codem-isoboxer
Advanced tools
codem-isoboxer is a small browser-based MPEG-4 (ISOBMFF) parser. It is meant to be small, fast and efficient. A typical use-case would be inclusion in a new player framework (for emerging standards such as MPEG-DASH which rely on ISOBMFF for most situations) or to extract metadata from MPEG-4 files:
emsg boxes for in-band events;mdat boxes for extracting subtitles;Currently a limited set of ISOBMFF boxes is supported:
Support for more boxes can easily be added by adding additional box parsers in src/iso_box.js. Some utility functions are included to help with reading the various ISOBMFF data types from the raw file. Also, see the Box Support page on the Wiki for a full list.
A modern web browser with support for:
Include one of the files in the dist folder (regular or minified) in your web page/application:
<script type="text/javascript" src="iso_boxer.min.js"></script>
Then, you can parse a file by calling the parseBuffer function:
var parsedFile = ISOBoxer.parseBuffer(arrayBuffer);
console.log(parsedFile.boxes);
The arrayBuffer can be obtained for example by issuing an XMLHttpRequest with responsetype set to arrayBuffer, or by using
the FileReader API to read a local file.
codem-isoboxer makes no assumptions on the validity of the given file and/or segment. It also does minimal handling of the data
types and provides mostly a raw interface. Some frequently used attributes are parsed to easier-to-use types, such as the major
brand and list of compatible brands in the ftyp box.
For traversing the box structure you can use the _parent property. It returns exactly what you expect: the parent of the
current box. The opposite is the boxes property (only available on container boxes such as moov), which gives you its children.
Every box also has a _root property which returns the top-level (file) container.
Another way to use the software is to only retrieve the boxes you are interested in. This way you don't have to traverse the box structure yourself:
var parsedFile = ISOBoxer.parseBuffer(arrayBuffer); // Parse the file
var ftyp = parsedFile.fetch('ftyp'); // Fetch the first box with the specified type (`ftyp`)
var mdats = parsedFile.fetchAll('mdat'); // Fetch all the boxes with the specified type (`mdat`)
Traversal of the box structure is always depth first. Note that while you jump directly to a box using the fetch commands, the entire parsed structure is still available, so the _parent, _root and boxes properties are still available.
An additional utility method is included to convert DataViews into strings. This uses the TextDecoder interface is available,
otherwise it falls back to a naïve implementation (bytes to character codes). If the TextDecoder interface is available you can
supply an additional encoding parameter (defaults to utf-8) to the function.
var parsedFile = ISOBoxer.parseBuffer(arrayBuffer); // Parse the file
var mdat = parsedFile.fetch('mdat'); // Get the first 'mdat' box
var text = ISOBoxer.Utils.dataViewToString(mdat.data); // Convert the data into a string (e.g. captions)
Basic support for incomplete buffers is also available. Boxes and containers that cannot be fully parsed (due to an empty buffer)
will be marked with an _incomplete property. You can simply add new data to the ArrayBuffer when it becomes available and
re-parse the buffer.
Does it work in NodeJS? Well, it's really meant to be run in a web browser, but since Node supports most features it shouldn't be a problem. You can install it using NPM:
npm install codem-isoboxer
Then use it in your code (NodeJS v0.10.36 tested, 0.12.x should work as well):
var ISOBoxer = require('codem-isoboxer'),
fs = require('fs');
var arrayBuffer = new Uint8Array(fs.readFileSync('my_test_file.mp4')).buffer;
var parsedFile = ISOBoxer.parseBuffer(arrayBuffer);
Et voila. It does not support any of the fancy stream stuff from Node. Also, the Node console has some issues with printing objects that contain buffers/dataviews/circular references. It might not look pretty in the console, but it works.
Check out the source from Github. Make changes to the files in /src. We use grunt to build the distribution files. If you add a box parser be sure to include a comment that points toward the relevant section in the specs. And if at all possible add a (small!) file to test/fixtures to provide an example.
The test directory is not included in the published package on npmjs.org because of the included MPEG-4 files.
grunt
You can use grunt-contrib-watch to watch for changes to the source and automatically build it:
grunt watch
Included is a small set of tests which check the code against a known set of ISOBMFF files. The tests use NodeJS with jasmine-node.
Make sure you have the grunt watcher running, as it tests against the resulting build of the JavaScript files. Usage:
# npm install jasmine-node -g
# jasmine-node test/spec
When adding new parsers please consider adding an ISOBMFF test file and a relevant test spec.
Please note, for size concerns, tests are only included in the Github repository and not in the released packages on NPM.
Open test/index.html in your browser. Use the file picker to select a local MPEG-4 file to parse it. Results will be in the window.parsedFile variable. Inspect it from your browser's console. Some test files are included in test/fixtures (not included in the package published on npmjs.org).
codem-isoboxer is released under the MIT license, see LICENSE.txt.
codem-isoboxer 0.0.6 (2015/05/13) ##
_incomplete property)ssix box_root propertyFAQs
A lightweight JavaScript MP4 (MPEG-4, ISOBMFF) file/box parser.
The npm package codem-isoboxer receives a total of 66,227 weekly downloads. As such, codem-isoboxer popularity was classified as popular.
We found that codem-isoboxer demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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