MPEG DASH Adaptive Streaming
Specifications
MPEG DASH is MPEG's standardized Adaptive Streaming over HTTP. It is specified in the following international standards:
ISO/IEC 23009-1 specifies the overall DASH architecture and the XML syntax for the MPD (Media Presentation Document)
ISO/IEC 23001-7 specifies the Common Encryption for MP4 fragments
ISO/IEC 14496-12/AMD 3 specifies the extensions to 14496-12 that are necessary to support DASH with fragmented MP4 media
Fragmenting MP4 files
To create DASH MP4 content, you need to start with fragmented MP4 files.
The command line tool mp4info can tell you if an MP4 file is fragmented or not: here's an example of what you will see in the 'Movie:' part of the mp4info output for a non-fragmented MP4 file (the line "fragments: no")
...
Movie:
duration: 147188 ms
time scale: 2997
fragments: no
Found 2 Tracks
...
If you have non-fragmented MP4 files, you can use mp4fragment to fragment them.
Example
mp4fragment somefile.mp4 somefile-fragmented.mp4
Generating the MPD
Once you have fragmented MP4 files, you need to create an MPD. For single-bitrate streaming, a single MP4 file is required. For multi-bitrate streaming, you will need a set of MP4 files that have been encoded with closed GOPs (Group Of Pictures) with equal durations. Also, the audio track in all the files should be encoded with the same parameters. Once you have your input files, you can use the python script mp4-dash.py (located under Source/Python/utils) to automatically generate the DASH MPD and optionally split the MP4 file into individual file segments. This script needs to invoke the Bento4 command line binaries mp4dump, mp4encrypt, mp4info, and mp4split compiled from the source, so you'll need to use the '--exec-dir' option to specify the directory where your built binaries reside (platform dependent).
If you just run the 'mp4-dash.py' script by itself, it will print out the options that are supported:
Usage: mp4-dash.py [options] <media-file> [<media-file> ...]
Each <media-file> is the path to a fragmented MP4 file, optionally prefixed
with a stream selector delimited by [ and ]. The same input MP4 file may be
repeated, provided that the stream selector prefixes select different streams.
Version 1.4.0 r557
Options:
-h, --help show this help message and exit
--verbose Be verbose
--debug Print out debugging information
-o <output-dir>, --output-dir=<output-dir>
Output directory
-f, --force Allow output to an existing directory
--init-segment=<filename>
Initialization segment name
-m <filename>, --mpd-name=<filename>
MPD file name
--no-media Do not output media files (MPD/Manifests only)
--rename-media Use a file name pattern instead of the base name of
input files for output media files.
--no-split Do not split the file into individual segment files
--use-segment-list Use segment lists instead of segment templates
--use-segment-template-number-padding
Use padded numbers in segment URL/filename templates
--use-segment-timeline
Use segment timelines (necessary if segment durations
vary)
--min-buffer-time=<duration>
Minimum buffer time (in seconds)
--max-playout-rate=<strategy>
Max Playout Rate setting strategy for trick-play
support. Supported strategies: lowest:X
--language-map=<lang_from>:<lang_to>[,...]
Remap language code <lang_from> to <lang_to>. Multiple
mappings can be specified, separated by ','
--smooth Produce an output compatible with Smooth Streaming
--smooth-client-manifest-name=<filename>
Smooth Streaming Client Manifest file name
--smooth-server-manifest-name=<filename>
Smooth Streaming Server Manifest file name
--hippo Produce an output compatible with the Hippo Media
Server
--hippo-server-manifest-name=<filename>
Hippo Media Server Manifest file name
--encryption-key=<KID>:<key>
Encrypt all audio and video tracks with AES key <key>
(in hex) and KID <KID> (in hex). Alternatively, the
<key> can be specified as the character '#' followed
by a base64-encoded key seed.
--encryption-args=<cmdline-arguments>
Pass additional command line arguments to mp4encrypt
(separated by spaces)
--use-compat-namespace
Use the original DASH MPD namespace as it was
specified in the first published specification
--marlin Add Marlin signaling to the MPD (requires an encrypted
input, or the --encryption-key option)
--playready Add PlayReady signaling to the MPD (requires an
encrypted input, or the --encryption-key option)
--playready-header=<playready-header>
Add a PlayReady PRO element in the MPD. The use of
this option implied the --playready option.The
<playready-header> argument can be either: (1) the
name of a file containing a PlayReady XML Rights
Management Header (<WRMHEADER>) or a PlayReady Header
Object (PRO) in binary form, or (2) the character '#'
followed by a PlayReady Header Object encoded in
Base64, or (3) one or more <name>:<value> pair(s)
(separated by '#' if more than one) specifying fields
of a PlayReady Header Object (field names include
LA_URL, LUI_URL and DS_ID)
--playready-add-pssh Store the PlayReady header in a 'pssh' box in the init
segment(s)
--exec-dir=<exec_dir>
Directory where the Bento4 executables are located
Specifications
MPEG DASH is MPEG's standardized Adaptive Streaming over HTTP. It is specified in the following international standards:
ISO/IEC 23009-1 specifies the overall DASH architecture and the XML syntax for the MPD (Media Presentation Document)
ISO/IEC 23001-7 specifies the Common Encryption for MP4 fragments
ISO/IEC 14496-12/AMD 3 specifies the extensions to 14496-12 that are necessary to support DASH with fragmented MP4 media
Fragmenting MP4 files
To create DASH MP4 content, you need to start with fragmented MP4 files.
The command line tool mp4info can tell you if an MP4 file is fragmented or not: here's an example of what you will see in the 'Movie:' part of the mp4info output for a non-fragmented MP4 file (the line "fragments: no")
...
Movie:
duration: 147188 ms
time scale: 2997
fragments: no
Found 2 Tracks
...
If you have non-fragmented MP4 files, you can use mp4fragment to fragment them.
Example
mp4fragment somefile.mp4 somefile-fragmented.mp4
Generating the MPD
Once you have fragmented MP4 files, you need to create an MPD. For single-bitrate streaming, a single MP4 file is required. For multi-bitrate streaming, you will need a set of MP4 files that have been encoded with closed GOPs (Group Of Pictures) with equal durations. Also, the audio track in all the files should be encoded with the same parameters. Once you have your input files, you can use the python script mp4-dash.py (located under Source/Python/utils) to automatically generate the DASH MPD and optionally split the MP4 file into individual file segments. This script needs to invoke the Bento4 command line binaries mp4dump, mp4encrypt, mp4info, and mp4split compiled from the source, so you'll need to use the '--exec-dir' option to specify the directory where your built binaries reside (platform dependent).
If you just run the 'mp4-dash.py' script by itself, it will print out the options that are supported:
Usage: mp4-dash.py [options] <media-file> [<media-file> ...]
Each <media-file> is the path to a fragmented MP4 file, optionally prefixed
with a stream selector delimited by [ and ]. The same input MP4 file may be
repeated, provided that the stream selector prefixes select different streams.
Version 1.4.0 r557
Options:
-h, --help show this help message and exit
--verbose Be verbose
--debug Print out debugging information
-o <output-dir>, --output-dir=<output-dir>
Output directory
-f, --force Allow output to an existing directory
--init-segment=<filename>
Initialization segment name
-m <filename>, --mpd-name=<filename>
MPD file name
--no-media Do not output media files (MPD/Manifests only)
--rename-media Use a file name pattern instead of the base name of
input files for output media files.
--no-split Do not split the file into individual segment files
--use-segment-list Use segment lists instead of segment templates
--use-segment-template-number-padding
Use padded numbers in segment URL/filename templates
--use-segment-timeline
Use segment timelines (necessary if segment durations
vary)
--min-buffer-time=<duration>
Minimum buffer time (in seconds)
--max-playout-rate=<strategy>
Max Playout Rate setting strategy for trick-play
support. Supported strategies: lowest:X
--language-map=<lang_from>:<lang_to>[,...]
Remap language code <lang_from> to <lang_to>. Multiple
mappings can be specified, separated by ','
--smooth Produce an output compatible with Smooth Streaming
--smooth-client-manifest-name=<filename>
Smooth Streaming Client Manifest file name
--smooth-server-manifest-name=<filename>
Smooth Streaming Server Manifest file name
--hippo Produce an output compatible with the Hippo Media
Server
--hippo-server-manifest-name=<filename>
Hippo Media Server Manifest file name
--encryption-key=<KID>:<key>
Encrypt all audio and video tracks with AES key <key>
(in hex) and KID <KID> (in hex). Alternatively, the
<key> can be specified as the character '#' followed
by a base64-encoded key seed.
--encryption-args=<cmdline-arguments>
Pass additional command line arguments to mp4encrypt
(separated by spaces)
--use-compat-namespace
Use the original DASH MPD namespace as it was
specified in the first published specification
--marlin Add Marlin signaling to the MPD (requires an encrypted
input, or the --encryption-key option)
--playready Add PlayReady signaling to the MPD (requires an
encrypted input, or the --encryption-key option)
--playready-header=<playready-header>
Add a PlayReady PRO element in the MPD. The use of
this option implied the --playready option.The
<playready-header> argument can be either: (1) the
name of a file containing a PlayReady XML Rights
Management Header (<WRMHEADER>) or a PlayReady Header
Object (PRO) in binary form, or (2) the character '#'
followed by a PlayReady Header Object encoded in
Base64, or (3) one or more <name>:<value> pair(s)
(separated by '#' if more than one) specifying fields
of a PlayReady Header Object (field names include
LA_URL, LUI_URL and DS_ID)
--playready-add-pssh Store the PlayReady header in a 'pssh' box in the init
segment(s)
--exec-dir=<exec_dir>
Directory where the Bento4 executables are located
