Bug#992841: obs-studio: fails to ouput to V4L loopback device. Black Screen if loopback device used by video application.

[Frank Ehmsen <frank@eh-is.de>]

Package: obs-studio
Version: 26.1.2+dfsg1-2
Severity: normal

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
     I wanted to use obs-studio with Zoom or Microsoft Teams. I am also
     a user of the package nvidia-driver.

   * What exactly did you do (or not do) that was effective (or
     ineffective)?
     I installed v4l2loopback-dkms before starting obs-studio,
     configured my scene in obs-studio and hit the button "start virtual
     camera". 

   * What was the outcome of this action?
     The virtual video device appeared in Zoom or Microsoft Teams, but
     shows only a black screen.

   * What outcome did you expect instead?
     The virtual camera device should show the configured scene from
     obs-studio.

-- System Information:
Debian Release: 11.0
  APT prefers stable-security
  APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-8-amd64 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages obs-studio depends on:
ii  libavcodec58      7:4.3.2-0+deb11u2
ii  libavdevice58     7:4.3.2-0+deb11u2
ii  libavformat58     7:4.3.2-0+deb11u2
ii  libavutil56       7:4.3.2-0+deb11u2
ii  libc6             2.31-13
ii  libcurl3-gnutls   7.74.0-1.3+b1
ii  libfontconfig1    2.13.1-4.2
ii  libfreetype6      2.10.4+dfsg-1
ii  libgcc-s1         10.2.1-6
ii  libjansson4       2.13.1-1.1
ii  libluajit-5.1-2   2.1.0~beta3+dfsg-5.3
ii  libmbedcrypto3    2.16.9-0.1
ii  libmbedtls12      2.16.9-0.1
ii  libmbedx509-0     2.16.9-0.1
ii  libobs0           26.1.2+dfsg1-2
ii  libpulse0         14.2-2
ii  libpython3.9      3.9.2-1
ii  libqt5core5a      5.15.2+dfsg-9
ii  libqt5gui5        5.15.2+dfsg-9
ii  libqt5svg5        5.15.2-3
ii  libqt5widgets5    5.15.2+dfsg-9
ii  libqt5x11extras5  5.15.2-2
ii  libqt5xml5        5.15.2+dfsg-9
ii  libspeexdsp1      1.2~rc1.2-1.1
ii  libstdc++6        10.2.1-6
ii  libswscale5       7:4.3.2-0+deb11u2
ii  libudev1          247.3-6
ii  libv4l-0          1.20.0-2
ii  libx11-6          2:1.7.2-1
ii  libx264-160       2:0.160.3011+gitcde9a93-2.1
ii  libxcb-randr0     1.14-3
ii  libxcb-shm0       1.14-3
ii  libxcb-xfixes0    1.14-3
ii  libxcb-xinerama0  1.14-3
ii  libxcb1           1.14-3
ii  libxcomposite1    1:0.4.5-1
ii  libxfixes3        1:5.0.3-2
ii  python3           3.9.2-3
ii  python3.9         3.9.2-1

Versions of packages obs-studio recommends:
ii  obs-plugins  26.1.2+dfsg1-2

Versions of packages obs-studio suggests:
ii  policykit-1        0.105-31
ii  v4l2loopback-dkms  0.12.5-1

-- no debconf information