Kodi video playback freezes when grabbing 4K on Raspberry Pi 5

[joopdo]

When running the grabber on Raspberry Pi 5 with Kodi 22 (using directtoplane video rendering), video playback freezes after a few seconds playing 4K video. Audio continues, but video output stops updating.

Environment:

• Raspberry Pi 5
• Kodi 22 (LibreELEC)
• drm-vc4-grabber v0.1.2
• HyperHDR integration
• Kodi video renderer: directtoplane

2025-12-06 16:41:42.531 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 149 to gem handle 0, ret = -1
2025-12-06 16:41:42.565 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 82 to gem handle 0, ret = -1
2025-12-06 16:41:42.615 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 141 to gem handle 0, ret = -1
2025-12-06 16:41:42.648 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 148 to gem handle 0, ret = -1
2025-12-06 16:41:42.698 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 147 to gem handle 0, ret = -1
2025-12-06 16:41:42.731 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 150 to gem handle 0, ret = -1
2025-12-06 16:41:42.781 T:16777   error <general>: CVideoLayerBridgeDRMPRIME::Map - failed to convert prime fd 140 to gem handle 0, ret = -1

When I disable, it plays fine.

[joopdo]

Update: Root Cause Identified and Workaround Implemented

After extensive testing, I've identified that the issue specifically affects 4K content only. HD content (1080p and below) works perfectly with the grabber running simultaneously.
Root Cause

The Raspberry Pi 5's GPU has insufficient memory bandwidth to handle both 4K HEVC/HDR video decoding with drm-vc4-grabber. This causes PRIME fd handle exhaustion, leading to the video freeze while audio continues.
Implemented Workaround

I've modified the grabber to detect 4K content and pause capture during 4K playback:

// Detect 4K content
let is_4k = fbinfo.width >= 3840 || fbinfo.height >= 2160;

if is_4k {
    // Send static warm color to HyperHDR
    send_color_warm(&mut socket, verbose);
    // Skip capture, just sleep
    thread::sleep(Duration::from_secs(1));
    continue;
}

[joopdo]

Made a PR here with the draft chenges: #34

[joopdo]

Actually, I found the issue with 4K also happened on 1080p sometimes. With some changes in the PR, I am now testing and it seems more stable, even in 4K, so no need to sleep during 4K video. 🥳

[joopdo]

It seems stable for me!