Index: libavcodec/imgconvert.c
===================================================================
--- 1/libavcodec/imgconvert.c	(revision 13659)
+++ 2/libavcodec/imgconvert.c	(working copy)
@@ -466,7 +466,7 @@
         break;
     case PIX_FMT_RGB24:
     case PIX_FMT_BGR24:
-        picture->linesize[0] = width * 3;
+        picture->linesize[0] = (width * 3 + 3) & ~3;
         break;
     case PIX_FMT_RGB32:
     case PIX_FMT_BGR32: