void receive_originator(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len);
void receive_terminator(struct osmo_cc_session_codec *codec, uint16_t sequence_number, uint32_t timestamp, uint8_t *data, int len);
void call_media_handle(void);
void call_clock(int len);
void encode_l16(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len);
void decode_l16(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len);