image.decode() promise does not resolve nor reject on some resources. Valid <img src=mp4> with hvc1 encoded payloads no longer resolve or reject in latest macOS, iOS betas and Tech Preview (regression). This might be related to bug 216088. Additionally, <img src=mp4> with av1 byte streams also do not resolve nor reject but this is pre-existing in all versions of Safari.


const img = new Image();
img.src = "hvc1.mp4";
document.body.appendChild(img);

// will not return
await img.decode();

You can see this tested here: https://colinbendell.github.io/webperf/img-decode-promise/

(NB: the above wpt test may yield some false-negatives due to github latencies and the aggressive timeouts)