diff -urw x264-snapshot-20080423-2245.orig/common/frame.c x264-snapshot-20080423-2245/common/frame.c
--- x264-snapshot-20080423-2245.orig/common/frame.c	Wed Apr 23 21:45:06 2008
+++ x264-snapshot-20080423-2245/common/frame.c	Thu Apr 24 04:42:03 2008
@@ -120,17 +120,19 @@
         for( j = 0; j < h->param.i_bframe + 2; j++ )
             CHECKED_MALLOC( frame->i_row_satds[i][j], i_lines/16 * sizeof(int) );
 
+    if( h->param.i_threads > 1 ) {
     x264_pthread_mutex_init( &frame->mutex, NULL );
     x264_pthread_cond_init( &frame->cv, NULL );
+    }
 
     return frame;
 
 fail:
-    x264_frame_delete( frame );
+    x264_frame_delete( h, frame );
     return NULL;
 }
 
-void x264_frame_delete( x264_frame_t *frame )
+void x264_frame_delete( x264_t *h, x264_frame_t *frame )
 {
     int i, j;
     for( i = 0; i < 4; i++ )
@@ -147,8 +149,10 @@
     x264_free( frame->mv[1] );
     x264_free( frame->ref[0] );
     x264_free( frame->ref[1] );
+    if( h->param.i_threads > 1 ) {
     x264_pthread_mutex_destroy( &frame->mutex );
     x264_pthread_cond_destroy( &frame->cv );
+    }
     x264_free( frame );
 }
 
diff -urw x264-snapshot-20080423-2245.orig/common/frame.h x264-snapshot-20080423-2245/common/frame.h
--- x264-snapshot-20080423-2245.orig/common/frame.h	Wed Apr 23 21:45:06 2008
+++ x264-snapshot-20080423-2245/common/frame.h	Thu Apr 24 04:31:14 2008
@@ -101,7 +101,7 @@
 } x264_deblock_function_t;
 
 x264_frame_t *x264_frame_new( x264_t *h );
-void          x264_frame_delete( x264_frame_t *frame );
+void          x264_frame_delete( x264_t *h, x264_frame_t *frame );
 
 int           x264_frame_copy_picture( x264_t *h, x264_frame_t *dst, x264_picture_t *src );
 
diff -urw x264-snapshot-20080423-2245.orig/encoder/encoder.c x264-snapshot-20080423-2245/encoder/encoder.c
--- x264-snapshot-20080423-2245.orig/encoder/encoder.c	Wed Apr 23 21:45:06 2008
+++ x264-snapshot-20080423-2245/encoder/encoder.c	Thu Apr 24 04:31:58 2008
@@ -1940,13 +1940,13 @@
 
     /* frames */
     for( i = 0; h->frames.current[i]; i++ )
-        x264_frame_delete( h->frames.current[i] );
+        x264_frame_delete( h, h->frames.current[i] );
     for( i = 0; h->frames.next[i]; i++ )
-        x264_frame_delete( h->frames.next[i] );
+        x264_frame_delete( h, h->frames.next[i] );
     for( i = 0; h->frames.unused[i]; i++ )
-        x264_frame_delete( h->frames.unused[i] );
+        x264_frame_delete( h, h->frames.unused[i] );
     for( i = 0; h->frames.reference[i]; i++ )
-        x264_frame_delete( h->frames.reference[i] );
+        x264_frame_delete( h, h->frames.reference[i] );
 
     /* rc */
     x264_ratecontrol_delete( h );