Encoding to other formats

Once a recording has been made with any of the available screencasting applications, it's often preferable to convert the video to another format, or use a different codec for distribution. Ubuntu for example is capable of playing OGG/Theora/Vorbis video out of the box. Other operating systems do not play OGG out of the box.

Containers

Numerous [http://en.wikipedia.org/wiki/Comparison_of_container_formats container formats] are available to put video and audio in. Of those, a small number are [http://en.wikipedia.org/wiki/Open_source_codecs_and_containers open source containers] and as such are appropriate for distribution to a free software user.

There is no container format yet that can contain a highly compressed data stream, and yet play on all platforms. Generally it is accepted that either the user should install the necessary software and/or codecs to play a video, or the content creator should make their video available in multiple formats.

Arguably everyone should just distribute OGGs as the container is not encumbered by patents that restrict the creation, distribution or use of content in this format. However if content creators wish to get a high degree of exposure to non-Linux users then they should make it very clear how to play OGGs on non-Linux platforms. This can pose problems for users who are not allowed to install software on their computers (for example in the work environment or in an internet cafe) and as such alternatives are often made available.

The most common container formats on the Linux platform are OGG and MPEG whereas on the Mac the MOV container has a high degree of penetration due to it being natively supported by the Mac media player - Quicktime. On the Windows platform ASF and the outdated AVI are very popular and play on most systems.

***** - Plays out of the box in supplied media player.

*** - Does not play out of the box, may require additional codec or player.

* - Non-free codec or player required to play.

Video Codecs

Audio Codecs

Conversion programs

Given the various containers and codecs used by the different screencasting applications and the above tables of supported codecs, it may be necessary to convert media to other formats. The scenarios below cover the major applications used for format conversion, and some sample scenarios.

• avidemux - Can read MPEG video and encode to many formats.
• ffmpeg2theora - Converts from anything that ffmpeg can read into OGG/Theora/Vorbis
• mencoder
• mogrify

Suggested Conversion options

From MPEG2 to H.264, H.263, MJPEG, MPEG4, VCD, DVD,

[http://fixounet.free.fr/avidemux/ avidemux]

From OGG to ..

From MPEG4 to OGG/Theora

{{{ffmpeg2theora mpeg4video.mp4 }}}

From AVI to Flash

{{{ffmpeg -i avifile.avi flashfile.flv }}}

=== From Flash to MPEG

{{{mencoder -oac mp3lame -ovc xvid -of avi -xvidencopts bitrate=1350 -o output.avi input.flv

• mencoder ffmpeg

}}}

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