Slow startup when using `gpu-api = vulkan` with NVIDIA

Important Information

• Source of the mpv binary: https://sourceforge.net/projects/mpv-player-windows/files/
• mpv version: mpv-x86_64-v3-20231126-git-6898d57.7z
• Relevant hardware spec: AMD Ryzen 9 5900X, NVIDIA GeForce RTX 3080
• Windows version: 11 23H2 22631.2715
• NVIDIA driver version: 546.17

Reproduction steps

Run on Windows with NVIDIA and setup mpv to use Vulkan as GPU API. This is my config file:

vo = gpu-next
hwdec = nvdec or vulkan
gpu-api = vulkan

Expected behavior

The player starts without a delay.

Actual behavior

The player takes about 2 seconds to start and there are reports of delays when creating Vulkan instance and device:

[vo/gpu-next/libplacebo] Spent 1037.710 ms creating vulkan instance (slow!)

[vo/gpu-next/libplacebo] Spent 350.304 ms creating vulkan device (slow!)

When does it NOT happen

Tested on multiple machines and OS. This does NOT happen in the following situations:

• When running on Linux with AMD using Wayland with the config above
• When running on Windows with AMD with the config above
• When running on Linux with NVIDIA using X11 with the config above
• When running on Windows with NVIDIA (same setup as with the issue) but NOT using Vulkan, for example:

vo = gpu-next
hwdec = nvdec
gpu-api = opengl
gpu-context = win

Log file

The relevant part of the log file (also attached as output.txt):

[vo/gpu-next/vulkan] Initializing GPU context 'winvk'
[vo/gpu-next/libplacebo] Initialized libplacebo v6.338.0-60-g795600a-dirty (API v342)
[vo/gpu-next/libplacebo] Spent 93.897 ms enumerating instance extensions
[vo/gpu-next/libplacebo] Creating vulkan instance with extensions:
[vo/gpu-next/libplacebo]     VK_KHR_get_physical_device_properties2
[vo/gpu-next/libplacebo]     VK_KHR_surface
[vo/gpu-next/libplacebo]     VK_EXT_swapchain_colorspace
[vo/gpu-next/libplacebo]     VK_KHR_external_memory_capabilities
[vo/gpu-next/libplacebo]     VK_KHR_external_semaphore_capabilities
[vo/gpu-next/libplacebo]     VK_KHR_get_surface_capabilities2
[vo/gpu-next/libplacebo]     VK_KHR_portability_enumeration
[vo/gpu-next/libplacebo]     VK_KHR_surface
[vo/gpu-next/libplacebo]     VK_KHR_win32_surface
[vo/gpu-next/libplacebo] Spent 1037.710 ms creating vulkan instance (slow!)
[vo/gpu-next/libplacebo] Probing for vulkan devices:
[vo/gpu-next/libplacebo]     GPU 0: NVIDIA GeForce RTX 3080 v1.3.260 (discrete)
[vo/gpu-next/libplacebo]            uuid: F7:9C:C7:F0:2E:57:EB:B3:87:B4:E8:95:88:06:06:BF
[vo/gpu-next/libplacebo] Vulkan device properties:
[vo/gpu-next/libplacebo]     Device Name: NVIDIA GeForce RTX 3080
[vo/gpu-next/libplacebo]     Device ID: 10de:2206
[vo/gpu-next/libplacebo]     Device UUID: F7:9C:C7:F0:2E:57:EB:B3:87:B4:E8:95:88:06:06:BF
[vo/gpu-next/libplacebo]     Driver version: 88844000
[vo/gpu-next/libplacebo]     API version: 1.3.260
[vo/gpu-next/libplacebo] Using async transfer (queue 1)
[vo/gpu-next/libplacebo] Using async compute (queue 2)
[vo/gpu-next/libplacebo] Creating vulkan device with extensions:
[vo/gpu-next/libplacebo]     VK_KHR_swapchain
[vo/gpu-next/libplacebo]     VK_KHR_swapchain
[vo/gpu-next/libplacebo]     VK_KHR_push_descriptor
[vo/gpu-next/libplacebo]     VK_KHR_external_memory_win32
[vo/gpu-next/libplacebo]     VK_EXT_external_memory_host
[vo/gpu-next/libplacebo]     VK_KHR_external_semaphore_win32
[vo/gpu-next/libplacebo]     VK_EXT_pci_bus_info
[vo/gpu-next/libplacebo]     VK_EXT_hdr_metadata
[vo/gpu-next/libplacebo]     VK_EXT_full_screen_exclusive
[vo/gpu-next/libplacebo]     VK_EXT_descriptor_buffer
[vo/gpu-next/libplacebo]     VK_EXT_shader_atomic_float
[vo/gpu-next/libplacebo]     VK_KHR_video_decode_queue
[vo/gpu-next/libplacebo]     VK_KHR_video_decode_h264
[vo/gpu-next/libplacebo]     VK_KHR_video_decode_h265
[vo/gpu-next/libplacebo]     VK_KHR_video_queue
[vo/gpu-next/libplacebo] Spent 350.304 ms creating vulkan device (slow!)

Sample files

This issue is irrelevant of the media file used.

Start with the gpu-next/libplacebo Vulkan initialization path, especially the winvk context, and compare the instance and device creation timings in the supplied log across the listed Windows and Linux configurations. Done means identifying the cause of the NVIDIA Windows delay and verifying that startup no longer incurs the reported multi-second Vulkan initialization cost.