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?

  • 1
    The JavaScript library that swiffy relies on appears to not support sound on several browsers, at least as of the versions listed on the chart you linked. This question would be more appropriate on a Web coding/JavaScript/HTML5 site.
    – tubedogg
    Commented Apr 16, 2014 at 6:17
  • 1
    My point is that it seems not to be a question of browers but operating systems, i.e. in browsers on Windows there's sound and in browsers on iPads there's not. That's why I posed the question here. Also posed the question because there's not much info around on the issue.
    – user75823
    Commented Apr 16, 2014 at 16:44
  • Per the chart you linked it doesn't work on Android either, which Google controls along with Swiffy, so if they want to make it work on mobile you'd think it would at least work there. Again that would indicate an issue with the underlying JavaScript library which would be out of scope for this site.
    – tubedogg
    Commented Apr 16, 2014 at 18:37

1 Answer 1


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.

  • If it helps, in the code of a swiffy.html file with sound, I see "data:audio/mpeg;base64", indicating that the sound is mpeg encoded in base64. The sound in an swf is exported as mp3.
    – user75823
    Commented Apr 23, 2014 at 17:21
  • further to: buildingwebapps.blogspot.it/2012/04/…
    – user75823
    Commented Apr 24, 2014 at 5:59
  • That blog post seems to align with my own experiences of mp3 in iOS. I couldn't get mp3 to play, although WAV was fine. Like I said, support is messy. :/
    – wrossmck
    Commented Apr 25, 2014 at 8:44
  • I tried the solution suggested, here: ibm.com/developerworks/library/wa-ioshtml5 , see Listing 11. I added that script to a simple "Play" button actioncript in flash, exported as swiffy, and tested in Safari on an iPad. It played, with no sound, but at least I got "The operation could not be completed" in response.
    – user75823
    Commented Apr 25, 2014 at 13:05
  • Of course, that script loads an external audio file, while swiffy sound is embedded/encoded in the html file. ...Sigh.
    – user75823
    Commented Apr 25, 2014 at 13:12

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