I tried solution given by stenlik and lighthu for descriptors (no file involved)
Everything works fine on emulator except (as known) loss of PCM 256 bytes on emulator.
But when i try same app on 6630, quality is bad. To debug the reason i tried 320 buffer size on emulator and i observed on emulator as well quality is bad if the size of the buffer given to CMdaAudioInputStream is kept 320.
I remember somebody also mentioned similar problem.
Looking for response from somebody who could able to resolve this issue.