Hi, digging into the pjsip source code, wavplayer files, here are the cases in which the error PJMEDIA_EWAVEUNSUPP would occur: - Must be PCM with 16 bits per sample - Block align must be 2*nchannels - Invalid file length (wavehdr.data_hdr.len > fport->fsize_list[index] - fport->start_data_list[index]) - WAV playlist error: file '%s' has differrent number" of channels, sample rate, or bits per sample The files are wav_player.c and wav_playlist.c if you want to have a look. Hope this helps. Chris -- *Chris Scheid* Mobile Developer AppGuard LLC *"Safety for the Connected World"* *www.appguard.us <https://www.appguard.us>*