HTML5 audio on Android 2.1 / Opera Mobile 11

I'm trying to create a HTML5 page with embedded audio. The page has to work on a ZTE BASE Lutea smartphone (Android 2.1) with Opera Mobile 11. Audio format is MP3 but OGG would be fine, too. All files have to be stored local on the smartphones sdcard.

My problem: While audio plays fine when loaded from a webserver, it fails when files are local. This is definitely not a source path error. The audio file is preloaded and I can alert the correct audio duration. Then, when the audio play() method is called开发者_开发知识库, it throws me a MEDIA_ERR_DECODE.

This is always the same no matter if I use MP3, OGG or the original WAV file. Any idea why there is a decoding problem of local audio files?

EDIT: When I'm opening a local HTML page "file://localhost/sdcard/index.html" in Opera and the page embeds an audio "http://localhost/audio.mp3", it works. Of course I had to install a local webserver and this would be a very bad solution.

Why is the HTTP protocol needed to play an audio file, does something like a local sandbox exist on android?

EDIT: I found that the Video object is able to play local sounds without problems. Unfortunately it's useless to me because I need an invisible audio and in Opera Mobile there is no way to prevent the video from going fullscreen.

With PhoneGap, you should be able to play local audio.

Opera 12 has the same issue. If the audio is played from cache is not working. I am using appcache.

This worked on Firefox mobile, so we used that.