 to the end of the link.

See also