Why are swiffy files without sound on iPads? According to Google, "Swiffy converts Flash SWF files to HTML5, allowing you to reuse Flash content on devices without a Flash player (such as iPhones and iPads)." - https://www.google.com/doubleclick/studio/swiffy/

But, if you check the "Supported features and browsers" - at https://www.google.com/doubleclick/studio/swiffy/gettingstarted.html - it turns out sound in swiffy files is "partially supported", which means not at all by Mobile Safari iOS 5, Android Browser 4.0.3 and  Firefox 15, but is supported (maybe only "partially", it's not clear), by Chrome 22, Safari 6.0, Internet Explorer 9 and Opera 12.

I have converted a few flash-movies-with-sound to swiffy and seems to me the Google table should be about "Supported features and operating systems". Swiffy files play, with sound, on all my Windows browsers (IE, FF, Chrome). But on an iPad,  using both Safari and Chrome, swiffy.html is dead silent.  

So the question is... does anyone know why it is that on iPads, regardless of the browser (or at least those two), swiffy sound cannot be heard and is there any solution? If there isn't, swiffy has been oversold as a means of "reusing Flash content on devices without a Flash player (such as iPhones and iPads)" if on those devices there's no sound. 

It's a mystery why Google hasn't figured out a way of having swiffy deliver sound on iPads through Chrome. So is the problem Apple's iOS, and why?
HTML audio has shaky compatibility across all the different browsers.

For this to work correctly, the audio would need to be converted into MP3, OGG and WAV formats. (in addition to converting the video, which different browsers prefer different formats, too)

In short, HTML audio and video is young, and a fuller experience will come once the standards mature, and the browsers homogenise format compatibility.