A rework of WebKitMediaSrc introducing many stability and code maintainance improvements was introduced in https://bugs.webkit.org/show_bug.cgi?id=199719, but later reverted due to bugs in the track handling of playbin3, which it depended upon. It is planned to reintroduce it in a way that doesn't hit these bugs. No patch at the moment. This bug has just been created so that other bugs can be marked as "depend on" it.
*** Bug 211910 has been marked as a duplicate of this bug. ***
*** This bug has been marked as a duplicate of bug 225192 ***