This post discusses the use MP4Box, a multimedia packager to generate content conformant to the MPEG-DASH specification. MP4Box is a part of the tools bundled with GPAC, an open source multimedia framework used for academic and research purposes.
A cross platform framework, GPAC is developed at Telecom ParisTech as part of the research work of the Multimedia Group. The open-source project officially started in 2003 and is written in ANSI C as a flexible alternative to the MPEG-4 reference software.
GPAC is a full framework providing authoring tools, packagers, streamers and a multimedia player known as Osmo4. It covers different aspects of multimedia: A/V codecs, network protocols and synchronization management algorithms, scene representation tools, etc.
MP4Box and DASH
MP4Box, a command-line tool is used to segment or split media files among many other functions.Segmentation (-dash) is the process of creating segments, parts of an original file meant for individual/separate HTTP download. These segments are referred to in the XML file used to drive the HTTP Streaming. A segment can be part of a single file or made up of several files. Segment boundaries are also used as bitstream switching points.
For example using the following command
MP4Box -frag 10000 -dash 20000 -segment-name segment_file file.mp4
A file is segmented into 20 sec. segment files with 10 sec. fragments, this also created an associated XML file.mpd
A detailed documentation of MP4Box command line options is available online at https://gpac.wp.imt.fr/mp4box/dash/ or by typing MP4Box -h dash in the command line.
MP4Box can be obtained by download and installing GPAC.
The GPAC Installer for various OS is available here https://gpac.wp.imt.fr/downloads/
Here is a working example video of a media file dashed with MP4Box.
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