fix(portal): recover AVDRMFrameDescriptor before encode_frame to prevent leak on error

src/state_portal.rs

@@ -188,19 +188,22 @@ impl StatePortal {
             (*hw_frame.as_mut_ptr()).pts = pts;
         }
 
-        // 8. Encode
-        enc.encode_frame(&hw_frame)?;
-
-        // 9. Clean up: recover the Boxed descriptor from raw_frame to prevent leak.
-        //    Video::drop calls av_frame_free which does NOT free data[0].
+        // 8. Recover the Boxed descriptor from raw_frame *before* encoding.
+        //    av_hwframe_transfer_data has already imported the DMA-BUF into the
+        //    VAAPI surface, so FFmpeg no longer references the descriptor struct.
+        //    Doing this before encode_frame ensures the descriptor is reclaimed
+        //    even if encode_frame returns early via `?`.
         unsafe {
             let desc_ptr = (*raw_frame.as_ptr()).data[0] as *mut ffi::AVDRMFrameDescriptor;
             if !desc_ptr.is_null() {
                 let _ = Box::from_raw(desc_ptr);
             }
         }
-        // raw_frame and hw_frame drop here via Video::drop → av_frame_free
 
+        // 9. Encode — safe to early-return via `?` now that descriptor is recovered.
+        enc.encode_frame(&hw_frame)?;
+
+        // raw_frame and hw_frame drop here via Video::drop → av_frame_free
         Ok(())
     }