Chrome fires deviceReady event when cam is in use

Description

In Firefox 66 I get a deviceErrorCode name of “NotReadableError” if video is in use.

In Chrome 73 I do not get a deviceError in fact i get a deviceReady But when I try to start recording I get an error in console.

This data is captured in my local dev environment.

Steps to reproduce

On my Windows 10 (build 1803) development pc.

1. I start the local windows 10 camera app and let it hold camera.
2. I then proceed into my app and go to the video recording page.
3. In Chrome I get a deviceReady called in my page - my page enables the start video capture button.
4. When I click the start capture button get the above error in javascript console.

The error isn’t surprising, what is surprising is that I get a deviceReady. Despite reporting deviceReady I do not see the video preview it remains black.

Results

Expected

In Chrome I should receive deviceError event.

Actual

In Chrome I do receive a deviceReady event. It fails later in start() video capture.

Error output

This error appears in the Chrome js console when I execute start() because Chrome things I have the device due to deviceReady event.

VM16438 1.chunk.js:83096 VIDEOJS: ERROR: DOMException: Failed to execute 'start' on 'MediaRecorder': The MediaRecorder failed to start because there are no audio or video tracks available.
    at MediaStreamRecorder.record (http://localhost:5004/static/js/1.chunk.js:99218:21)
    at initRecorder (http://localhost:5004/static/js/1.chunk.js:97053:19)
    at Object.startRecording (http://localhost:5004/static/js/1.chunk.js:97035:5)
    at MRecordRTC.startRecording (http://localhost:5004/static/js/1.chunk.js:98180:28)
    at RecordRTCEngine.start (webpack://VideojsRecord/./src/js/engine/record-rtc.js?:96:19)
    at Record.startRecording (webpack://VideojsRecord/./src/js/videojs.record.js?:622:19)
    at Player.eval (webpack://VideojsRecord/./src/js/videojs.record.js?:600:22)
    at HTMLDivElement.bound (http://localhost:5004/static/js/1.chunk.js:116215:15)
    at HTMLDivElement.func (http://localhost:5004/static/js/1.chunk.js:116042:8)
    at HTMLDivElement.data.dispatcher (http://localhost:5004/static/js/1.chunk.js:115857:31)
    at trigger (http://localhost:5004/static/js/1.chunk.js:115995:25)
    at Player.trigger$$1 [as trigger] (http://localhost:5004/static/js/1.chunk.js:116904:12)
    at Player.(anonymous function) [as handleTechLoadedmetadata_] (http://localhost:5004/static/js/1.chunk.js:138060:17)
    at Html5.bound (http://localhost:5004/static/js/1.chunk.js:116215:15)
    at HTMLVideoElement.bound (http://localhost:5004/static/js/1.chunk.js:116215:15)

Additional Information

Please include any additional information necessary here. Including the following:

versions

videojs

“videojs-record”: “^3.6.0”

browsers

Launched in Incognito mode in Chrome to isolate addons.

OSes

Windows 10 build 1803 64bit, up to date patches.

[rluiten]

Nice, I should be able to figure where I am at with that page and your example. Thanks so much! I’ll let you know if I learn anything else I think might be useful.

[thijstriemstra]

this is from '15: https://stackoverflow.com/questions/31108855/webrtc-check-if-camera-and-microphone-are-in-use-on-chrome If it’s still a bug, chrome is just lame.

I do hope the chromium devs have an open issue for this, haven’t found it yet though.

The testrtc project has a test that detects silence from a microphone here that could be useful in determining if the audio track returned is silent, and a similar video test that detects frozen or black frames.

Come on, this can’t be real. 🤦‍♂️