diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index c628e60f0a..04fd57e02b 100644
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -798,7 +798,8 @@ struct chan_iax2_pvt {
 	unsigned short peercallno;
 	/*! Negotiated format, this is only used to remember what format was
 	    chosen for an unauthenticated call so that the channel can get
-	    created later using the right format */
+	    created later using the right format. We also use it for
+		authenticated calls to check the format from __get_from_jb. */
 	iax2_format chosenformat;
 	/*! Peer selected format */
 	iax2_format peerformat;
@@ -4217,10 +4218,24 @@ static void __get_from_jb(const void *p)
 			 * In this case, fall back to using the format negotiated during call setup,
 			 * so we don't stall the jitterbuffer completely. */
 			voicefmt = ast_format_compatibility_bitfield2format(pvt->peerformat);
+			if (!voicefmt) {
+				/* As a last resort, we can use pvt->chosenformat.
+				 * This is set when we receive a call (either authenticated or unauthenticated),
+				 * so even if we haven't received any voice frames yet, we can still use the
+				 * right format.
+				 *
+				 * If we have to do this, in most cases, we aren't even processing voice frames
+				 * anyways, it's likely a non-voice frame. In that case, the format doesn't
+				 * really matter so much, because we could just pass 20 to jb_get instead
+				 * of calling ast_format_get_default_ms. However, until jb_get returns,
+				 * we don't actually know what kind of frame it is for sure, so use
+				 * the right format just to be safe. */
+				voicefmt = ast_format_compatibility_bitfield2format(pvt->chosenformat);
+			}
 		}
 		if (!voicefmt) {
-			/* Really shouldn't happen, but if it does, should be looked into */
-			ast_log(LOG_WARNING, "No voice format and no peer format available on %s, backlogging frame\n", ast_channel_name(pvt->owner));
+			/* This should never happen, since we should always be able to have an acceptable format to use. */
+			ast_log(LOG_ERROR, "No voice, peer, or chosen format available on %s, backlogging frame\n", ast_channel_name(pvt->owner));
 			goto cleanup; /* Don't crash if there's no voice format */
 		}
 		ret = jb_get(pvt->jb, &frame, ms, ast_format_get_default_ms(voicefmt));
@@ -11569,6 +11584,11 @@ static int socket_process_helper(struct iax2_thread *thread)
 											VERBOSE_PREFIX_4,
 											using_prefs);
 
+							/* Unlike unauthenticated calls, we don't need to store
+							 * the chosen format for channel creation.
+							 * However, this is helpful for __get_from_jb. */
+							iaxs[fr->callno]->chosenformat = format;
+
 							ast_set_flag(&iaxs[fr->callno]->state, IAX_STATE_STARTED);
 							c = ast_iax2_new(fr->callno, AST_STATE_RING, format,
 								&iaxs[fr->callno]->rprefs, NULL, NULL, 1);