laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bts/+/32128 )
Change subject: rtp continuous-streaming: fix BFI in the quality-suppressed case ......................................................................
rtp continuous-streaming: fix BFI in the quality-suppressed case
The check for (tch_ind->lqual_cb >= bts->min_qual_norm) in l1sap_tch_ind() has the intent of suppressing valid-seeming speech frame output from lower layers when the link quality is too low; this check is particularly important for FR1 codec where the intrinsic validity check is only a 3-bit CRC which has 1/8 probability of indicating "correct" when decoding radio noise during DTXu silence.
However, this check is effectively defeated in the current implementation of rtp continuous-streaming: the RTP packet being output is the presumed-bogus speech frame from lower layers, rather than the intended zero-length payload. Fix this bug.
Related: OS#5975 Change-Id: Icee0f57be289a0592a0197469432a012d15f224c --- M src/common/l1sap.c 1 file changed, 25 insertions(+), 2 deletions(-)
Approvals: laforge: Looks good to me, approved pespin: Looks good to me, but someone else must approve Jenkins Builder: Verified
diff --git a/src/common/l1sap.c b/src/common/l1sap.c index 89aea58..1f173db 100644 --- a/src/common/l1sap.c +++ b/src/common/l1sap.c @@ -1641,10 +1641,10 @@ return 1; } } else { - /* Are we in rtp continuous-stream special mode? If so, send + /* Are we in rtp continuous-streaming special mode? If so, send * out a BFI packet as zero-length RTP payload. */ if (bts->rtp_nogaps_mode) { - send_ul_rtp_packet(lchan, fn, msg->data, msg->len); + send_ul_rtp_packet(lchan, fn, NULL, 0); } else { DEBUGPGT(DRTP, &g_time, "Skipping RTP frame with lost payload (chan_nr=0x%02x)\n", chan_nr);