Safari ignores the codecs parameter when evaluating contenttype in picture and video source tags. https://colinbendell.github.io/webperf/video-source-type-codecs/index2.html <video muted autoplay inline> <source src="Ottawa_River-invalid.webm" type="video/webm;codecs=invalid"> <source src="Ottawa_River-invalid.mp4" type="video/mp4;codecs=invalid"> <source src="Ottawa_River-h264.mp4" type="video/mp4;codecs=avc1"> </video> Safari picks the first mp4 while chrome currently only selects the avc1 entry. Firefox rejects all of them.
<rdar://problem/35445600>