Audio playback via JavaScript for iPad EPUB

I would like to play audio in my EPUB file for iPad. Audio should play and pause on click on an image.开发者_Python百科 The image should also change.

---

We use the following JS code that we saved as 'audio-player.js'.

var channel_max = 12;   // number of channels
audiochannels = new Array();
for (a=0;a<channel_max;a++) { // prepare the channels
    audiochannels[a] = new Array();
    audiochannels[a]['channel'] = new Audio(); // create a new audio object
    audiochannels[a]['finished'] = -1; // expected end time for this channel
}
function play_multi_sound(s) {

    for (a=0;a<audiochannels.length;a++) {
        thistime = new Date();
        if (audiochannels[a]['finished'] < thistime.getTime()) {            // is this channel finished?
            audiochannels[a]['finished'] = thistime.getTime() + document.getElementById(s).duration*1000;
            audiochannels[a]['channel'].src = document.getElementById(s).src;
            audiochannels[a]['channel'].load();
            audiochannels[a]['channel'].play();
            break;
        }
    }
}

Here is how you can use it:

Add the audio player js file:

<script src="../js/audio-player.js" type="text/javascript"/>

Add an audio tag to the body:

<audio id="storyAudio1" preload="auto" src="../audio/page_1.caf"/>

Add an image with an onClick event:

<img src="../images/play-button.png" class="audioButton"
onclick="play_multi_sound('storyAudio1')"/>

If you want to see a real example, download "Story Wheel" (http://www.storywheelapp.com/) (free), create a story, and then email yourself an ePub version of the story you just created.

We will be releasing an "auto play" version soon, which should work a bit better for us. Let me know what you think.

Andy

---

Not sure about the image part. You can use and tags in EPUB for iPad. Some good information can be found in Liz Castro's blog.