libmpv renderer backend

[tsl0922]

libmpv provides OpenGL renderer API only, but it does not perform best on all platforms:

• OpenGL is slower than D3D11 on Windows
• Apple deprecates OpenGL on macOS
• Does not support gpu-next yet: Support for libplacebo (gpu-next) in the rendering API mpv-player/mpv#10810

Upstream feature requests: D3D11, Vulkan

Luckily, we can use translation layer like ANGLE, which may translate OpenGL ES API calls to a faster hardware-supported APIs to improve performance. Also, ANGLE makes ImPlay work on Virtual Machines that doesn't have a OpenGL 3 driver (example: HyperV vm has D3D driver only). The downside is, it may break HDR: mpv-player/mpv#8530

I've implemented OpenGL ES 2.0 support on the latest main branch, and it's now built in actions (tested the windows version).

NOTE: EGL and GLESv2 dynamic libraries is required to run the GLES2 version of ImPlay, but not needed at build time.

[tsl0922]

The GLES2 version is now built as default on windows in actions.

[dragonflylee]

here is my implement of d3d11 api for mpv
https://github.com/dragonflylee/mingw-packages/blob/dev/mpv/0001-d3d11-render.patch

and example https://gist.github.com/dragonflylee/5b73c0df5db85dba03488d592f1af23a

[tsl0922]

Thanks. I don't want to use a patched mpv, and ANGLE works fine.

[dragonflylee]

But hwaccel didn't work correctly on my Yoga730 (i5-8250u UHD620), and fallback to dxva2-copy,
Test log below

ImPlay.com --terminal=yes --gpu-context=angle "D:\[Sakurato] Spy x Family S2 - 01.mkv"
[libmpv_render/dxva2-egl] Failed to create EGL surface
Cannot load nvcuda.dll
 (+) Video --vid=1 (*) (hevc 1920x1080 23.976fps)
 (+) Audio --aid=1 --alang=jpn (*) 'Audio' (aac 2ch 44100Hz)
 (+) Subs  --sid=1 --slang=chi (*) '[桜都字幕组] Simplified Chinese' (ass)
     Subs  --sid=2 --slang=chi '[桜都字幕组] Traditional Chinese' (ass)
File tags:
 Comment: Auto Video Processor 3.0.04 @Sakurato
Using hardware decoding (dxva2-copy).
AO: [wasapi] 48000Hz stereo 2ch float
VO: [libmpv] 1920x1080 p010
[libmpv_render] after creating texture: OpenGL error INVALID_FRAMEBUFFER_OPERATION.
Option af-remove: item label @aeq not found.

[tsl0922]

You don't need to specify gpu-context, it should select d3d11va-copy automatically.

[tsl0922]

Currently, both the video and gui are rendering with OpenGL. To add another backend for mpv, we need to add it for imgui too. It means a lot of work to me, so I'm also considering to use the window embeding feature of mpv (--wid).

[teohhanhui]

They don't have a way to make --wid work with Wayland yet...

mpv-player/mpv#10810 (comment)