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Chrome coalesces getUserMedia calls for one device onto a shared device session. Every spec boundary in this file stops all tracks, dropping the session's consumer count to zero and starting an asynchronous teardown in the audio service; the next spec's getUserMedia is then occasionally told the device is already open and joins the dying session, failing with NotReadableError: Could not start audio source. Which spec fails depends on where the race lands, so it presents as an intermittent failure scattered across the interop tests, more frequent on loaded machines. A single audio track acquired for the file's whole run keeps the consumer count above zero, so no teardown ever races a join. Ten consecutive runs in an environment reproducing the failure on roughly two in five runs came back clean.
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The Web SessionDescriptionHandler interop specs fail intermittently with
NotReadableError: Could not start audio source, landing on a different spec each time and more often on loaded machines.Chrome coalesces
getUserMediacalls for one device onto a shared device session. Every spec boundary in this file stops all tracks, dropping the session's consumer count to zero and starting an asynchronous teardown in the audio service. The next spec'sgetUserMediais then occasionally told the device is already open and joins the dying session; the track start lands inside the teardown and fails. Chrome's verbose log shows the close and the failure on the same session id, 1.4ms apart.A single audio track acquired in
beforeAlland released inafterAllkeeps the consumer count above zero for the file's whole run, so no teardown ever races a join. Ten consecutive runs in an environment reproducing the failure on roughly two runs in five came back clean; on this branch the suite shows only the three failures #2 fixes, with the intermittent one gone.Proposed upstream
The race is upstream's, present on pristine 0.21.2 at the same rate, so the same change is proposed to onsip/SIP.js as onsip#1128. The fork ships it without waiting on that review; if upstream lands it first, this becomes a cherry-pick.