Bug 2214267

Summary: Broken H264 decoding since Firefox 114
Product: [Fedora] Fedora Reporter: Robert Vazan <robert.vazan>
Component: firefoxAssignee: Gecko Maintainer <gecko-bugs-nobody>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: unspecified    
Version: 37CC: erack, gecko-bugs-nobody, jhorak, klaas, rstrode, stransky
Target Milestone: ---Keywords: Desktop, Regression
Target Release: ---   
Hardware: x86_64   
OS: Linux   
URL: https://www.imdb.com/title/tt9362722/
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
Screencast demonstrating the issue
none
about:support
none
glxinfo > gfxlog.txt 2>&1 none

Description Robert Vazan 2023-06-12 12:36:29 UTC 
Upgrade to Firefox 114 broke H264 video decoding. Videos are now extremely jerky, jumping forth and back as if frames were reordered. Not all H264 videos are broken. For example, on IMDb, autoplaying trailers on movie homepage are broken, but clicking through to the dedicaded trailer page gives you smooth playback. YouTube videos are also all broken if they are in H264 format. Perhaps it has to do with the complexity of layout on and around the video.

Reproducible: Always

Steps to Reproduce:
The most reliable way to reproduce the issue is to look at IMDb autoplay trailers on movie homepages.



Here's what I tried so far:

- Reverting to Firefox 113 fixes the issue, but that's obviously an impractical workaround.
- Wayland/X11 switch has no effect.
- Software/hardware WebRender switch has no effect.
- My HW does not support video decoding, but I disabled it for a while anyway and the change had no effect.
- Safe mode has no effect.
- Clean profile has no effect.

Diagnostic data and screencast are available.
Comment 1 Robert Vazan 2023-06-12 12:37:48 UTC 
Created attachment 1970410 [details]
Screencast demonstrating the issue
Comment 2 Robert Vazan 2023-06-12 12:41:12 UTC 
Created attachment 1970411 [details]
about:support
Comment 3 Robert Vazan 2023-06-12 12:42:12 UTC 
Created attachment 1970416 [details]
glxinfo > gfxlog.txt 2>&1
Comment 4 Robert Vazan 2023-06-12 12:45:43 UTC 
I will try to upgrade to F38, but seeing as this is related to upgrade of Firefox package, I suspect upgrade to F38 will not help.
Comment 5 Martin Stransky 2023-06-19 10:38:13 UTC 
Can you try to install ffmpeg from rpmfusion?
See https://fedoraproject.org/wiki/Firefox_Hardware_acceleration for details.
Thanks.
Comment 6 Robert Vazan 2023-07-18 17:04:42 UTC 
When HW acceleration is installed according to the instructions, there is no jitter. This fixes the problem for me. I still don't understand why would software video decoding fail so catastrophically. Isn't software decoding meant to be the safe fallback?
Comment 7 Martin Stransky 2023-07-19 08:44:16 UTC 
(In reply to Robert Vazan from comment #6)
> When HW acceleration is installed according to the instructions, there is no
> jitter. This fixes the problem for me. I still don't understand why would
> software video decoding fail so catastrophically. Isn't software decoding
> meant to be the safe fallback?

Unless it's OpenH264 meant for WebRTC only.