Video flickering with hardware acceleration enabled on YouTube

[bnema]

Description

There is still flickering observed when playing videos on YouTube with hardware acceleration enabled.

Technical Context

The application has extensive hardware acceleration controls in:

• internal/infrastructure/webkit/settings.go - WebKit hardware acceleration policies
• internal/infrastructure/env/manager.go - GPU vendor detection (AMD/Intel/NVIDIA) and environment variable configuration
• internal/infrastructure/media/diagnostics.go - GStreamer plugin and VA-API driver detection

Key settings involved:

• HardwareAccelerationPolicyAlwaysValue for WebKit
• VA-API driver selection (radeonsi, iHD, nvidia)
• GStreamer GL API settings (GST_GL_API)
• Compositor settings (WEBKIT_FORCE_COMPOSITING_MODE)
• VSync settings (__GL_SYNC_TO_VBLANK, vblank_mode)

Possible Causes

• VSync mismatch between GStreamer video pipeline and WebKit compositor
• Incorrect GL API selection for the GPU vendor
• DMA-BUF renderer issues (controlled by WEBKIT_DISABLE_DMABUF_RENDERER)
• GSK renderer compatibility with video overlays

Investigation Areas

• Check if issue is GPU vendor-specific
• Test with different gsk_renderer values (opengl, vulkan, cairo)
• Verify VSync configuration
• Test with hardware_decoding: disable to isolate video decoder vs compositor issue