View source for Gnash

'''[http://www.gnu.org/software/gnash/ Gnash]''' is a GNU Flash movie player and as a plugin to [[Browse]] is the default Flash player on the XO.  It is the free software counterpart to the [[Adobe Flash]] player. 

== About Flash ==

[http://en.wikipedia.org/wiki/Adobe_Flash Wikipedia] has a good overview of the various Flash technologies.   Flash animations and games typically have the .swf extension, while Flash videos typically use the .flv extension.  Flash technologies include the ActionScript virtual machine, as well as many proprietary codecs that are covered by patents.

== Differences between Gnash (XO) and Adobe Flash ==

Many flash applications and movies that work with Adobe Flash will not work on the XO.  This can be frustrating due to the large and growing base of animations, tutors, and other content available for Flash.  These include:
* [http://www.nortellearnit.org/ Nortel LearniT Collaborative Program] (pls confirm if it works/does not work)
* [http://www.eshikshaindia.in/ Shiksha Collaborative Learning Portal] from the Indian Industry Confederation

The Gnash team faces several challenges.  The primary challenge is the number of basic encoding schemes, such as MP3, that are covered by patents.  While Gnash supports these proprietary codecs, the OLPC cannot or will not ship codecs to support the proprietary schemes. As such, the version of Gnash that ships with the OLPC XO-1 has no sound playback by default. Another challenge is that Adobe had not provided full information about SWF files, though a recent [http://www.stanford.edu/class/ee380/Abstracts/061206.html Stanford class] and contributions to Mozilla's Tamarin project points towards some additional openness.  

Note that SWF files continue to evolve.  While Gnash provides good support for SWF version 7, support for later version is more challenging.  Gnash emulates Adobe Flash's Actionscript Virtual Machine 1 (AVM1 - used by Actionscript 1.0  and 2.0), but not Actionscript Virtual Machine 2 (AVM2) and thus cannot play Flash 9 & 10 content that has been authored in Actionscript 3.0.  Finally, Gnash depends on a number of rapidly evolving libraries, such as Gstreamer which hamper stability.

The easiest way to get Flash to work with Gnash is to get developers of the Flash content to test with Gnash. See also [[Projects/Flash_Gamedev|Game Development with Flash on the XO-1]].

== No sound in Gnash ==
Gnash requires additional software libraries for [[GStreamer]] to play sounds in .swf files (<trac>8504</trac>).  The relevant software has patent encumbrances, see [[Restricted formats]].  The issue persists in release [[10.1.2]].

It is possible to install packages containing the needed software using [[yum]] or [[rpm]]; the [[Talk:Gnash]] page has steps that have worked for users. In release [[8.2.0]] the task is made more complicated because it uses an earlier version of GStreamer.

== Gnash bugs ==

=== Gnash 0.8.3 (ships with [[Release notes/8.2.0|release 8.2.0]]) ===

==== <nowiki>[[</nowiki>Click to play]] is invisible ==== 
Unlike the Adobe Flash Player, Gnash doesn't immediately play Flash content (this is a feature).  You need to click its "<nowiki>[[</nowiki>Click to play]]" text.  But this text is often invisible when the mouse cursor is inside the Flash movie.

==== Other issues ====
* If sound is enabled, there are some sound incompatibility bugs when playing Flash 7 or 8 content
* Looping background sound in Flash Lite 2.0 (which is based on Flash 7) content plays back incorrectly. It breaks up with a lot of noise & hissing, and the volume levels change throughout sound playback.
* The onSoundComplete event does not seem to fire properly - thus sound that is looped using onSoundComplete as a trigger to start looping again will only play once and will not loop.

=== Gnash 0.8.2 (ships with release [[8.1.2]] (build 711)) ===
* _x, _y & _rotation problems when rendering fonts
* If sound is enabled, there are some sound incompatibility bugs when compared to Flash 7 & 8.

== Shipping Adobe Flash controversy ==

Adobe provides Flash under a free, but somewhat restrictive license.  Adobe's license clearly restricts any party besides Adobe from making Flash libraries available on the Internet, and may make it possible to distribute within an Intranet.  Some, such as Bryan Berry, have speculated that providing Flash plug-ins as downloads in certain deployments would further the educational goals of the overall project.

Other voices suggest that providing more incentives, better tools, and more complete implementations for Flash developers may help them to embrace open formats.  There is some undesirability of a long term dependence on a commercial entity for core functionality or core file formats.

=== Example videos ===
Playable in Gnash on the XO
*[http://www.youtube.com/ YouTube], part of the [http://www.google.com/corporate/tenthings.html Not-Evil Empire]

Playable on the XO using neither Gnash nor Flash
*[http://olpc.dailymotion.com Dailymotion] demos of new site

Not playable in Gnash on the XO
*[http://sesameworkshop.org/sesametreet/  Sesame Street Workshop] (including Elmo's World, etc)
*OLPC.TV
*[http://www.scribemedia.org/2008/02/20/greener-gadgets-jepsen/ Mary Lou Jepsen keynote] at [http://www.greenergadgets.com/ Greener Gadgets] Conference
*[http://www.blip.tv Blip.TV]
*[http://www.revver.com Revver.com]

== Upgrading Gnash == 

=== Enabling and disabling Gnash === 

You can uninstall or reinstall Gnash as you would any package: from the [[Terminal Activity]], [[sudo]] [[yum]] remove gnash -y or sudo yum install gnash -y After which you will want to [[reboot]]. 

=== Development builds === 
There are [[rpm]]s of later Gnash versions at http://www.getgnash.org.  Version 8.5 adds XVideo support, just add <tt>et XVideo true</tt> to your $HOME/.gnashrc file.  Some of these builds dynamically link ffmpeg to avoid problems with the non-standard [[GStreamer]] in 8.2.x releases.  See [http://www.mail-archive.com/devel@lists.laptop.org/msg19127.html mailing list message].

== Links ==

* [http://www.gnu.org/software/gnash/ Gnash homepage]
* Gnash mailing list : <tt>gnash-dev /at/ gnu.org</tt>

[[Category:Browser plugins]]