Windows Phone: playing a recorded sound throws exception - windows-phone-8

Question

I am using an AudioVideoCaptureDevice to record some sound from the microphone. I want to give the user feedback on what he recorded so I want to be able to play it.
When putting that sound into a Song and playing it via Microsoft.Xna.Framework.Media.MediaPlayer, I am getting an exception:
{System.InvalidOperationException: Song playback failed.
Please verify that the song is not DRM protected.
DRM protected songs are not supported for creator games.
---> System.InvalidOperationException: An unexpected error has occurred.
--- End of inner exception stack trace ---
at Microsoft.Xna.Framework.Media.MediaQueue.Play(Song song)}
Looking into the details of the song in the watch, the IsProtected() seems to cause issues. (If playback works, I get correctly that the song is not protected.) I am using AAC and ACM codecs, both give same results.
I can play the song after closing and opening the view again, but have not found any related initialization that would explain this.
I also tried copying the file, in case some process was still holding a lock on it, still, there is no improvement, same with isolated storage.
After not closing app but re-entering view the song plays without problems.
How can I directly play the recorded audio without any problems?

Answer 1

I used the AudioRecorder sample from http://independentinnovation.net/blogs/independentinnovation/archive/2012/12/11/Windows-Phone-8-Audio-Recording-using-Windows.Phone.Media.Capture.aspx .
(Note: right now this link is not working, domain expired.. anyway, I used someone else's code.)
It turns out, that in the Record() function, a stream is opened, that in the Stop() function is never properly flushed and disposed.
I don't understand how this could have caused the problem, since I did copy the resulting file, just to make sure that all handles are valid.
Still, old handling was definitely wrong and new handling is a lot cleaner, and, btw, works.
public async void StopRecording()
{
try
{
if (dev != null)
{
await dev.StopRecordingAsync();
dev = null;
// these 2 lines I had to add
await recordingStream.FlushAsync();
recordingStream.Dispose();
}
var length = new System.IO.FileInfo(fileName).Length;
System.Diagnostics.Debug.WriteLine("Recorded " + fileName + " with length " + length);
}
catch (System.Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.ToString());
}
}
edit: to give credits, I found the answer I used here http://www.postseek.com/meta/9fddd403d0cde523a542be42b7a4b057