How can merge two sounds and save as a new file?. One sound is a loaded mp3 file and the other from the microphone. Then I need to upload this sound into a server. Is this possible?
This all can be done, but if you looking simple example with few methods to call, I'm afraid it's not so easy.
You can extract bytes from sound with Sound.extract(). This data is sound amplitude in 16-bit numbers, right and left channel interleaved. Use ByteArray.readShort() to get them.
Microphone data can be captured with SampleDataEvent.SAMPLE_DATA, see example here. To mix them with song, just add sound amplitudes and write result into third array. The result will be essentially WAV-format (without header,) unpacked sound data. You can upload it raw, or search for "as3 mp3 encoder" (google), but these things are rare and written by entusiasts, so maybe you can get them work. Also, to mix sounds correctly, frequencies of data from mic and sound file must be equal.
And upload part - if this was file on disk, this would be easy - FileReference.upload(). But there's only data in memory. So you can look into Socket class to send it.
来源：https://stackoverflow.com/questions/11013227/merge-two-sound-files-into-a-new-file