--- a/src/twjit.c	Sat Jul 06 17:32:26 2024 +0000
+++ b/src/twjit.c	Sat Jul 06 21:31:16 2024 +0000
@@ -25,8 +25,7 @@
 /* create and destroy functions */
 
 struct twrtp_jibuf_inst *
-twrtp_jibuf_create(void *ctx, uint16_t quantum_ms, uint16_t clock_khz,
-		   struct twrtp_jibuf_config *config)
+twrtp_jibuf_create(void *ctx, struct twrtp_jibuf_config *config)
 {
 	struct twrtp_jibuf_inst *twjit;
 
@@ -35,14 +34,11 @@
 		return NULL;
 
 	twjit->ext_config = config;
-	twjit->ts_quantum = (uint32_t)quantum_ms * clock_khz;
-	twjit->quanta_per_sec = 1000 / quantum_ms;
-	twjit->ts_units_per_ms = clock_khz;
-	twjit->ts_units_per_sec = (uint32_t) clock_khz * 1000;
-	twjit->ns_to_ts_units = 1000000 / clock_khz;
 	twjit->state = TWJIT_STATE_EMPTY;
 	INIT_LLIST_HEAD(&twjit->sb[0].queue);
 	INIT_LLIST_HEAD(&twjit->sb[1].queue);
+	/* default of 8 kHz clock, 20 ms quantum */
+	twrtp_jibuf_set_ts_quant(twjit, 8, 20);
 
 	return twjit;
 }
@@ -53,3 +49,15 @@
 	msgb_queue_free(&twjit->sb[1].queue);
 	talloc_free(twjit);
 }
+
+/* basic housekeeping */
+
+void twrtp_jibuf_set_ts_quant(struct twrtp_jibuf_inst *twjit,
+			      uint16_t clock_khz, uint16_t quantum_ms)
+{
+	twjit->ts_quantum = (uint32_t) quantum_ms * clock_khz;
+	twjit->quanta_per_sec = 1000 / quantum_ms;
+	twjit->ts_units_per_ms = clock_khz;
+	twjit->ts_units_per_sec = (uint32_t) clock_khz * 1000;
+	twjit->ns_to_ts_units = 1000000 / clock_khz;
+}