Question

I am building an a/v html5 streaming web app. This question pretains to the audio portion of the project, but i’m sure i will run into a similar situation when i get started on the video portion. My target device is the iPad’s safari browser (hence why i have to do this html5). Playback works fine, but i have a loading bar which needs to reflect how much of the track has been loaded. Following the w3 spec, i tried to implement this the following way using jQuery:

var that = this;
that.player = $('audio')[0];

$('that.player').bind('progress',function(){
    var buffer = that.player.buffered.end(0)      
    that.updateLoadBuffer(buffer);
});

This did not work. ‘that.player.buffered’ returns a TimeRanges object, and TimeRanges have a method ‘end(index)’ which returns the playback position of end of the buffer in seconds for the TimeRange specified by ‘index.’ TimeRanges also have a .length property which tells you how many TimeRanges are encapsulated by the object. When i tried to log that property i found that TimeRanges.length = 0, meaning no TimeRanges are passed back. Also when i threw logging statements into the bound function, i found that the ‘progress’ event was never fired. I have separate functions for the ‘loadedmetata’ and ‘timeupdate’ events which follow a similar format, and those fire off as expected. I tried other methods for capturing events to no avail:

that.player.onprogress = function(e){
     console.log('progressEvent heard');
};

that.player.addEventListener('progress',progressHandler, false)
function progressHandler(e){
    console.log('progressEvent heard');
};

Neither of these triggered my console message. My audio tag declaration is as follows:

<audio style="width:0;height:0;"></audio>

what am i doing wrong here?

UPDATE: I am using wowzamediaserver to handle the http streaming. I dont know if that could have anything to do with it.

YET ANOTHER UPDATE: I realize i do not have a source in my audio tag, that is because i set it dynamically using jquery, as follows:

$('audio').attr('src','http://my.wowza.server:1935/myStreamingApp/_definst_/mp3:path/to/my/track/audio.mp3/playlist.m3u8');

again i am not having playback issues so this shouldn’t have any bearing on my problem, but i just want to give you guys as clear of a picture as possible.

Answer 1

The HTML5 specification is still a draft under development so browsers that support it are essentially conforming to a yet-to-be-finalized spec. As such I wouldn’t expect their HTML5 features to be fully functional…