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Archive for the ‘jAUs’ tag

motivation be damned, just wait for someone else to do it and sleep more

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So, a few weeks ago I said in these posts that I thought it was an oversight that the HTML5 audio and video elements didn't let one pass start and stop time parameters, allowing one to use specific portions of an audio or video file.

Well, I just saw on this page that Mozilla has implemented this functionality per the Media Fragments URI Specification. And it seems that Webkit is there, too, per this post from a few weeks ago. Actually, that post was published the same week as when I started fiddling with a pure JavaScript and "data-" attribute solution when I went home sick from work. Now I wish I had just napped more that day and just waited to learn more about these implementations to take place.

Know what's funny? I never saw these docs when I wrote the aforementioned posts. Perhaps that's because the pages I linked to above about Mozilla/Webkit were last updated within just a few days of mine. But anyway, I found them today because I saw someone came to my page searching for "<audio> starttime" and I wanted to see what else came up for that query so I "Googled" it. Sometimes it's educational and not just an exercise in vanity to know why people come to your site, huh?

ZZZ …

;)

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Written by nitin

February 7th, 2012 at 9:11 am

Posted in digital audio

Tagged with , ,

jAUs 3-D: no glasses required

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So, I am slightly obsessive compulsive.

I worked a little more tonight on this jAUs thing to add support for start and stop time attributes in the HTML5 <audio> tag.

Video should work, too, with a little work, but I don't care about that right now.

What I did tonight was make it so that if a "stopTime" attribute is used, then after that point is reached the player will move the scrubber back to the original "startTime" value though at that point the playback is already paused.

If there is no "stopTime" attribute, then after the file's played itself to the end, the scrubber will move back to the "startTime" value. Again, playback is already paused at that point.

I've tested this with Firefox 9.01, Internet Explorer 9, Safari 4.0.5, Opera 11.60, and Chrome 16.0.912.75 on my Windows 7 (32-bit) laptop.

Running everything from my desktop, I had no problems except that I should mention that if I used the "autoplay" attribute and set it to "true", Chrome didn't start the playback as it should, but it seems that maybe that's a Chrome problem that others are having, too.

Testing with the files uploaded to my hosted account was a different story. Opera seemed to need a page refresh before the scrubber would locate itself at the proper positions – though adding a pesky alert() at the beginning seemed to make Opera happy. Chrome and Safari seemed to take a few seconds to get situated, although they seemed to generally need a restart to move the scrubber to the right place for the last audio player. I didn't test the alert() thing for these two. Firefox did well although I hate the way Firefox moves the audio players around depending on whether the audio has been played or not. And that leaves IE9 … which, hands down, did the best. Maybe that's because of the exception I'd added for it as I mentioned in an earlier post.

So, there's still work to do and things to investigate.

Also, I haven't tested this with really long files or anything so I don't know how that would go. But then again, as I've heard others say, HTML5 media elements aren't really for long-form media anyway.

Oh yeah, one more thing. I did in fact change to "data-startTime" and "data-stopTime" to make the HTML legal HTML5.

Here's the HTML5 code itself, letting one see that the JavaScript has now been moved into a separate JS file.

<!DOCTYPE html>
<html>
  <head>
    <title>jAUs</title>
    <meta charset="UTF-8" />
  </head>
  <body>

  <script type="text/javascript" src="jAUs.js"></script>

  <p>This is the entire recording of Shakespeare's Sonnet 130, read by Nathan Miller for
  <a href="http://librivox.org/sonnet-130-by-william-shakespeare/">LibriVox</a>.</p>
  <audio controls>
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

  <p>"My mistress' eyes are nothing like the sun." - <em>start = 10; end = 13.</em></p>
  <audio class="jAUs" controls data-startTime="10" data-stopTime="13">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

  <p>"End of poem."- <em>start = 57, no end specified.</em></p>
  <audio class="jAUs" controls data-startTime="57">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

</body>
</html>

Oh, and here's the JavaScript file:

/*
***** Note: This software is still in ALPHA. Please refrain from using
the code without first contacting Nitin Arora at nitaro74@gmail.com.
Thanks!
***** 

jAUs: JavaScript <audio> Shark.

Copyright (c) 2012 Nitin Arora. 

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software. 

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 

jAUs is licensed under the MIT license:

http://www.opensource.org/licenses/mit-license.php.

*/

function jAUs(){

  audioTagArray = document.getElementsByClassName("jAUs");

  for (i=0;i<=audioTagArray.length-1;i++){
    var thisAudioTag = audioTagArray[i];
    jAUs_2(audioTagArray,thisAudioTag);
  }
}

function jAUs_2(audioTagArray,thisAudioTag){
  //if this is placed directly into jAUs() - i.e. not a separate function,
  //then this whole thing doesn't seem to work.

  if (navigator.appName == "Microsoft Internet Explorer"){
    thisAudioTag.onloadeddata = function(){
      var thisAudioTag_startTime = thisAudioTag.getAttribute("data-startTime");
      thisAudioTag.currentTime = thisAudioTag_startTime;
    }
  }

  else {
    var thisAudioTag_startTime = thisAudioTag.getAttribute("data-startTime");
    thisAudioTag.currentTime = thisAudioTag_startTime;
  }

  var thisAudioTag_stopTime = thisAudioTag.getAttribute("data-stopTime");
  var stopString = "jAUs_3(this.currentTime," + thisAudioTag_stopTime + "," + i + ");";
  //returns "jAUs_3(this.currentTime, 13, i);" where "i" is an int.

  thisAudioTag.setAttribute("ontimeupdate",stopString);
}

function jAUs_3(this_currentTime,thisAudioTag_stopTime,i){

  if (thisAudioTag_stopTime){
    //if there's a data-stopTime attribute then ...
    if (this_currentTime > thisAudioTag_stopTime){
      //... reset audio to data-startTime when data-stopTime is reached.
      audioTagArray[i].currentTime = audioTagArray[i].getAttribute("data-startTime");
      audioTagArray[i].pause();
    }
  }
  else if (audioTagArray[i].ended == true){
    //if there's no data-stopTime, move back to data-startTime when playback has ended.
    audioTagArray[i].currentTime = audioTagArray[i].getAttribute("data-startTime");
    audioTagArray[i].pause();
  }
}

window.onload = function(){
  jAUs();
}

Update, January 12, 2012: Turns out "jAUs" is the name for some robotic SDK and I'm not too crazy about that name anyway. So, I'm leaning toward "m(AUj)ulate" (pronounced like 'modulate') which would stand for something like "My Untimely Little Audio Tag Extender". The word "untimely" being, of course, a play on the fact that time is what this is all about. The parenthetical bit refers to "audio" (AU) and JavaScript (j).

And, yes, I care much more about the name/acronym than the script itself.

:P

Update, January 15, 2012: OK, this is interesting. If, for the source of the audio file, I actually use the audio files on the Archive.org site for the LibriVox recordings like so …

  <audio class="jAUs" controls data-startTime="10" data-stopTime="13">
    <source src="http://www.archive.org/download/sonnet_130_librivox/sonnet130_shakespeare_njm_64kb.mp3" type="audio/mp3" />
    <source src="http://www.archive.org/download/sonnet_130_librivox/sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

… then this seems to be working OK in all the browsers. Chrome seems, per casual observation, the slowest in terms of getting the scrubber moved to the appropriate points, but I guess this is progress.

Related to all this stuff I've been messing with, I found this: Consistent event firing with HTML5 video – Dev.Opera. But here, too, they use an alert() to notify the user that metadata is loaded using "onloadedmetadata", but in my tests it seems like the alert() function itself was what was fixing the inability of some browsers to set the current time as my script was instructing.

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Written by nitin

January 11th, 2012 at 7:55 pm

jAUs 2: just when you thought it was safe to go back to hating Internet Explorer

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Yesterday, I posted this about trying to add "startTime" and "stopTime" attributes to the HTML5 <audio> tag using each of the major desktop browsers' native HTML5 audio player.

If anyone read that post, it's clear I ran into some problems with Internet Explorer 9 when all the other HTML5 browsers seemed to be fine with my JavaScript.

Well, I updated that post today to reflect a possible solution. Possible in the sense that it works, but I don't know if it's the best – or even a good – solution to the IE problem.

It basically involved checking for IE as the user's browser and using the HTML5 media events to find the event that would make IE wait until the right time before trying to access the current time of the audio element. I also referred to this page on Microsoft's site in terms of checking for IE.

You can read that update here: http://blog.humaneguitarist.org/2012/01/09/jaus-trying-to-add-a-starttime-attribute-to-the-audio-tag#update011012.

Hooray for anchor tags – and shark repellent.

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Written by nitin

January 10th, 2012 at 3:27 pm

Posted in digital audio

Tagged with ,

jAUs: trying to add a startTime attribute to the audio tag

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I work up this morning feeling unwell, but I still went in to work for a few minutes to enable Remote Desktop as it had stopped working (was a Windows Firewall thing) …

Anyway, on the walk back home I started thinking about something I've wanted to play with for a while.

And that's seeing what it would take to add support for a "startTime" attribute for the HTML5 <audio> tag using a browser's built-in player. I think it's a real oversight that there isn't native support for passing the start and stop times in the <audio> and <video> tags themselves. Um, there isn't right?

Adding support for a "stopTime" attribute would, I think, require more than I'm willing to think about right now (I should be napping) because obviously that entails checking the current time against the point at which one would want the media to stop.

But adding a simple (and, yes, non-standard) "startTime" attribute inside the <audio> tag seems pretty easy – if you aren't using IE. Ugh.

As you can see in the code below there's an alert() that returns a null, but without it IE (version 9) won't set the audio players to the values in the "startTime" attributes. The other "major" browsers do fine without it. And, really, it can't be there because it's annoying as hell.

But I think this still points to the problem of each browser having its own player. Take Safari for instance. It doesn't natively show the current or total time of the track. Chrome doesn't show the total time.

Still think Flash is a bad thing?

:P

<!DOCTYPE html>
<html>
  <head>
    <title>jAUs</title>
    <script type="text/javascript">
      function jAUs(){
        var audioTag = document.getElementsByClassName('jAUs');
        for (i=0;i<=audioTag.length;i++){
          var audioTag_startTime = audioTag[i].getAttribute('startTime');
          alert('');
          audioTag[i].currentTime = audioTag_startTime;
        }
      }
    </script>
  </head>
<body onload="jAUs()">

  <audio class="jAUs" controls startTime="10">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

  <br />

  <audio class="jAUs" controls startTime="25">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

</body>
</html>

ps: If this ever turns into a little project of mine, it needs a decently cool name to keep my interest. "JS" for JavaScript and "AU" for audio mashed up equals "jAUs". I hope that isn't already taken within the JavaScript/HTML5 domain.

Update, January 09, 2012: Now that an hour has past and I finished watching "Thor & Loki: Blood Brothers", I figured out how to elegantly do the "stopTime" thing – well, at least I think it's better than what I was thinking earlier today!

So unlike in the code above, the JavaScript below only hits on one <audio> element (the one with an "id" value of "jAUs") and not all the ones with a "class" value of "jAUs". But the point is that this new code adds the "ontimeupdate" attribute to the <audio> tag and makes it run a function called stopper() that will stop the audio once the current time is greater than the designated stopping time.

Now, there's still work to do. For example, the code should test for the existence of the "stopTime" attribute before forcing the stopper() function to run, but that's no big deal. I also need to test doing this as above – i.e. hitting all <audio> tags with a "class" value of "jAUs" – and see how that works. And there's that pesky IE thing, too.

Anyway, this is working in the other "major" browsers 'far as I can tell.

<!DOCTYPE html>
<html>
  <head>
    <title>jAUs</title>
    <script type="text/javascript">
      function jAUs(){
        var audioTag = document.getElementById('jAUs');
        var audioTag_startTime = audioTag.getAttribute('startTime'); //returns "10"
        //alert(''); //no IE love this time, sorry!
        audioTag.currentTime = audioTag_startTime;
        var audioTag_stopTime = audioTag.getAttribute('stopTime');  //returns "20"
        var stopThis = "stopper(this.currentTime," + audioTag_stopTime + ");"; //returns "stopper(this.currentTime,20);"
        audioTag.setAttribute('ontimeupdate',stopThis); //sends current time and stopTime value to stopper()
      }
      function stopper(currentTime, stopTime){
        var audioTag = document.getElementById('jAUs');
        if (currentTime > stopTime){
          audioTag.pause(); //stops playback if the current time is greater than the stopTime value
        }
      }
    </script>
  </head>
  <body onload="jAUs()">

  <audio id="jAUs" controls startTime="10" stopTime="20">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

</body>
</html>

Update, January 09, 2012: I still don't like it, but it seems that the alert() line can go at the top of the jAUs() function and still allow all this to work on IE 9. At least that prevents an alert message for each <audio> tag within the page.

Update, January 10, 2012: Ah. Now, we might be getting somewhere. I don't know if it's just a band-aid fix, but if I add an "onloadeddata" bit for IE9 this actually seems to be working just fine. The problem was that IE didn't consider the <audio> element's properties to be accessible, thus giving me an "Invalid State Error" with a code number of 11 which is this, more or less: "An attempt was made to use an object that is not, or is no longer, usable." So, IE9 is taking a little longer than the other browsers in realizing what's what.

<!DOCTYPE html>
<html>
  <head>
    <title>jAUs</title>
    <script type="text/javascript">
      function jAUs(){
        audioTag = document.getElementById('jAUs'); //this is a global variable
        var audioTag_startTime = audioTag.getAttribute('startTime'); //returns "10"
        //alert(audioTag.readyState); //IE returns "0", other browsers "4"
        //alert(audioTag.readyState); //IE and others return "4"

        //needs to be for IE9 only ... I guess it waits until the audioTag is ready to go.
        if (navigator.appName == 'Microsoft Internet Explorer')
        {
          audioTag.onloadeddata = function() {
            audioTag.currentTime = audioTag_startTime;
          }
        }
        else {
          audioTag.currentTime = audioTag_startTime;
        }

        var audioTag_stopTime = audioTag.getAttribute('stopTime');  //returns "13"
        var stopThis = "stopper(this.currentTime," + audioTag_stopTime + ");";
        //returns "stopper(this.currentTime, 13);"

        audioTag.setAttribute('ontimeupdate',stopThis);
      }

      function stopper(currentTime, stopTime){
        if (currentTime > stopTime){
          audioTag.pause();
        }
      }
    </script>
  </head>
  <body onload="jAUs()">

  <audio id="jAUs" controls startTime="10" stopTime="13">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

</body>
</html>

Update, January 10, 2012: Hopefully (for you and me) this is the last update for a while. Hey, I'm still sick, jerk!

Anyway, this is a test for hitting on all <audio> tags with a class value of "jAUs".

<!DOCTYPE html>
<html>
  <head>
    <title>jAUs</title>
    <script type="text/javascript">
      function jAUs(){

        audioTagArray = document.getElementsByClassName('jAUs');

        for (i=0;i<=audioTagArray.length-1;i++){
          var thisAudioTag = audioTagArray[i];
          jAUs_2(audioTagArray,thisAudioTag);
        }
      }

      function jAUs_2(audioTagArray,thisAudioTag){
      //if this is placed directly into jAUs() - i.e. not a separate function,
      //then this whole thing doesn't seem to work.

        if (navigator.appName == 'Microsoft Internet Explorer'){
          thisAudioTag.onloadeddata = function(){
            var thisAudioTag_startTime = thisAudioTag.getAttribute('startTime');
            thisAudioTag.currentTime = thisAudioTag_startTime;
          }
        }

        else {
          var thisAudioTag_startTime = thisAudioTag.getAttribute('startTime');
          thisAudioTag.currentTime = thisAudioTag_startTime;
        }

        var thisAudioTag_stopTime = thisAudioTag.getAttribute('stopTime');
        var stopString = "jAUs_3(this.currentTime," + thisAudioTag_stopTime + "," + i + ");";
        //returns "jAUs_3(this.currentTime, 13, i);" where "i" is an int.

        thisAudioTag.setAttribute('ontimeupdate',stopString);
      }

      function jAUs_3(this_currentTime,thisAudioTag_stopTime,i){

        if (this_currentTime > thisAudioTag_stopTime){
          audioTagArray[i].pause();
        }
      }
    </script>
  </head>
  <body onload="jAUs()">

  <audio class="jAUs" controls startTime="10" stopTime="13">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

  <br />

  <audio class="jAUs" controls startTime="25" stopTime="26">
    <source src="sonnet130_shakespeare_njm.mp3" type="audio/mp3" />
    <source src="sonnet130_shakespeare_njm.ogg" type="audio/ogg" />
    Your browser does not support the audio element.
  </audio>

</body>
</html>

By the way, using the HTML5 "data-" prefix a la "data-startTime" would make the attribute(s) valid, though still not part of a standard per the <audio> tag specifically. But I guess the "data-" prefix is an acknowledgment of reality.

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Written by nitin

January 9th, 2012 at 12:29 pm

Posted in digital audio

Tagged with , ,

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