Safari is able to play Dolby Vision Profile 5 (dvh1.05.04) and Profile 8 (dvh1.08.07) videos. However Safari incorrectly reports that it does not support Dolby Vision Profile 8 in several APIs, including HTMLMediaElement.canPlayType, MediaSource.isTypeSupported and navigator.mediaCapabilities. For example, in Safari 17, MediaSource.isTypeSupported('video/mp4;codecs="dvh1.05.04"') returns true, which is expected. But MediaSource.isTypeSupported('video/mp4;codecs="dvh1.08.07"') returns false, which is not expected. A test case webpage can be found here: http://ott.dolby.com/codec_test/index.html where Safari shows correct supporting status in Dolby Vision Profile 5, it shows false and not supported in Dolby Vision Profile 8 although Safari actually is able to play it. This bug affects some websites that use these APIs to try to detect the browser's capability of playing Dolby Vision videos, such as https://www.bilibili.com/video/BV1QX4y1i7B1/, where due to the bug mentioned above, the web page thinks that Safari does not support Dolby Vision Profile 8 video and hides the option for Dolby Vision.
<rdar://problem/116601656>
I can confirm that this is a new bug in Safari 17 on Sonoma. Safari 16 on Ventura does not have this bug.
Created attachment 468337 [details] Safari 17 incorrectly shows that it does not support Dolby Vision Profile 8
Created attachment 468338 [details] Safari 16 correctly shows that it supports Dolby Vision Profile 8
The fix for this issue needs to be made outside of the WebKit Open Source project. Resolving as MOVED.