Bug 257790

Summary:	HLS playback will not switch to high framerate variants on Safari
Product:	WebKit	Reporter:	Carl Lindqvist <carl.lindqvist>
Component:	Media	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED MOVED
Severity:	Normal	CC:	ahmad.saleem792, bfulgham, eric.carlson, jer.noble, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	Safari 16
Hardware:	Unspecified
OS:	Unspecified

Description Carl Lindqvist 2023-06-07 04:07:10 PDT

On desktop Safari, when playing an HLS presentation that has variants with both 25 and 50 fps, Safari will not switch to the higher framerate variants, but will stay on the 25fps stream. The expected result is that it should switch to the higher quality variants. This has been the case for some years now. I can't pinpoint the exact version where this started. Other players, including native playback on iOS and tvOS will switch up to the higher framerate variants without issue.

If the lower framerate variants are removed, Safari has no problem playing the 50fps streams and will play the top variant without issue.

Here is some sample content I have prepared. First, the full presentation. Safari will never go above the 2.5 megabit 25fps stream variant.
https://vod.streaming.a2d.tv/safari50/examplefull.ism/.m3u8

Here is the same content with the 25fps variants removed. This plays fine in Safari, and will switch to the HD variant.
https://vod.streaming.a2d.tv/safari50/example50only.ism/.m3u8

/Carl

Comment 1 Radar WebKit Bug Importer 2023-06-07 10:39:07 PDT

<rdar://problem/110406930>

Comment 2 Brent Fulgham 2023-08-04 17:08:57 PDT

This issue needs to be fixed outside of the Webkit Open Source project. Changing to RESOLVED | MOVED, with worked tracked by rdar://88207604.

We believe this is fixed in the current iOS 17 public betas.

Comment 3 Carl Lindqvist 2023-10-02 22:14:18 PDT

This was never an issue on mobile safari. How is the iOS fix related to desktop Safari? (I don't have access to see rdar tickets). The issue still exists in Safari 17.0 on desktop.

Comment 4 Eric Carlson 2023-10-04 14:16:04 PDT

Brent's "We believe this is fixed in the current iOS 17 public betas" comment is not correct, as you note this is only an issue on macOS. 

The team responsible for the macOS framework with the bug has identified the issue and is working on a fix.

Comment 5 Carl Lindqvist 2023-10-06 08:25:38 PDT

Thank you Eric, that is great news!