Bug 162528 – [GTK][ThreadedCompositor] Some videos are not rendered correctly

• Component: WebKitGTK
• Status: RESOLVED DUPLICATE

[Guilaume Ayoub]

Created attachment 289744 [details]
Screenshot with thumbnail of the correct rendering

Some videos (on Youtube for example) are not displayed correctly. For example:

https://www.youtube.com/watch?v=Y6jrVg_Mz8Y

The problem can be seen when this video is played with 360p resolution, but not with 240p. It looks like a 3D texture bug.

I don't remember exactly when whis bug appeared, but it was probably during the 2.13.x releases. I can bisect if needed.

[Michael Catanzaro]

(In reply to comment #0)
> I can bisect if needed.

This would be awesome!

[Guilaume Ayoub]

The bug has been introduced by 2.13.4 (2.13.3 works well). I'm cloning the repository to find the bad commit.

[Guilaume Ayoub]

(In reply to comment #2)
> I'm cloning the repository to find the bad commit.

I was a bit optimistic. Bisecting the error is probably too long and I don't even know the commits corresponding to the WebkitGTK versions.

Judging from the 2.13.4 changelog, I've tried to deactivate the threaded compositor (using WEBKIT_DISABLE_COMPOSITING_MODE), but it doesn't solve the problem.

I'm trying to find the commit in the git log.

[Michael Catanzaro]

(In reply to comment #3)
> I was a bit optimistic. Bisecting the error is probably too long and I don't
> even know the commits corresponding to the WebkitGTK versions.

Those releases were unusually close together, so there are only ~400 revisions to bisect. 2.13.3 is r203344 and 2.13.4 is r203768.

[Guilaume Ayoub]

I've spent a lot of time bisecting and I should have cleaned the directory: keeping the compiled stuff between 2.13.3 and 2.13.4 made me compile a 2.13.4 (and even a 2.14.0) without the bug. :'(.

Of course, when I build from a fresh clone, the bug comes back.

I'll bisect and *clean before each compilation* soon!

[Guilaume Ayoub]

This video is another strange example:

http://www.todaypost.cf/2016/10/ascii-fluid-dynamics.html

The video is OK from 00:00 to 00:10, and then suddenly gets the problem. If I click on the timeline, it:
- sometimes plays the video with the problem, or
- sometimes draws 1 frame without the problem and crashes.

I didn't give up the idea of a clean bisect, but I need some time…

[Guilaume Ayoub]

I've bisected, the bug is in revision 203596:

[GTK] Enable threaded compositor by default
https://bugs.webkit.org/show_bug.cgi?id=160079

I don't know why setting WEBKIT_DISABLE_COMPOSITING_MODE didn't help to find this before… Can I do anything to help?

[Miguel Gomez]

I've been trying to reproduce this both with ToT and with r203596, but I'm not able to. Both videos work fine for me using the MiniBrowser.

What I do see is that in the second video, when reaching second 10 more or less, the resolution increases from 320x240 to 472x352, which could be related to the problem.

[Guilaume Ayoub]

The bug is caused by gstreamer-plugins-vaapi, everything's OK when I remove it.

[Guilaume Ayoub]

Full report:

- With gst-plugins-vaapi:

  - Some videos always work, with Webkit and Totem, X or Wayland.
  - Other videos:
    - work with Totem + X,
    - don't work with Totem + Wayland: black window,
    - don't work with Webkit (X or Wayland): problem shown in attachment.

- Without gst-plugins-vaapi: everything works.

Of course, this bug is not really important, I can remove gst-plugins-vaapi. But if anyone is interested in solving it, I can test whatever you want.

[Víctor M. Jáquez L.]

It seems that, when uploading the frame into the texture, the stride is not set correctly.

If you use glimagesink, it works ok:

gst-play-1.0 "https://r2---sn-5ngj5cax-nj9e.googlevideo.com/videoplayback?id=o-AD13jcfJkAy9WFFIbSoYLUsKHcahpcBrxIPF62BHWOqV&ipbits=0&gcr=es&pcm2cms=yes&requiressl=yes&ip=91.117.99.155&sparams=dur%2Cei%2Cgcr%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpcm2cms%2Cpl%2Cratebypass%2Crequiressl%2Csource%2Cupn%2Cexpire&upn=ccGiZYKzI2I&ms=au&itag=43&ei=yRsKWNnGI8PrWra-gtAI&mv=m&mt=1477057351&mn=sn-5ngj5cax-nj9e&mm=31&expire=1477079081&pl=26&mime=video%2Fwebm&key=yt6&lmt=1380754974815688&dur=0.000&ratebypass=yes&source=youtube&initcwndbps=2682500&signature=2DB6C17595F6E2273EBC1DADF0C06DFC54B2923B.DEA755C631A54E0D4CAFA833ABB807C5BF3F9EF1" --videosink=glimagesink

Perhaps webkitsink misses something in that regard. I'd need to check.

[Víctor M. Jáquez L.]

(In reply to comment #10)
>
>     - don't work with Totem + Wayland: black window,

Known issue: https://bugzilla.gnome.org/show_bug.cgi?id=772838

[Guilaume Ayoub]

Does your fix in Gstreamer-vaapi 1.11.3 fix this problem too?

[Víctor M. Jáquez L.]

*** This bug has been marked as a duplicate of bug 173796 ***