DASHR API

DASHR API allows you to take advantage of MPEG-DASH and stream it through HTML video tag.

No plugin to install.

It’s a requirejs module and it needs a browser supporting Media Source API in order to work.

How to use it :

dashr = require(‘AxthimaDASH/api’);

dashAPI = new dashr(video,mpd_src,events_handlers,preselectionned_tracks);

• video : the video element through which you want to display the video. You need to disable native controls and implement your own or it will behave strangely.

You can check out the wrapper we did for videojs : https://github.com/ISIA-DASHR/videojs-DASHR-tech

• mpd_src : the link to the manifest mpd. For supported Dash features, check out http://dashr.option-isia-ecp.fr/

• event_handlers : object containing callbacks functions

  exemple : {onMetaData : function…, onBuffering: function…, onFinish: function…}

  Explanations:

  • onMetaData(trackinfos) : called when metadata have been processed, gives an object containing tracks infos

  • onBuffering : is called when the video is buffering

  • onFinish : is called when the video is over

• preselectionned_tracks : allows you to choose with which adaption set and/or representation you want to start the playing exemple : { audio: {id_aset : 1, id_rep : 2}, video : {id_aset:0}} If you don’t use this parameter or don’t set something it will be chosen automatically.

This methods are then available on the dashAPI object :

• dashAPI.play()

• dashAPI.pause()

• dashAPI.paused() : tells you if the video is paused.

• dashAPI.getBuffered() : gives you a TimeRange-like object.

• switchRepresentation(type,id_aset,id_rep) : used to manually change a track.

That’s all for the moment.** Don’t forget to check out the wrapper we did for videojs on https://github.com/ISIA-DASHR/videojs-DASHR-tech**

MPD Generation :

First of all you need to create a proper mp4 file. And then you need to use mp4box to package to mpd

Here are the command line i used:

ffmpeg -i M2.h264 -vcodec libx264 -vprofile baseline -b:v 1300k -pix_fmt yuv420p -keyint_min 125 -g 125 -sc_threshold 0 -r 25 high.mp4 MP4Box -dash 5000 -rap -frag-rap -profile onDemand high.mp4

I'm not sure it's perfect but one point seems important to be working: you need keyint_min = g and g / framerate = dash_fragment_duration

In this case 125/25 = 5s which is what is specified for -dash

And -pix_fmt yuv420p is because it seems chrome only handle that pixel format

More over in order to work in chrome you need a rap in the beginning of each segment, it's why there is -rap and -frag-rap

Thanks To :

Google / Youtube for http://dash-mse-test.appspot.com/

DASH-JS http://www-itec.uni-klu.ac.at/dash/?p=792

GPAC http://gpac.wp.mines-telecom.fr/