I was using AVAudioPlayer to play multiple audio clips back to back but there was always a small silence between tracks and then i came to know of Finch, a library which uses OpenAL to play audio. with this the silence problem seems to be solved theoretically but then i found that it doesn't play m4a or any other compressed formats.
Now i am looking for an uncompressed audio format which would have relatively less file size (though uncompressed means that all of them should have almost same size) and a method to convert, i am also googling on afconvert in a mean while.