Hi there,

I read the Doc about Audio notes from

http://developer.anscamobile.com/partner/audionotes

and I found that

Cross-Platform

linear 16-bit signed little-endian .WAV works everywhere. MP3 is also supported everywhere. (Though see royalty concerns.) We would like to get AAC/MP4, but this may turn out to be problematic on Android. If anybody knows of an open source AAC decoder that is non-GPL, please let us know.

Is that mean the best file format are .wav and .mp3? What royalty concerns refering to? I found some wav files are royalty free from internet, can I use them in my apps?

Thanks in advance

Royalty free doesn't mean free. You pay a one time fee and then you're free to use them.
Beware though that the Royalty Free they are talking about isn't related to the MP3 royalty fee.

Thanks for your quick response seth.

Please let me clarify my questions more.

1. To suppose cross platform I should use .wav and .mp3 format?
2. If I paid for the audio file, i should be safe to use in my app? Or MP3 format is not royalty free?