diff -ur mlt-0.5.4/src/modules/sdl/consumer_sdl.c mlt-0.5.4-patched/src/modules/sdl/consumer_sdl.c
--- mlt-0.5.4/src/modules/sdl/consumer_sdl.c	2010-04-20 07:32:40.000000000 +0300
+++ mlt-0.5.4-patched/src/modules/sdl/consumer_sdl.c	2010-09-28 21:51:14.000000000 +0300
@@ -1,6 +1,6 @@
 /*
  * consumer_sdl.c -- A Simple DirectMedia Layer consumer
- * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
+ * Copyright (C) 2003-2004, 2010 Ushodaya Enterprises Limited
  * Author: Dan Dennedy <dan@dennedy.org>
  *
  * This library is free software; you can redistribute it and/or
@@ -187,7 +187,10 @@
 
 		if ( sdl_started == 0 && display_off == 0 )
 		{
-			if ( SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE ) < 0 )
+			pthread_mutex_lock( &mlt_sdl_mutex );
+			int ret = SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE );
+			pthread_mutex_unlock( &mlt_sdl_mutex );
+			if ( ret < 0 )
 			{
 				mlt_log_error( MLT_CONSUMER_SERVICE(parent), "Failed to initialize SDL: %s\n", SDL_GetError() );
 				return -1;
@@ -198,7 +201,9 @@
 		}
 		else if ( display_off == 0 )
 		{
+			pthread_mutex_lock( &mlt_sdl_mutex );
 			this->sdl_screen = SDL_GetVideoSurface( );
+			pthread_mutex_unlock( &mlt_sdl_mutex );
 		}
 
 		if ( audio_off == 0 )
@@ -213,7 +218,10 @@
 		{
 			if ( mlt_properties_get_int( this->properties, "fullscreen" ) )
 			{
-				const SDL_VideoInfo *vi = SDL_GetVideoInfo();
+				const SDL_VideoInfo *vi;
+				pthread_mutex_lock( &mlt_sdl_mutex );
+				vi = SDL_GetVideoInfo();
+				pthread_mutex_unlock( &mlt_sdl_mutex );
 				this->window_width = vi->current_w;
 				this->window_height = vi->current_h;
 				this->sdl_flags |= SDL_FULLSCREEN;
diff -ur mlt-0.5.4/src/modules/sdl/consumer_sdl_audio.c mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_audio.c
--- mlt-0.5.4/src/modules/sdl/consumer_sdl_audio.c	2010-04-20 07:32:40.000000000 +0300
+++ mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_audio.c	2010-09-28 21:51:14.000000000 +0300
@@ -1,6 +1,6 @@
 /*
  * consumer_sdl_audio.c -- A Simple DirectMedia Layer audio-only consumer
- * Copyright (C) 2009 Ushodaya Enterprises Limited
+ * Copyright (C) 2009, 2010 Ushodaya Enterprises Limited
  * Author: Dan Dennedy <dan@dennedy.org>
  *
  * This library is free software; you can redistribute it and/or
@@ -31,6 +31,8 @@
 #include <SDL/SDL.h>
 #include <sys/time.h>
 
+extern pthread_mutex_t mlt_sdl_mutex;
+
 /** This classes definition.
 */
 
@@ -158,7 +160,11 @@
 		this->running = 1;
 		this->joined = 0;
 
-		if ( SDL_Init( SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE ) < 0 )
+
+		pthread_mutex_lock( &mlt_sdl_mutex );
+		int ret = SDL_Init( SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE );
+		pthread_mutex_unlock( &mlt_sdl_mutex );
+		if ( ret < 0 )
 		{
 			mlt_log_error( MLT_CONSUMER_SERVICE(parent), "Failed to initialize SDL: %s\n", SDL_GetError() );
 			return -1;
diff -ur mlt-0.5.4/src/modules/sdl/consumer_sdl_preview.c mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_preview.c
--- mlt-0.5.4/src/modules/sdl/consumer_sdl_preview.c	2010-04-20 07:32:40.000000000 +0300
+++ mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_preview.c	2010-09-28 21:51:14.000000000 +0300
@@ -1,6 +1,6 @@
 /*
  * consumer_sdl_preview.c -- A Simple DirectMedia Layer consumer
- * Copyright (C) 2004-2005 Ushodaya Enterprises Limited
+ * Copyright (C) 2004-2005, 2010 Ushodaya Enterprises Limited
  * Author: Charles Yates
  *
  * This library is free software; you can redistribute it and/or
@@ -174,7 +174,10 @@
 		if ( audio_device != NULL )
 			setenv( "AUDIODEV", audio_device, 1 );
 
-		if ( SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE ) < 0 )
+		pthread_mutex_lock( &mlt_sdl_mutex );
+		int ret = SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE );
+		pthread_mutex_unlock( &mlt_sdl_mutex );
+		if ( ret < 0 )
 		{
 			fprintf( stderr, "Failed to initialize SDL: %s\n", SDL_GetError() );
 			return -1;
diff -ur mlt-0.5.4/src/modules/sdl/consumer_sdl_still.c mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_still.c
--- mlt-0.5.4/src/modules/sdl/consumer_sdl_still.c	2010-04-20 07:32:40.000000000 +0300
+++ mlt-0.5.4-patched/src/modules/sdl/consumer_sdl_still.c	2010-09-28 21:51:14.000000000 +0300
@@ -1,6 +1,6 @@
 /*
  * consumer_sdl_still.c -- A Simple DirectMedia Layer consumer
- * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
+ * Copyright (C) 2003-2004, 2010 Ushodaya Enterprises Limited
  * Author: Charles Yates
  *
  * This library is free software; you can redistribute it and/or
@@ -167,7 +167,10 @@
 
 		if ( sdl_started == 0 && preview_off == 0 )
 		{
-			if ( SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE ) < 0 )
+			pthread_mutex_lock( &mlt_sdl_mutex );
+			int ret = SDL_Init( SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE );
+			pthread_mutex_unlock( &mlt_sdl_mutex );
+			if ( ret < 0 )
 			{
 				fprintf( stderr, "Failed to initialize SDL: %s\n", SDL_GetError() );
 				return -1;
@@ -178,9 +181,12 @@
 		}
 		else if ( preview_off == 0 )
 		{
-			if ( SDL_GetVideoSurface( ) != NULL )
+			pthread_mutex_lock( &mlt_sdl_mutex );
+			SDL_Surface *screen = SDL_GetVideoSurface( );
+			pthread_mutex_unlock( &mlt_sdl_mutex );
+			if ( screen != NULL )
 			{
-				this->sdl_screen = SDL_GetVideoSurface( );
+				this->sdl_screen = screen;
 			}
 		}
 
@@ -439,10 +445,10 @@
 		this->sdl_screen = SDL_SetVideoMode( this->window_width, this->window_height, 0, this->sdl_flags );
 		if ( consumer_get_dimensions( &this->window_width, &this->window_height ) )
 			this->sdl_screen = SDL_SetVideoMode( this->window_width, this->window_height, 0, this->sdl_flags );
-		pthread_mutex_unlock( &mlt_sdl_mutex );
 
 		uint32_t color = mlt_properties_get_int( this->properties, "window_background" );
 		SDL_FillRect( this->sdl_screen, NULL, color >> 8 );
+		pthread_mutex_unlock( &mlt_sdl_mutex );
 		changed = 1;
 	}
 
@@ -501,7 +507,10 @@
 		mlt_properties_set_int( this->properties, "rect_h", this->rect.h );
 	}
 	
-	if ( !mlt_consumer_is_stopped( &this->parent ) && SDL_GetVideoSurface( ) != NULL && this->sdl_screen != NULL && this->sdl_screen->pixels != NULL )
+	pthread_mutex_lock( &mlt_sdl_mutex );
+	SDL_Surface *screen = SDL_GetVideoSurface( );
+	pthread_mutex_unlock( &mlt_sdl_mutex );
+	if ( !mlt_consumer_is_stopped( &this->parent ) && screen != NULL && this->sdl_screen != NULL && this->sdl_screen->pixels != NULL )
 	{
 		switch( this->sdl_screen->format->BytesPerPixel )
 		{