diff --git a/lightningbeam-ui/lightningbeam-core/src/video.rs b/lightningbeam-ui/lightningbeam-core/src/video.rs
index 31c31ce..8fb8552 100644
--- a/lightningbeam-ui/lightningbeam-core/src/video.rs
+++ b/lightningbeam-ui/lightningbeam-core/src/video.rs
@@ -460,6 +460,27 @@ impl VideoDecoder {
                         if gpu_out {
                             // Hardware + GPU consumer: import the VAAPI surface as wgpu NV12 textures
                             // (no CPU copy).
+                            // VAAPI hw frames often don't carry the stream's colour tags, so the
+                            // importer (which only sees the frame) would mis-detect transfer/gamut.
+                            // Copy the authoritative values from the codec context (parsed from the
+                            // bitstream) onto the frame when it left them unspecified.
+                            unsafe {
+                                use ffmpeg::ffi::*;
+                                let fp = frame.as_mut_ptr();
+                                let cp = decoder.as_ptr();
+                                if (*fp).color_trc == AVColorTransferCharacteristic::AVCOL_TRC_UNSPECIFIED {
+                                    (*fp).color_trc = (*cp).color_trc;
+                                }
+                                if (*fp).color_primaries == AVColorPrimaries::AVCOL_PRI_UNSPECIFIED {
+                                    (*fp).color_primaries = (*cp).color_primaries;
+                                }
+                                if (*fp).colorspace == AVColorSpace::AVCOL_SPC_UNSPECIFIED {
+                                    (*fp).colorspace = (*cp).colorspace;
+                                }
+                                if (*fp).color_range == AVColorRange::AVCOL_RANGE_UNSPECIFIED {
+                                    (*fp).color_range = (*cp).color_range;
+                                }
+                            }
                             let importer = self.importer.as_ref().unwrap();
                             match unsafe { importer.import(frame.as_mut_ptr() as *mut std::ffi::c_void) } {
                                 Some(gpu) => {
diff --git a/lightningbeam-ui/lightningbeam-editor/src/hw_video.rs b/lightningbeam-ui/lightningbeam-editor/src/hw_video.rs
index f3226d6..2f349f9 100644
--- a/lightningbeam-ui/lightningbeam-editor/src/hw_video.rs
+++ b/lightningbeam-ui/lightningbeam-editor/src/hw_video.rs
@@ -17,6 +17,8 @@ use std::sync::{Arc, Mutex};
 struct SharedHwImporter {
     device: wgpu::Device,
     adapter: wgpu::Adapter,
+    /// Log the detected colour info once (under LB_VIDEO_DEBUG) rather than per frame.
+    logged: std::sync::atomic::AtomicBool,
 }
 
 impl HwVideoImporter for SharedHwImporter {
@@ -99,6 +101,16 @@ impl HwVideoImporter for SharedHwImporter {
         };
         let coeffs = ycbcr_coeffs(kr, kb);
 
+        if std::env::var("LB_VIDEO_DEBUG").is_ok()
+            && !self.logged.swap(true, std::sync::atomic::Ordering::Relaxed)
+        {
+            eprintln!(
+                "[hw_video] {}x{} ten_bit={} full_range={} colorspace={:?} primaries={:?} trc={:?}",
+                width, height, ten_bit, full_range,
+                (*frame).colorspace, (*frame).color_primaries, (*frame).color_trc,
+            );
+        }
+
         // Transfer characteristic → which EOTF the compositor applies to reach scene-linear.
         let transfer = match (*frame).color_trc {
             ff::AVColorTransferCharacteristic::AVCOL_TRC_SMPTE2084 => VideoTransfer::Pq,
@@ -143,6 +155,7 @@ pub fn install(vm: &Arc<Mutex<VideoManager>>, device: &wgpu::Device, adapter: &w
             let importer = Arc::new(SharedHwImporter {
                 device: device.clone(),
                 adapter: adapter.clone(),
+                logged: std::sync::atomic::AtomicBool::new(false),
             });
             if let Ok(mut vm) = vm.lock() {
                 vm.set_hardware_decode(