Index: libavcodec/imgconvert.c
===================================================================
--- libavcodec/imgconvert.c	(revision 19501)
+++ libavcodec/imgconvert.c	(working copy)
@@ -688,7 +688,7 @@
         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_ARGB:
     case PIX_FMT_ABGR: