Document the Audio and Video flow
test result of invoking audioTrack.getMediaStreamTrack().getSettings() and audioTrack.getMediaStreamTrack().getConstraints():
For Chrome:
- passed customized microphoneDeviceId, echoCancellation, bitrate and sampleRate to create microphone track, but in result of
audioTrack.getMediaStreamTrack().getSettings(), only device id is set correctly. echoCancellation result is always true, no bitrate in result, sampleRate is higher then what I pass.
The result of audioTrack.getMediaStreamTrack().getConstraints() just contains correct deviceId and sampleRate.
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After apply constraints manually. getSettings result doesn't change, getConstraints result does not change directly, but after several seconds, getConstraints changes.
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When I wait for more seconds, getSettings result still doesn't change any more.
For Firefox:
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Create microphone track situation: in both getSettings and getConstraints result, sampleRate and bitrate info are hidden, deviceId is right. But echoCancellation is always true in getSettings, meanwhile it's hidden in getConstraints
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Apply constraints situation: getSettings result keeps same, getConstraints result can not see echoCancellation directly, but after several seconds, it changes.
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When I wait for more seconds, echoCancellation in getSettings finally changes. Both autoGainControl and noiseSuppression changes to false with it.
conclusion: We can check current browser supported constraint list via navigator.mediaDevices.getSupportedConstraints(), for constraints that are not in the list, it doesn't work if we pass to browser.
