Webcam not working w/ Chrome

[AlfaGTA]

Hi all, first post here - please help!

Briefly: webcam does not work with Chrome, does work with Firefox. (OpenBSD 7.1 -current #427 amd64.)

I have done all the usual things to get A/V working on OpenBSD:
- set kern.audio/video.record
- enable wasm for chrome
- chown /dev/video

When I try Jitsi/Zoom with Chrome, the webcam lights up for a fraction of a second then dark again.

Any ideas please?

[jggimi]

Hello and welcome!

Two quick things to check -- though I do need caffeine after a long work day, so this might be less than useful

• Check audio device ownership status
• Start the browser in a terminal window so you can capture stdout / stderr messages, which might point to a root cause for the failure.

[AlfaGTA]

Thanks

Originally Posted by jggimi

• Check audio device ownership status
• Start the browser in a terminal window so you can capture stdout / stderr messages, which might point to a root cause for the failure.

- audio works fine in zoom
- video receive is OK in zoom
- webcam works fine with /usr/X11R6/bin/video

Thanks for your help!

Error log:
[29181:-1146955712:0322/112000.584602:ERROR:mdns_responder.cc(889)] mDNS responder manager failed to start.
[29181:-1146955712:0322/112000.584717:ERROR:mdns_responder.cc(907)] The mDNS responder manager is not started yet.
[46719:1691999808:0322/112001.572698:ERROR:webrtc_video_engine.cc(3481)] Absent receive stream; ignoring clearing encoded frame sink for ssrc 0
[46719:1691999808:0322/112013.965203:ERROR:webrtc_video_engine.cc(3481)] Absent receive stream; ignoring clearing encoded frame sink for ssrc 0
[46719:-1946173376:0322/112016.679629:ERROR:dtls_transport.cc(120)] DtlsTransport in connected state has incomplete TLS information
[46719:-1946173376:0322/112016.680069:ERROR:dtls_srtp_transport.cc(214)] No DTLS-SRTP selected crypto suite
[46719:-1946173376:0322/112016.986001:ERROR:dtls_transport.cc(120)] DtlsTransport in connected state has incomplete TLS information
[46719:-1946173376:0322/112016.986117:ERROR:dtls_srtp_transport.cc(214)] No DTLS-SRTP selected crypto suite
[46719:-1946173376:0322/112022.139459:ERROR:stun_port.cc(288)] Port[c4e91000:0:1:0:local:Net[msk0:192.168.1.x/24:Ethernet:id=1]]: UDP send of 998 bytes to host 192.168.1.x:28396 (192.168.1.x:28396) failed with error 35
[46719:-1946173376:0322/112022.139698:ERROR:stun_port.cc(288)] Port[c4e91000:0:1:0:local:Net[msk0:192.168.1.x/24:Ethernet:id=1]]: UDP send of 998 bytes to host 192.168.1.x:28396 (192.168.1.x:28396) failed with error 35
[46719:-1946173376:0322/112022.139850:ERROR:stun_port.cc(288)] Port[c4e91000:0:1:0:local:Net[msk0:192.168.1.x/24:Ethernet:id=1]]: UDP send of 998 bytes to host 192.168.1.x:28396 (192.168.1.x:28396) failed with error 35
[46719:-1946173376:0322/112022.139999:ERROR:stun_port.cc(288)] Port[c4e91000:0:1:0:local:Net[msk0:192.168.1.x/24:Ethernet:id=1]]: UDP send of 998 bytes to host 192.168.1.x:28396 (192.168.1.x:28396) failed with error 35
[46719:-1946173376:0322/112022.140148:ERROR:stun_port.cc(288)] Port[c4e91000:0:1:0:local:Net[msk0:192.168.1.x/24:Ethernet:id=1]]: UDP send of 998 bytes to host 192.168.1.x:28396 (192.168.1.x:28396) failed with error 35

[jggimi]

I don't have a webcam and can't replicate anything -- so these are just my thoughts regarding your log:

• I wouldn't worry about the mDNS messages; I interpret this to indicate you don't have mDNS configured on your local network. https://en.wikipedia.org/wiki/Multicast_DNS
• I'm not sure if the WebRTC messages are normal; a brief internet search doesn't point to much about "Absent receive stream; ignoring clearing encoded frame sink" messages, and I don't have an understanding of the source code module that produces them. https://chromium.googlesource.com/ex...ideo_engine.cc
• The UDP traffic results in error 35, which if errno(2) is used for these numbers would be EAGAIN, classified as a temporary error.

[AlfaGTA]

OK, thanks! Looks like I need to investigate the WebRTC message...

[jggimi]

Yeah, except that the temporary errors are ALSO produced by WebRTC: https://chromium.googlesource.com/ex...e/stun_port.cc

[AlfaGTA]

Btw, in my /etc/rc.conf.local I have

multicast=YES
pkg_scripts=messagebus avahi_daemon gdm

[jggimi]

That looks right, as messagebus is started before avahi. I don't use avahi, but perhaps your PF configuration is blocking either mDNS or SSDP?

(I'm pretty certain that this particular provision isn't related to your WebRTC issue. )

[AlfaGTA]

Indeed disabling PF in /etc/rc.conf I get the same errors ...

[jggimi]

Let's look at the source code that produced that warning, mdns_responder.cc:

  size_t num_started_socket_handlers = socket_handler_by_id_.size();
  if (socket_handler_by_id_.empty()) {
    start_result_ = SocketHandlerStartResult::ALL_FAILURE;
    throttled_start_end_ = tick_clock_->NowTicks() + kManagerStartThrottleDelay;
    LOG(ERROR) << "mDNS responder manager failed to start.";
    ReportServiceError(MdnsResponderServiceError::kFailToStartManager);
    return;
  }

This is a local network socket issue that produces the message.

I've started avahi_daemon, and started chrome from within an xterm, and I don't see any stdout or stderr messages at all, so I can't reproduce this particular message.

If this issue is related to unveil(2) mitigations, you could disable it to see if you get different results, per /usr/local/share/doc/pkg-readmes/chromium.

[AlfaGTA]

Thanks, but it seems to be chromium's fault. I have just installed OpenBSD -current on another laptop and the webcam works fine with chromium (audio doesn't ). Also, I get the same mDNS errors.

To reproduce the errors try https://zoom.us/test
When using jitsi I don't get any error

[jggimi]

Unfortunately, I don't have a webcam so cannot recreate the problem. (And I have xdg-open attempting to use firefox with a test userid even when the default browser and url scheme settings point to chrome.)

[AlfaGTA]

No worries, and thanks for your help. This looks like an unsolved Chromium bug:

https://bugs.chromium.org/p/chromium...tail?id=470717

[AlfaGTA]

Originally Posted by jggimi

If this issue is related to unveil(2) mitigations, you could disable it to see if you get different results, per /usr/local/share/doc/pkg-readmes/chromium.

Thanks for the suggestion. Disabling unveil does not change the error messages.

[jggimi]

You might post about this problem to a wider audience. I recommend you consider an informal problem report to the ports@ mailing list. If you post, be sure to include a full dmesg(8) that includes the webcam.

[AlfaGTA]

Sure, I will do that.

To conclude the thread, with Firefox instead
- jitsi works fine
- zoom gets a/v connected, although video is pretty much unuseable (and had to spoof useragent to get it working)