diff --git a/media/libvpx/libvpx/vp8/common/alloccommon.c b/media/libvpx/libvpx/vp8/common/alloccommon.c
index 722b158c3a..c93647fb7f 100644
--- a/media/libvpx/libvpx/vp8/common/alloccommon.c
+++ b/media/libvpx/libvpx/vp8/common/alloccommon.c
@@ -34,7 +34,7 @@ void vp8_de_alloc_frame_buffers(VP8_COMMON *oci) {
   oci->pp_limits_buffer = NULL;
 
   vpx_free(oci->postproc_state.generated_noise);
-  oci->postproc_state.generated_noise = NULL;
+  memset(&oci->postproc_state, 0, sizeof(oci->postproc_state));
 #endif
 
   vpx_free(oci->above_context);
@@ -42,10 +42,14 @@ void vp8_de_alloc_frame_buffers(VP8_COMMON *oci) {
 #if CONFIG_ERROR_CONCEALMENT
   vpx_free(oci->prev_mip);
   oci->prev_mip = NULL;
+  oci->prev_mi = NULL;
 #endif
 
   oci->above_context = NULL;
   oci->mip = NULL;
+  oci->mi = NULL;
+  oci->show_frame_mi = NULL;
+  oci->frame_to_show = NULL;
 }
 
 int vp8_alloc_frame_buffers(VP8_COMMON *oci, int width, int height) {
diff --git a/media/libvpx/reset_post_proc_state.patch b/media/libvpx/reset_post_proc_state.patch
new file mode 100644
index 0000000000..ea76e90d46
--- /dev/null
+++ b/media/libvpx/reset_post_proc_state.patch
@@ -0,0 +1,32 @@
+# HG changeset patch
+# User Jan-Ivar Bruaroey <jib@mozilla.com>
+
+Bug 2029423 - Reset post_proc state.
+
+diff --git a/vp8/common/alloccommon.c b/vp8/common/alloccommon.c
+--- a/vp8/common/alloccommon.c
++++ b/vp8/common/alloccommon.c
+@@ -34,7 +34,7 @@ void vp8_de_alloc_frame_buffers(VP8_COMM
+   oci->pp_limits_buffer = NULL;
+
+   vpx_free(oci->postproc_state.generated_noise);
+-  oci->postproc_state.generated_noise = NULL;
++  memset(&oci->postproc_state, 0, sizeof(oci->postproc_state));
+ #endif
+
+   vpx_free(oci->above_context);
+@@ -42,10 +42,14 @@ void vp8_de_alloc_frame_buffers(VP8_COMM
+ #if CONFIG_ERROR_CONCEALMENT
+   vpx_free(oci->prev_mip);
+   oci->prev_mip = NULL;
++  oci->prev_mi = NULL;
+ #endif
+
+   oci->above_context = NULL;
+   oci->mip = NULL;
++  oci->mi = NULL;
++  oci->show_frame_mi = NULL;
++  oci->frame_to_show = NULL;
+ }
+
+ int vp8_alloc_frame_buffers(VP8_COMMON *oci, int width, int height) {
\ No newline at end of file
diff --git a/media/libvpx/update.py b/media/libvpx/update.py
index 18d7166382..a673ce923d 100644
--- a/media/libvpx/update.py
+++ b/media/libvpx/update.py
@@ -46,6 +46,8 @@ def apply_patches():
     os.system("patch -p1 < vp9_svc.patch")
     # Cherrypick fix from upstream
     os.system("patch -p3 < bug1480092.patch")
+    # Bug 2029423 Resetr post_proc state
+    os.system("patch -p3 < reset_post_proc_state.patch")
 
 def update_readme(commit):
     with open('README_MOZILLA') as f: