Podcasting Compatibility Issues

Audio

Audio files come in a few different formats. MP3 is used almost universally as a high compression audio file format and can be used with most audio players. MP4 audio format may be the wave of the future, but there are, and will be a few compatibility issues in the months/years to come.

MP3 audio format is supported by Mac, Windows Media Player, Real Player, iPods and MP3 Players.

Video

Apple/Macintosh Quicktime, Microsoft Windows Media Player and and Real Player each has their own set of video formats that will not play on the other platforms.

Deciding which format to use is difficult. Each of the three most commonly used video platforms has built in limitations, preventing widespread use of a single file format.

It seems that the only way to provide maximum compatibility and accessibility to video files is to publish at least two different formats for each session published. In fact, UWTV uses 3 different formats (although they are not all working).

For iPod, Mac and Quicktime users - an MPEG-4 (.mp4) format seems appropriate. MPEG-4 may require upgrades to media software.

For windows users with Windows Media Player - plain old MPEG (.mpg) seems as good as any

iPod Podcasting Requirements

Allowed formats - m4a, mp3, mov, mp4, m4v, and pdf

H.264 video File formats: .m4v, .mp4, and .mov

Video: Up to 768 kbps, 320 x 240, 30 frames per second (fps),

Baseline Profile up to Level 1.3

Audio: AAC-LC up to 160 kbps, 48 Khz, stereo audio

MPEG-4 video File formats: .m4v, .mp4, and .mov

Video: Up to 2.5 mbps, 480 x 480, 30 fps,

Simple Profile Audio: AAC-LC up to 160 kbps, 48 Khz, stereo audio

Common AV Formats

Windows Media formats

File name extensions: .asf, .asx, .avi, .wav, .wax, .wma, .wm

Audio Visual Interleave

File name extension: .avi

Codec for WMP :

DivX codec

Cinepak codec

Indeo codec

DV codec

MJPEG codec

Uncompressed RGB or YUY2 codec

Moving Pictures Experts Group (MPEG)

File name extensions: m3u, mp2v, .mpg, .mpeg, .m1v, .mp2, .mp3, .m3u, .mpa, .mpe, mpv2
Note MPEG 2 requires third-party software or hardware decoders.

MPEG-4 (.mp4)

MPEG-4 is an International Standards Organization (ISO) specification that covers many aspects of multimedia presentation including compression, authoring and delivery. Although video compression and file container definition are two separate and independent entities of the MPEG-4 specification, many people incorrectly believe that the two are interchangeable. You can implement only portions of the MPEG-4 specification and remain compliant with the standard.

The MPEG-4 file format, as defined by the MPEG-4 specification, contains MPEG-4 encoded video and Advanced Audio Coding (AAC)-encoded audio content. It typically uses the .mp4 extension. Windows Media Player does not support the playback of the .mp4 file format. You can play back .mp4 media files in Windows Media Player when you install DirectShow-compatible MPEG-4 decoder packs. DirectShow-compatible MPEG-4 decoder packs include the Ligos LSX-MPEG Player and the EnvivioTV.

DVD Video

File name extension: .vob
Note DVD playback requires third-party software or hardware decoders and is supported only in Windows XP.

Musical Instrument Digital Interface (MIDI)

File name extensions: .mid, midi, .rmi

Apple Macintosh Audio Interchange File Format (AIFF) Resource

File name extensions: .aif, .aifc, .aiff

Sun Microsystems and NeXT

File name extensions: .au, .snd

Unix Audio (.au) files are UNIX-generated sound files

CD Audio Track

File name extensions: .cda

Intel Video File

File name extensions: .ivf
Note Intel Video File support requires the Intel Video 5.x codec.

Windows Media Player Skins

File name extensions: .wmz, .wms

Algebraic-Code-Excited Linear Prediction

UNIX

File name extensions: .au, .snd

QuickTime Content

File name extensions: .avi, .mov, .qt
Apple Computer developed the QuickTime file format to create, edit, publish, and view multimedia files. QuickTime format can contain video, animation, graphics, 3D and virtual reality (VR) content. Only QuickTime files version 2.0 or earlier can be played in Windows Media Player. Later versions of QuickTime require the proprietary Apple QuickTime Player. For more information, visit the Apple Web site

Macromedia Flash

File name extension: .swf
Note Playback of Shockwave Flash files requires the Macromedia Flash plug-in.

RealNetworks content

File name extension: .ra, .rm, .ram

RealNetworks content is created by software that is developed by RealNetworks. The content is compressed with proprietary RealVideo and RealAudio codecs and is stored in a file format developed by RealNetworks. To play RealNetworks content, obtain the RealOne player.

Windows Media Player Web page

Quicktime

Free Media Player Downloads

Apple QuickTime - .mov

Macromedia Flash 4 Player - Flash content .swf

Macromedia Shockwave Player - Shockwave content

Microsoft Windows Media Player - many

Real Player - .ra, .rv, .rm, .ram

Windows Media Player

Supported File Formats