diff --git a/autogen.sh b/autogen.sh
index 2a2e364ce9..8a096a0276 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -18,18 +18,28 @@ git submodule update
 
 if test -x $have_svn && [ $have_svn ];
 then
-    if test ! -f $FFMPEG_CO_DIR/configure
-    then
+    co_ffmpeg=no
+
+    if test ! -f $FFMPEG_CO_DIR/configure; then
+      co_ffmpeg=yes
+    else
+      if ! svn info gst-libs/ext/ffmpeg | grep "URL: $FFMPEG_SVN" > /dev/null; then
+        echo "FFmpeg checkout is on the wrong branch. Re-fetching."
+        co_ffmpeg=yes
+      fi
+    fi
+
+    if [ "$co_ffmpeg" = "yes" ]; then
 	# checkout ffmpeg from its repository
 	rm -rf $FFMPEG_CO_DIR
 	echo "+ getting ffmpeg from svn"
 	svn -r $FFMPEG_REVISION co $FFMPEG_SVN $FFMPEG_CO_DIR
-	echo "+ updating externals"
-	svn update -r $FFMPEG_EXTERNALS_REVISION $FFMPEG_CO_DIR/libswscale
     else
 	# update ffmpeg from its repository
 	echo "+ updating ffmpeg checkout"
 	svn -r $FFMPEG_REVISION up $FFMPEG_CO_DIR
+    fi
+    if [ "x$FFMPEG_EXTERNALS_REVISION" != "x" ]; then
 	echo "+ updating externals"
 	svn update -r $FFMPEG_EXTERNALS_REVISION $FFMPEG_CO_DIR/libswscale
     fi
diff --git a/ffmpegrev b/ffmpegrev
index f1ad70b50d..4d2f8cd2d9 100644
--- a/ffmpegrev
+++ b/ffmpegrev
@@ -1,8 +1,9 @@
 FFMPEG_REVISION=18939
 FFMPEG_CO_DIR=gst-libs/ext/ffmpeg
 FFMPEG_SVN=svn://svn.ffmpeg.org/ffmpeg/branches/0.5
-# Because ffmpeg checks out libswscale via an svn:externals, checking
+# Because ffmpeg trunk checks out libswscale via an svn:externals, checking
 # out an old ffmpeg does not check out a corresponding libswscale.
 # Keep the swscale checkout manually synchronized, then. Update this
-# when you update FFMPEG_REVISION.
-FFMPEG_EXTERNALS_REVISION=29320
+# when you update FFMPEG_REVISION. Set it to empty if there's no
+# external to update (as on ffmpeg 0.5 branch)
+FFMPEG_EXTERNALS_REVISION=
diff --git a/gst-libs/ext/Makefile.am b/gst-libs/ext/Makefile.am
index cbafe3ac7a..d11bc963d4 100644
--- a/gst-libs/ext/Makefile.am
+++ b/gst-libs/ext/Makefile.am
@@ -29,7 +29,9 @@ distclean: dist-clean
 
 dist-local:
 	svn -r $(FFMPEG_REVISION) co $(FFMPEG_SVN) $(TMP_DIST_DIR)
-	svn update -r $(FFMPEG_EXTERNALS_REVISION) $(TMP_DIST_DIR)/libswscale
+	@if [ "x$(FFMPEG_EXTERNALS_REVISION)" != x ]; then \
+		svn update -r $(FFMPEG_EXTERNALS_REVISION) $(TMP_DIST_DIR)/libswscale; \
+	fi
 	mkdir $(DIST_DIR)
 	pwd
 	cp $(TMP_DIST_DIR)/*.c $(TMP_DIST_DIR)/*.h $(TMP_DIST_DIR)/Makefile $(TMP_DIST_DIR)/configure $(TMP_DIST_DIR)/version.sh $(DIST_DIR)