Bug 180863 - HLS WebGL video textures, UNPACK_FLIP_Y_WEBGL breaks rendering with Safari 11 macOS 10.12.6
Summary: HLS WebGL video textures, UNPACK_FLIP_Y_WEBGL breaks rendering with Safari 11...
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebGL (show other bugs)
Version: Safari 11
Hardware: Mac macOS 10.12
: P2 Normal
Assignee: Nobody
Keywords: InRadar
Depends on:
Reported: 2017-12-15 04:28 PST by Daniel Rossi
Modified: 2021-03-18 04:34 PDT (History)
7 users (show)

See Also:


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Description Daniel Rossi 2017-12-15 04:28:40 PST
I am confirming that UNPACK_FLIP_Y_WEBGL is still breaking HLS rendering with Safari 11 on macOS 10.12.6. I have reported these issues before but no resolution. I have seperated this out with bugs in IOS 11 which flipy now has no effect at all. 

The Flipy flags cause black rendering like the IOS 11 HLS problem. No flag change fixes it apart from disabling FlipY. 

It has to be worked around by disabling Flipy and inverting the y coordinate on the vertex shader. 

With Flipy Flags:


Without FlipY flags and using shader Y inverse. Works.  


Mp4 with FlipY is fine


Please see these tickets for reference

Comment 1 Radar WebKit Bug Importer 2017-12-18 01:16:14 PST
Comment 2 Daniel Rossi 2017-12-19 02:11:09 PST
I've had to go back to my original ticket and findings. Someone is complaining that Safari 10 and Yosemite has the same problem as IOS 11 with HLS. As in the flipY fix does nothing. 

Just another problem to look out for and enable canvas rendering for instead as a work around.
Comment 3 Daniel Rossi 2017-12-24 17:44:29 PST
I'm sorry but I just stumbled across a comment in regards to macOS 10.13. Is this out yet ? 

So I will have to create yet another platform version check to not use flipY work arounds for 10.13 ! 

I am using a cloud based macOS as I don't have hardware and vmware was very complicated to maintain and hacky. It is difficult to keep things up to date in that automatically. Is 10.13 out yet ? 


A flipY for textures says is  fixed but this was never an issue with mp4 ? Was it tested with HLS textures ? 

Comment 4 Daniel Rossi 2017-12-26 03:50:48 PST
I now have reports from someone on High Sierra 10.13 the FlipY work around which I am reporting here is totally broken. Just like going from IOS 10 to IOs 11 the FlipY work around stopped working and there is a complete breakage. And it seemed just after that FlipY "fix" which was never a problem with Mp4 to begin with totally broke in HLS which I believe HLS wasn't even tested. 

Shall we forget about 10.12, people will have to do the countless platform checks and provide the workarounds for backwards compatibility. 

I believe we have to roll this issue back with the IOS 11 ticket.
Comment 5 Daniel Rossi 2017-12-26 03:52:00 PST
I believe this "fix" created a "regression" or something. 

Comment 6 Daniel Rossi 2017-12-26 08:33:13 PST
Scratch that. I can't edit my comments. They now say the flipy work around is ok.  

This problem is still relevant to 10.13 then. Requires FlipY disabled.
Comment 7 Justin Fan 2018-04-11 12:39:04 PDT
(In reply to Daniel Rossi from comment #6)
> Scratch that. I can't edit my comments. They now say the flipy work around
> is ok.  
> This problem is still relevant to 10.13 then. Requires FlipY disabled.

Hi Daniel, I cannot replicate the black screen issue on Safari Tech Preview on 10.13.14, but I noticed that you have both FLIP_Y set to true and the shader workaround enabled on your webgl-hls.html example. Can you confirm your experience on the latest Safari Tech Preview?
Comment 8 Kimmo Kinnunen 2021-03-18 03:15:13 PDT
As per Justin's comments, I'm closing this one out as already working.
I cannot access the test cases anymore.
If there is problems around this area, please file a new bug, thanks!
Comment 9 Daniel Rossi 2021-03-18 04:34:15 PDT
This is very old. I implemented the shader work arounds. Which I've now removed now it's not needed. IOS update corrected itself in IOS 11.1.  But HLS is broken again in IOS 14.4 on Iphone only. There is another ticket for that. HLS rendering on Ipad is fine. Iphone rendering I've been made to believe is total black texture.