FFMPEG crashes since switching to AMD hardware

Help
1

Since updating hardware (5600X to 9800X3D and 1080 to 9070XT) I have been unable to make ffmpeg video encoding work on the new machine.

When using the CPU (libsvtav1) ffmpeg works as expected until I run a second ffmpeg process, or open a Steam application, at which point the encoding stops with no error, and Steam restarts itself. This did not happen with the 5600X.

When using the GPU (av1_amf) ffmpeg crashes:

radv: RADV_PERFTEST=video_decode is deprecated and will be removed in future Mesa releases. Please use RADV_EXPERIMENTAL=video_decode instead.
WARNING: radv is not a conformant Vulkan implementation, testing use only.
zsh: segmentation fault (core dumped)

I have not altered my NixOS config since previous hardware iteration, where encoding worked, with the exception of adding the AMD bits below.

  nixpkgs.config.rocmSupport = true;
  
  hardware = {
    cpu.amd.updateMicrocode = true;
    amdgpu = {
      initrd.enable = true;
      opencl.enable = true;
    };
    graphics = {
      enable = true;
      enable32Bit = true;
      extraPackages = [pkgs.amf];
    };
  };

I am using the ffmpeg-full version, which was sufficient for encoding with the previous hardware.

What could be causing these issues?

2

That makes it sound like zsh is crashing?

3

I would suggest setting some additional ffmpeg options, like verbose logging to see what ffmpeg is trying to do. Additionally you can use -hwaccel to switch between vaapi and vulcan backends to see which is problematic. Finally, you can use -hwaccel_device to figure out if the problem is using the CPU’s media accelerator or the GPU’s accelerator.

Option Description
-loglevel verbose Provides detailed information about the processing.
-hwaccel Specifies the hardware acceleration method to use.
-hwaccel_device Defines the device to be used for hardware acceleration.
4

Happens in bash and sh as well.

Unfortunately the verbose output doesn’t seem to add anything other than some version information:

radv: RADV_PERFTEST=video_decode is deprecated and will be removed in future Mesa releases. Please use RADV_EXPERIMENTAL=video_decode instead.
WARNING: radv is not a conformant Vulkan implementation, testing use only.
0126-06-30 23:28:16 9FFFF6C0 [AMFDeviceVulkanImpl]    Info: Version of the Vulkan driver:  26.1.5
0126-06-30 23:28:16 9FFFF6C0 [AMFDeviceVulkanImpl]    Info: Highest version of the Vulkan API that is supported by the physical device: 1.4.354
Segmentation fault         (core dumped) ffmpeg -loglevel verbose -hwaccel vaapi -i 1.mp4 -c:v av1_amf -crf 30 -preset 6 -svtav1-params keyint=10s:tune=0:enable-overlays=1 -c:a libopus -b:a 128k 1.mkv

As for switching between vaapi and vulkan, both end in the crash/output above. This is with the GPU . The CPU issue seem unrelated, since it doesn’t produce an instant crash and does work for a while before silently dying.