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Formatting video for local playback
Generated by Clearspace on 2008-05-18-05:00
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Video codecs include MPEG-1 and MPEG-2 as used for DVDs, and the many extensions and implementations of
MPEG-4 such as WMV9, H.264, DivX, and so on. Common audio codecs include MP3, OGG, AAC, WMA, and AMR.
{*}Containers{*}
The separate data streams are almost always multiplexed (also referred to as 'muxed') together into one file,
facilitating delivery and playback of both video and audio stream as a single object. The data streams are packaged
in what is called a container file. You will likely already know several container types as filename extensions, such as
AVI which is an Audio Video Interleave container file.
The container also serves to present the streams to playback devices so that they remain synchronised on playback,
by linking positions in one stream to positions in the other; interleaving them. They also present the streams in a
standardised structure, with an index of the contained streams and other assorted metadata.
Simply recognising the container type also provides a good indication of the likely compression codecs used on
the data streams inside them, without reading the stream data from the container, once you know the compression
codecs supported within certain containers.For example, MP4 files are the MPEG-4 IsoMedia container, and from
that we can assume that the video stream uses a form of MPEG-4 compression with AAC compression for audio.
Similarly WMV files are Advanced Systems Format (ASF) containers using WMV video streams and WMA audio
streams. AVI files are Audio Video Interleave containers that use Video-For-Windows compatible codecs for video
streams and generally WAV or MP3 audio streams.
{*}Formatting video for Sony Ericsson phones{*}
This section contains specific details and recommendations on creating video content for Sony Ericsson phones that
will be stored and played from the phone's local memory (internal memory or a memory card). As such it is suitable
for any video content that does not require real-time delivery to the phone.
{*}Supported containers{*}
Sony Ericsson phones have very functional support for the IsoMedia container as 3GP and MP4. MP4 containers
support MPEG-4 video streams and several types of AAC audio stream. 3GP is a simplified version of the container
that is used primarily for low bandwidth applications such as streaming content; it has additional support for AMR
audio tracks and H.263 video, and support for LC-AAC. As AAC offers considerably greater audio quality than AMR,
and similarly MPEG-4 video implementations outperform H.263, MP4 is the recommended container format to use.
Within the container, Sony Ericsson phones support only one video stream and one audio stream.
Detailed specifications
For software developers, the relevant ISO specifications for MPEG-4 multimedia content in relation to
Sony Ericsson phones are:
• MP4 container - MPEG-4 Parts 12 & 14 / ISO 14496-12 & 14496-14.
• MPEG-4 Visual - MPEG-4 Part 2 / ISO 14496-2.
• MPEG-4 Audio - MPEG-4 Part 3 / ISO 14496-3.