The NV12→RGB pass hardcoded BT.709, so SD (BT.601) clips had slightly wrong hues.
Read each frame's AVColorSpace in the importer and derive the Y'CbCr→R'G'B'
matrix (BT.709/601/240M/2020; Unspecified guessed by height like swscale/players),
carry the four coefficients on GpuVideoFrame, and apply them in the shader.
- core: GpuVideoFrame.coeffs + ycbcr_coeffs(kr, kb) helper.
- hw_video.rs: map AVColorSpace → (kr, kb) → coeffs.
- nv12_blit{.rs,.wgsl}: uniform grows to 80 bytes (adds a coeffs vec4); the matrix
multiply uses params.coeffs instead of literals.
BT.2020's transfer is still approximated as sRGB. The DRM-modifier-without-SAMPLED case stays a graceful software fallback.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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