falconia has uploaded this change for review.
trau2rtp HR: update to TW-TS-002 version 1.2.0
osmo_trau2rtp() in HRv1 mode emits either RFC 5993 or TW-TS-002
format, depending on whether or not the latter extended format is
enabled. TW-TS-002 can represent BFIs and invalid SID frames,
in addition to good speech and valid SID in common with RFC 5993.
TW-TS-002 spec has recently been updated to version 1.2.0:
https://www.freecalypso.org/specs/tw-ts-002-v010200.txt
The principal difference is the way invalid SID frames are
represented: in version 1.1.0 all payload bits were stripped
in the case of invalid SID; version 1.2.0 allows these payload
bits to be preserved if they exist. Section 5.4 in the new spec
version provides the detailed rationale for this change.
Change osmo_trau2rtp() operating on HR frames in TW-TS-002 mode
to emit invalid SID frames in the "verbose" form of TW-TS-002
version 1.2.0.
Compatibility considerations: there is no currently released or
deployed software that accepts TW-TS-002 version 1.1.0 but not
version 1.2.0. More specifically:
* osmo_rtp2trau() in TRAU-UL/TFO output mode accepts invalid SID
in both short and long forms since first implementation;
* Themyscira libgsmhr1, the library that accepts TW-TS-002 RTP input
for either full speech decoding or TFO transform, has not yet
reached its first release. The current code in Hg implements
TW-TS-002 version 1.2.0, thus the library will support both short
and long forms of invalid SID upon its upcoming first release.
Change-Id: I497ad7b1f0f7229dc9a50cd3cc318e3dc1394171
---
M src/trau/trau_rtp_conv.c
M tests/trau_conv/trau2rtp_hr_twts002.ok
2 files changed, 7 insertions(+), 5 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmo-abis refs/changes/99/39799/1
diff --git a/src/trau/trau_rtp_conv.c b/src/trau/trau_rtp_conv.c
index a36d317..f2e0022 100644
--- a/src/trau/trau_rtp_conv.c
+++ b/src/trau/trau_rtp_conv.c
@@ -294,9 +294,10 @@
if (tf->c_bits[11] && sidc == OSMO_GSM631_SID_CLASS_SPEECH)
out[0] = FT_BFI_WITH_DATA << 4;
twts002_hr16_set_extra_flags(out, tf);
- /* invalid SID frames are truncated in TW-TS-002 */
+ /* Invalid SID handling updated in TW-TS-002 version 1.2.0:
+ * see sections 5.4 and 6.2.3. */
if (sidc == OSMO_GSM631_SID_CLASS_INVALID)
- return 1;
+ out[0] |= 0x04; /* Invalid_SID_Verbose bit */
}
/* TS 101 318 Section 5.2: The order of occurrence of the codec parameters in the buffer is
@@ -398,12 +399,13 @@
/* can be represented only in TW-TS-002, not in RFC 5993 */
if (!emit_twts002)
return 0;
- out[0] = FT_INVALID_SID << 4;
+ out[0] = (FT_INVALID_SID << 4) | 0x04; /* Invalid_SID_Verbose */
twts002_hr8_set_extra_flags(out, tf);
/* XC4 is TAF with this frame type */
if (tf->xc_bits[3])
out[0] |= 0x01;
- return 1; /* short format per TW-TS-002 */
+ osmo_ubit2pbit(out + 1, tf->d_bits, 112);
+ return GSM_HR_BYTES_RTP_RFC5993;
case 6:
case 7:
/* bad speech frame (BFI=1, SID=0) */
diff --git a/tests/trau_conv/trau2rtp_hr_twts002.ok b/tests/trau_conv/trau2rtp_hr_twts002.ok
index db65082..3593eb9 100644
--- a/tests/trau_conv/trau2rtp_hr_twts002.ok
+++ b/tests/trau_conv/trau2rtp_hr_twts002.ok
@@ -7,7 +7,7 @@
00C4FF2305E137DF28F928DD5231EB
00CCFF0580FEB85D20AF485C70CFD0
20025FBB32FFFFFFFFFFFFFFFFFFFF
-10
+140399BCE3FFFFFFFFFFFFDD7FFAFF
70
70
70
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