Attention is currently required from: falconia.
Hello Jenkins Builder,
I'd like you to reexamine a change. Please visit
https://gerrit.osmocom.org/c/osmo-bts/+/32099
to look at the new patch set (#3).
Change subject: rtp continuous-streaming: add themyscira-bfi option
......................................................................
rtp continuous-streaming: add themyscira-bfi option
The just-added rtp continuous-streaming mode solves the principal
problem of OS#5975, but there is still room for improvement,
particularly in the case of FR and EFR codecs. The BFI packet
format sent in our rtp continuous-streaming mode (without additional
qualifiers) is zero-length RTP payload, which has the benefit of
being universal, applicable to any codec type and any encoding
variant. However, this most generic BFI packet format lacks the
ability to represent the Time Alignment Flag (TAF) of GSM 06.31
and 06.81, traditionally carried in TRAU UL frames of GSM 08.60
in the classic GSM RAN architecture.
There exist published-source implementations of FR and EFR decoders
that implement Rx DTX handler functions exactly to the letter of
GSM 06.31 and 06.81 specs, they take BFI and TAF flags as inputs
along with received frame payloads, and they rely on the TAF bit
being correct (reflecting the frame position relative to SACCH)
when BFI=1. A need is thus created for an RTP transport mechanism
for FR&EFR that includes BFI marker packets that contain this TAF bit.
An ad hoc extension to the standard RTP transport format for FR&EFR
that does exactly what has just been described has been implemented
by Themyscira Wireless, a retronetworking intentional community (RNIC)
that operates an Osmocom-based GSM network. The present change adds
OsmoBTS support for this Themyscira RTP BFI extension, and it does so
by extending the rtp continuous-streaming vty option added just
previously; the new option becomes:
rtp continuous-streaming [themyscira-bfi]
If the last qualifier is included, the special Themyscira extension
mode is enabled. In this mode, which only affects FR and EFR codecs,
RTP packets emitted when there is no speech or SID frame to be sent
change from zero-length RTP payload to Themyscira BFI marker format,
including TAF.
Related: OS#5975
Change-Id: Ib935efb1f7c9c8d919a4a0ea2bef244a47e5fb24
---
M include/osmo-bts/bts.h
M src/common/l1sap.c
M src/common/vty.c
M src/osmo-bts-trx/sched_lchan_tchf.c
M tests/osmo-bts.vty
5 files changed, 96 insertions(+), 13 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/99/32099/3
--
To view, visit https://gerrit.osmocom.org/c/osmo-bts/+/32099
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: Ib935efb1f7c9c8d919a4a0ea2bef244a47e5fb24
Gerrit-Change-Number: 32099
Gerrit-PatchSet: 3
Gerrit-Owner: falconia <fal...@freecalypso.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Attention: falconia <fal...@freecalypso.org>
Gerrit-MessageType: newpatchset
