Merge pull request #1 from josephnef/feat/multistream-tx

Multi-stream wfb_tx: per-stream FEC profiles, priority drain, waybeam SHM input (one process for all streams)

Author: josephnef

Changelog.md

@@ -1,3 +1,23 @@
+fork: multi-stream wfb_tx (feat/multistream-tx)
+-----------------------------------------------
+ - One `wfb_tx` process can now serve several streams via repeatable `-y` specs
+   (`u=<udp_port>|shm=<ring>,p=<radio_port>[,k=][,n=][,T=][,F=][,mcs=][,bw=][,gi=][,stbc=][,ldpc=][,vht=][,nss=]`).
+   Each stream gets its own FEC encoder, session key and radiotap header on the shared
+   link_id, exactly as N separate processes would - but in one event loop. Without `-y`
+   nothing changes.
+ - Spec order is strict drain priority (first = highest): under radio saturation the
+   socket buffers of later streams overflow first. Intended for layered video (e.g.
+   SVC-T from OpenIPC waybeam_venc): the always-decodable base layer is stream 0 with
+   strong FEC, droppable enhancement layers ride behind it with light FEC.
+ - `shm=<ring_name>` stream input: attach to an OpenIPC waybeam_venc shared-memory
+   packet ring (`/dev/shm/<ring_name>`, vendored `src/venc_ring.{h,c}`, MIT) for a
+   syscall-free producer path. Survives producer respawn via epoch-based re-attach.
+ - Per-stream runtime control: `wfb_tx_cmd <port> {set,get}_{fec,radio}_stream -r <radio_port> ...`
+   (new control-port commands CMD_*_STREAM; legacy commands keep addressing the first
+   stream). Unknown radio_port answers ENODEV.
+ - Per-stream stdout stats: `PKT_S` / `TX_ANT_S` lines tagged with the radio_port, plus
+   the legacy aggregate `PKT` / `TX_ANT` lines so existing stats parsers keep working.
+
 23.08 upcoming release
 ----------------------
  - Mavlink parser speedup. Instead of using standard full-featured (and slow mavlink parser) now use fast packet splitter.

Makefile

@@ -51,8 +51,8 @@ src/%.o: src/%.cpp src/*.hpp src/*.h
 wfb_rx: src/rx.o src/radiotap.o src/zfex.o src/wifibroadcast.o
 	$(CXX) -o $@ $^ $(_LDFLAGS) -lpcap
 
-wfb_tx: src/tx.o src/zfex.o src/wifibroadcast.o
-	$(CXX) -o $@ $^ $(_LDFLAGS)
+wfb_tx: src/tx.o src/zfex.o src/wifibroadcast.o src/venc_ring.o
+	$(CXX) -o $@ $^ $(_LDFLAGS) -pthread
 
 fec_test: src/fec_test.cpp src/zfex.o
 	$(CXX) $(_CFLAGS) -o $@ $^ $(LDFLAGS) $(shell pkg-config --libs catch2-with-main)

README.md

@@ -180,6 +180,50 @@ Camera --[RTP stream (UDP)]--> wfb_ng --//--[ RADIO ]--//--> wfb_ng --[RTP strea
                 ! rtph264depay ! avdec_h264 ! clockoverlay valignment=bottom ! autovideosink fps-update-interval=1000 sync=false
  ```
 
+## Multi-stream wfb_tx (fork feature: per-stream FEC profiles in one process)
+
+One `wfb_tx` can serve several streams, each with its own radio_port, FEC profile,
+session key and radiotap header — designed for unequal error protection of layered
+video (SVC-T from [OpenIPC waybeam_venc](https://github.com/OpenIPC/waybeam_venc)):
+the always-decodable base layer rides strong FEC, the droppable enhancement layer
+rides light FEC, and one process replaces N.
+
+```
+wfb_tx -K drone.key -i 7669206 -C 7003 \
+       -y "u=5600,p=0,k=8,n=12,T=15" \      # base video    (priority 0 = drained first)
+       -y "u=5605,p=1,k=8,n=9,T=15" \       # enhance video (sheds load first when saturated)
+       wlan0
+```
+
+Stream spec keys: `u=<udp_port>` or `shm=<waybeam venc_ring name>` (input, exactly one),
+`p=<radio_port>` (required, unique), `k`/`n`/`T`/`F` (FEC), `mcs`/`bw`/`gi`/`stbc`/`ldpc`/`vht`/`nss`
+(per-stream radiotap). Unset keys inherit the global options. Spec order is strict drain
+priority: ready inputs are serviced first-spec-first and drained fully, so under radio
+saturation the kernel socket buffers of later streams overflow first — by design. Note
+that a continuously saturating higher-priority stream can starve lower ones; order
+streams by importance (base > audio > enhance > telemetry).
+
+`shm=<name>` attaches to a waybeam_venc shared-memory packet ring (`/dev/shm/<name>`,
+one complete RTP packet per slot — set waybeam's `outgoing.server` to `shm://<name>`
+and `outgoing.enhancePort` to get a second `<name>_enh` ring). The reader survives
+producer respawns (epoch-based re-attach). With debug mode (`-D port`), stream *i*
+emulates its wlans on ports `port + i*num_wlans + wlan_idx`.
+
+Runtime per-stream control (e.g. closed-loop FEC adaptation of the enhancement layer):
+
+```
+wfb_tx_cmd 7003 get_fec_stream -r 1
+wfb_tx_cmd 7003 set_fec_stream -r 1 -k 8 -n 10
+wfb_tx_cmd 7003 set_radio_stream -r 1 -M 2
+```
+
+On the ground side run one `wfb_rx` per stream as usual (`-p 0`, `-p 1`, ...). For
+SVC-T both decoded outputs can feed the same decoder port — the streams share one
+RTP sequence space (see waybeam_venc `outgoing.enhancePort`). Stats: multi-stream
+mode emits per-stream `PKT_S`/`TX_ANT_S` stdout lines tagged with the radio_port in
+addition to the legacy aggregate `PKT`/`TX_ANT` lines, which existing parsers keep
+understanding unchanged. Without any `-y` option wfb_tx behaves exactly as upstream.
+
 ## HOWTO build:
 
 For development (inline build)