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[Launchpad Bug Tracker <2127792@xxxxxxxxxxxxxxxxxx>]

** Merge proposal linked:
   https://code.launchpad.net/~antoinelassagne/ubuntu/+source/gnome-remote-desktop/+git/gnome-remote-desktop/+merge/494934

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https://bugs.launchpad.net/bugs/2127792

Title:
  Images are corrupted on blackwell GPUs

Status in gnome-remote-desktop package in Ubuntu:
  Fix Released
Status in gnome-remote-desktop source package in Noble:
  In Progress
Status in gnome-remote-desktop source package in Plucky:
  In Progress
Status in gnome-remote-desktop source package in Questing:
  In Progress
Status in gnome-remote-desktop source package in Resolute:
  Fix Released

Bug description:
  There is image distorsion in gnome-remote-desktop when a Blackwell GPU
  is in use and NVENC is responsible for the video streaming.

  Upstream issue: https://gitlab.gnome.org/GNOME/gnome-remote-
  desktop/-/issues/263

  A fix was just released by nvidia upstream, and also backported to GNOME 48: https://gitlab.gnome.org/GNOME/gnome-remote-desktop/-/merge_requests/344
  https://gitlab.gnome.org/GNOME/gnome-remote-desktop/-/merge_requests/346

  ---------------------------
  SRU Justification:

  [ Impact ]

   * This is a hardware enablement SRU.

   * gnome-remote-desktop, when used alongside NVENC for video
  streaming, simply does not work, because the image is broken.

   * With the above, the streaming is fixed.

  [ Fix ]

   * Nvidia devices never supported `NV_ENC_PARAMS_FRAME_FIELD_MODE_MBAFF`.
  Though the code worked for past, it causes interlaced line artifacts on
  Blackwell GPUs.

  * Using `NV_ENC_PARAMS_FRAME_FIELD_MODE_FRAME` and changing
  `grd-cuda-avc-utils` to produce progressive frames works on
  Blackwell and on older GPU generations.

  [ Test Plan ]

   * Test gnome-remote-desktop with and without the fix. Make sure which
  backend is in use. This can be checked by running `nvidia-smi dmon`
  and observing an encoder activity >0%. The repro only occurs when the
  NVENC path is used. CPU encoding path or non-H264 streaming is
  unaffected

  * Run the same test on an older GPU generation (Maxwell, ideally)

  
  [ Where problems could occur ]

   * Given the nature of the fix, it should not impact non-nvidia machines.
   * Also, the  fix comes from nvidia themsleves, and it's in GNOME 48 and 49 already, so it's pretty safe.

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