diff --git a/module/gmp-openh264.cpp b/module/gmp-openh264.cpp
index 9c3ba297..bed75f13 100644
--- a/module/gmp-openh264.cpp
+++ b/module/gmp-openh264.cpp
@@ -342,6 +342,11 @@ class OpenH264VideoEncoder : public GMPVideoEncoder {
     }
 
     if (!has_frame) {
+      // This frame must be destroyed on the main thread.
+      g_platform_api->syncrunonmainthread (WrapTask (
+                                             this,
+                                             &OpenH264VideoEncoder::DestroyInputFrame_m,
+                                             inputImage));
       return;
     }
 
@@ -420,6 +425,11 @@ class OpenH264VideoEncoder : public GMPVideoEncoder {
     stats_.FrameOut();
   }
 
+  // These frames must be destroyed on the main thread.
+  void DestroyInputFrame_m (GMPVideoi420Frame* frame) {
+    frame->Destroy();
+  }
+
   virtual GMPVideoErr SetChannelParameters (uint32_t aPacketLoss, uint32_t aRTT) {
     return GMPVideoNoErr;
   }