Sps/pps not being passed by atomcams h264 1080p stream, causes SDP video fmtp to not be populated

[baudneo]

I have started 2 issues about this on this repo and 1 more on atomcams and v4lrtspserver each.

The answer I got from the v4lrtspserver maintainer is that the video stream for 1080p is not passing SPS/PPS. This causes the main 1080p stream to not have a profile-level-id.

This in turn causes janus webrtc gateway to error out. As it requires a profile-level-id to parse codec requirements.

VLC and other rtsp players can parse the stream without an explicit profile-level-id. I do not know if it is strictly required but for the case of janus webrtc gateway, it is.

The v4lrtspserver maintainer has asked me to look into v4lrtspserver debug logs but I can't seem to locate where v4lrtspserver command is called from to edit the arguments.

Can anyone point me towards where that is?

Example of mainstream RTSP DESCRIBE response

CSeq: 1
Date: Sun, Aug 07 2022 03:44:20 GMT
WWW-Authenticate: Digest realm="LIVE555 Streaming Media", nonce="2431aaa7fb9fa620e8665597fd90b059"

RTSP/1.0 200 OK
CSeq: 2
Date: Sun, Aug 07 2022 03:44:20 GMT
Content-Base: rtsp://10.0.1.67:8554/video1_unicast/
Content-Type: application/sdp
Content-Length: 563

v=0
o=- 1659831422316587 1 IN IP4 10.0.1.67
s=LIVE555 Streaming Media v2022.04.26
i=LIVE555 Streaming Media v2022.04.26
t=0 0
a=tool:LIVE555 Streaming Media v2022.04.26
a=type:broadcast
a=control:*
a=range:npt=now-
a=x-qt-text-nam:LIVE555 Streaming Media v2022.04.26
a=x-qt-text-inf:LIVE555 Streaming Media v2022.04.26
m=video 0 RTP/AVP 96
c=IN IP4 0.0.0.0
b=AS:500
a=rtpmap:96 H264/90000
a=fmtp:96
a=x-dimensions:1920,1080
a=control:track1
m=audio 0 RTP/AVP 97
c=IN IP4 0.0.0.0
b=AS:500
a=rtpmap:97 L16/16000
a=fmtp:97
a=control:track2

[janus-ZM] [Sat Aug  6 21:44:22 2022] [ERR] [plugins/janus_streaming.c:janus_streaming_rtsp_parse_sdp:6349] [2] cannot parse video fmtp...
[janus-ZM] [Sat Aug  6 21:44:22 2022] [ERR] [plugins/janus_streaming.c:janus_streaming_process_synchronous_request:3254] Error creating 'rtsp' stream...

The part that causes the error is on the video media definitions

m=video 0 RTP/AVP 96
c=IN IP4 0.0.0.0
b=AS:500
a=rtpmap:96 H264/90000
a=fmtp:96
a=x-dimensions:1920,1080
a=control:track1

That is the whole video media block, the a=fmtp:96is the line where profile-level-id sprop, and packetization attributes should be.

The substream is parsed correctly and has the needed attributes but the 1080p mainstream does not. This is technically a broken rtsp implementation according to the janus webrtc gateway maintainers.

[baudneo]

Found the v4lrtspserver init script -> https://github.com/gtxaspec/wz_mini_hacks/blob/master/SD_ROOT/wz_mini/etc/network.d/S15v4l2rtspserver