Hey all, Inside code switch_rtp.c file: static int rtp_common_read(switch_rtp_t *rtp_session, switch_payload_t *payload_type, switch_frame_flag_t *flags, switch_io_flag_t io_flags) ................ if (check || (bytes && !switch_test_flag(rtp_session, SWITCH_RTP_FLAG_USE_TIMER))) { if (!bytes && switch_test_flag(rtp_session, SWITCH_RTP_FLAG_USE_TIMER)) { /* We're late! We're Late! */ if (!switch_test_flag(rtp_session, SWITCH_RTP_FLAG_NOBLOCK) && status == SWITCH_STATUS_BREAK) { switch_cond_next(); continue; } return_cng_frame(); <------- this lane to return cng frame if late. } } Could someone explain why we want to return cng frame when package is late? this is caused for me to hear very bad noise audio. Can I disable return CNG frame? Cheers