## Audio on FPV (Experimental) ### Overview Everything has been tested using steamdeck (PC x86) and ssc338q-imx415 Anjoy board and choice of decoders and similar may reflect this. Cúrrently there is ~200msec delay on audio stream, encoding settings may improve this (smaller packets, opus supports 20msec intervals), changing OS settings, changing to PCM/PCMA/PCMU. Most interesting observation is that the audio/video is perfectly synced in recorded TS file. It indicates delay comes from the decoder chain in GSTreamer. If using mpegtsmux like I did, there is no need for decoding and parsing when using OPUS. ### Majestic and general settings Audio settings (majestic.yaml): ``` cli -s .audio.enabled true cli -s .audio.srate 8000 (goes up to 48000 but consumes more bandwidth) ``` Port can be set (default 5700) with: `cli -s .outgoing.audioPort 6200` (does it really work?) ### Quick wfb_ng setup Example wfb_ng setup: Drone: ``` wfb_tx -p -u 5700 -K /etc/drone.key -k 8 -n 12 -i 7669207 -f data wlan0 ``` GS: ``` wfb_rx -p 0 -c 127.0.0.1 -u 5700 -K /etc/gs.key -i 7669207 wlan1 ``` ### Client side audio & video commands GST command for opus 8000hz (sound only): ``` gst-launch-1.0 udpsrc port=5700 ! application/x-rtp, payload=98, encoding-name=OPUS ! rtpopusdepay ! opusdec ! audioconvert ! autoaudiosink sync=false ``` ### Working sound, video & save!!!! ``` gst-launch-1.0 udpsrc port=5600 caps='application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H265' ! rtpjitterbuffer ! rtph265depay ! tee name=videoTee ! queue ! ts. udpsrc port=5700 ! application/x-rtp, payload=98, encoding-name=OPUS ! rtpjitterbuffer ! rtpopusdepay ! tee name=audioTee ! queue ! ts. mpegtsmux name=ts ! filesink location=/run/media/deck/170a3e7f-325f-4567-8580-0e01dda76973/video/record-$(date +%y%m%d_%H%M%S).tsn sync=true -e videoTee. ! vaapih265dec ! fpsdisplaysink fps-update-interval=250 video-sink=autovideosink text-overlay=true sync=false audioTee. ! opusdec ! audioconvert ! pulsesink sync=false ``` ### Video & sound play ``` gst-launch-1.0 udpsrc port=5600 caps='application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H265' ! rtph265depay ! vaapih265dec ! autovideosink sync=false udpsrc port=5700 ! application/x-rtp, payload=98, encoding-name=OPUS ! rtpopusdepay ! opusdec ! audioconvert ! autoaudiosink sync=false ``` ### Video & sound record ``` gst-launch-1.0 udpsrc port=5600 caps='application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H265' ! rtpjitterbuffer ! rtph265depay ! queue ! ts. udpsrc port=5700 ! application/x-rtp, payload=98, encoding-name=OPUS ! rtpjitterbuffer ! rtpopusdepay ! queue ! ts. mpegtsmux name=ts ! filesink location=/run/media/deck/170a3e7f-325f-4567-8580-0e01dda76973/video/record-$(date +%y%m%d_%H%M%S).tsn sync=true -e ``` ### FFPLAY command for opusn 8000hz (sound only): ``` ffplay.exe -fflags nobuffer -vn -flags low_delay -strict experimental -deadline realtime -framedrop -protocol_whitelist file,crypto,rtp,tcp,udp opus_audio.txt opus_audio.txt (sdp) v=0 o=StreamingServer 38990265062388 38990265062388 IN IP4 0.0.0.0 s=RTSP Session c=IN IP4 0.0.0.0 t=0 0 a=range:npt=0- m=video 5600 RTP/AVP 97 a=control:video a=rtpmap:97 H265/90000 a=fmtp:97 profile-level-id=016000; packetization-mode=1; a=framerate:90 m=audio 5700 RTP/AVP 98 a=control:audio a=rtpmap:98 opus/8000/1 ``` ### TODO & suggestions: Optimize and adapt GST commands to different gs platforms. ### /etc/wfb.conf add audio specific parameters like port, fec, ... ### /usr/bin/wifibroadcast add "if audio_enabled=true in datalink.conf then start wfb_tx ....."