[clemenswasser]

Adds HDR10/HLG output to the Android GL backend: set_color switches the
ANativeWindow dataspace and recreates the EGL surface with the matching
EGL_GL_COLORSPACE_*_EXT, and preferred_csp detects HDR displays so
--target-colorspace-hint=auto works without the embedding app passing
anything.

Android always reports the panel capability, so the default target hint
mode also renders SDR into the HDR container.
--target-colorspace-hint-mode=source keeps SDR as SDR.

The NDK has no HDR capability query, so this goes through JNI and depends on
the hidden ActivityThread.currentApplication() API.

Tested on a Galaxy Tab S9: DV/HDR10 -> BT2020/PQ at 540 nits,
HLG -> BT2020/HLG.

AI disclosure: developed with DeepSeek V4.1 Flash 1017 running in OpenCode.
I reviewed the changes and ran the tests above on the device.

[kasper93]

Duplicate of: #18710

And my review does not change from the other one. This should be implemented using EGL extensions (which are builtin on Android) in libplacebo as colorspace hint, which the same way as Vulkan and d3d11. Then there is zero changes needed in mpv.

[clemenswasser]

@kasper93 Sorry, I did not check for duplicates before opening this. I'll close this and redo the
work in libplacebo.

On Android, eglSurfaceAttrib(EGL_GL_COLORSPACE_KHR, ...) is not usable: on the Adreno 740 it returns
EGL_BAD_ATTRIBUTE, because libEGL only honors the colorspace in eglCreateWindowSurface. The only
way to change it on a live surface is ANativeWindow_setBuffersDataSpace(), which is the same call
libEGL makes when it creates the surface from a colorspace attribute. Setting ADATASPACE_BT2020_PQ
moved the layer to dataspace=BT2020_PQ without recreating the surface.

So I plan to pass the native window to the GL swapchain, which lets colorspace_hint set the dataspace
and the SMPTE2086/CTA861 metadata without owning the surface. mpv would only pass the window through.
The metadata needs no Android API, eglSurfaceAttrib supports it.

Does that work for you? target-colorspace-hint=auto also needs preferred_csp(), an existing
ra_ctx_params hook, so I would keep the Android implementation of it.

[kasper93]

@kasper93 Sorry, I did not check for duplicates before opening this. I'll close this and redo the work in libplacebo.

On Android, eglSurfaceAttrib(EGL_GL_COLORSPACE_KHR, ...) is not usable: on the Adreno 740 it returns EGL_BAD_ATTRIBUTE, because libEGL only honors the colorspace in eglCreateWindowSurface. The only way to change it on a live surface is ANativeWindow_setBuffersDataSpace(), which is the same call libEGL makes when it creates the surface from a colorspace attribute. Setting ADATASPACE_BT2020_PQ moved the layer to dataspace=BT2020_PQ without recreating the surface.

So I plan to pass the native window to the GL swapchain, which lets colorspace_hint set the dataspace and the SMPTE2086/CTA861 metadata without owning the surface. mpv would only pass the window through. The metadata needs no Android API, eglSurfaceAttrib supports it.

Does that work for you? target-colorspace-hint=auto also needs preferred_csp(), an existing ra_ctx_params hook, so I would keep the Android implementation of it.

I cannot comment on the details, because I would have to look closely into it. But the general idea is that we implement colorspace_hint in libplacebo, using what's needed for that EGL_EXT_surface_SMPTE2086_metadata, EGL_EXT_surface_CTA861_3_metadata, EGL_EXT_gl_colorspace_bt2020_pq, EGL_EXT_gl_colorspace_bt2020_hlg, seems like the things to use.

Then indeed like you said the preferred_csp() implementation is on the mpv side of things. But this is not directly related, because, the =source mode doesn't need it at all for example. Either way, it's good to have to have proper default output based on the display parameters.

We can discuss the details after there is better initial shape.

[clemenswasser]

@kasper93 Implemented in libplacebo: https://code.videolan.org/videolan/libplacebo/-/merge_requests/940