I've downloaded the following video in webm format from YouTube:

https://www.youtube.com/watch?v=ar5toq-E-5M

VLC opens a window with the right size (though it doesn't fit
on my screen due to the window decorations: this is 3840x2160),
but cannot display anything: this is entirely black.

Audio is fine.

In the terminal, I can see:

libva info: VA-API version 1.22.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_22
libva info: va_openDriver() returns 0
libva info: VA-API version 1.22.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_22
libva info: va_openDriver() returns 0
[00007f8010ca70f0] avcodec decoder: Using OpenGL/VAAPI backend for VDPAU for hardware decoding
[00007f8010ca70f0] main decoder error: buffer deadlock prevented

According to the media information, the video codec is
AOMedia's AV1 Video (av01).

Firefox can play this video (by opening the webm file directly,
without going via YouTube). The FFplay media player (ffplay)
can play it too.

Note that I could play videos from the same YouTube channel with VLC
in the past (a few weeks ago). But I don't know whether something has
changed.

	Hi,

Le tiistaina 26. elokuuta 2025, 21.47.31 Itä-Euroopan kesäaika Vincent Lefevre
a écrit :
likely unwittingly as a suggestion of another package.

I don't know why Debian carries that proof of concept, as it is half-assed
harmful garbage as far as users are concerned. So please:
- reassign your bug to that package,
- uninstall that from your system.

This is not a VLC issue.

Br,

Raising the severity because this breaks another package (vlc).

qaa:~> aptitude why libvdpau-va-gl1
i   gstreamer1.0-libav Depends    libavutil59 (>= 7:7.0)
i A libavutil59        Depends    libvdpau1 (>= 0.2)
i A libvdpau1          Recommends vdpau-driver-all | vdpau-driver
i A vdpau-driver-all   Depends    libvdpau-va-gl1

Since the goal of vdpau-driver-all is "This package depends on the
full suite of drivers for the VDPAU API.", I suppose that the issue
comes from libvdpau1, which should not recommend vdpau-driver-all
(perhaps only drivers that are known to work).

Or perhaps libvdpau-va-gl1 should just be removed from Debian
(with the vdpau-driver-all dependency updated): the latest
upstream was in 2016, and the package description is probably
out-of-date.

Even though recommended packages can be removed, broken packages
should never be installed by default.

Control: reassign -1 libvdpau-va-gl1 0.4.2-2
Control: affects -1 + src:vlc

Let's start by having a RC bug against libvdpau-va-gl1. Then we can
consider dropping it from vdpau-driver-all.

Does this bug also affect trixie?

Andreas

I don't know yet. But I've attached a small testcase (this is
an ogv video that I've converted to webm with ffmpeg using the
"-codec:v av1" option), on which I can reproduce the issue:
still a black screen (note that the audio stream is silent,
but audio isn't concerned by the bug).

So, perhaps users with a trixie machine may reproduce it or not.
I don't know whether this depends on the hardware.

to make clear that the current bug is about libvdpau-va-gl1.
vdpau-driver-all, this is not the default VDPAU driver:
/etc/X11/Xsession.d/20vdpau-va-gl contains
------------------------------------------------------------------------
# To enable the use of libvdpau-va-gl as the default VDPAU driver,
# uncommont the following lines. See
# `/usr/share/doc/libvdpau-va-gl1/README.Debian` for more details.

# [ ! -f /usr/lib/$(arch)-$(uname -s | tr '[A-Z]' '[a-z]')-gnu/vdpau/libvdpau_va_gl.so.1 ] || \
#   export VDPAU_DRIVER=va_gl
------------------------------------------------------------------------

So I don't understand why it is used.

We believe that the bug you reported is fixed in the latest version of
libvdpau, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1112130@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Andreas Beckmann <anbe@debian.org> (supplier of updated libvdpau package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 30 Dec 2025 02:17:36 +0100
Source: libvdpau
Architecture: source
Version: 1.5-4
Distribution: unstable
Urgency: medium
Maintainer: Debian NVIDIA Maintainers <pkg-nvidia-devel@lists.alioth.debian.org>
Changed-By: Andreas Beckmann <anbe@debian.org>
Closes: 1112130 1124004
Changes:
 libvdpau (1.5-4) unstable; urgency=medium
 .
   [ Andreas Beckmann ]
   * Drop vdpau-driver-all package, no more drivers to depend on.
     - libvdpau-va-gl1 breaks vlc.  (Closes: #1112130)
     - mesa-vdpau-drivers has been removed.  (Closes: #1124004)
   * libvdpau1: Drop driver recommendation, no suitable drivers in main.
   * Bump Standards-Version to 4.7.2. No changes needed.
   * Drop redundant Rules-Requires-Root: no.
 .
   [ Luca Boccassi ]
   * Remove myself from Uploaders.
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