100l in avpicture_layout: width of chroma planes depends on format depth, too.

Fixes issue 1465

Originally committed as revision 20202 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/imgconvert.c

@@ -897,7 +897,7 @@ int avpicture_layout(const AVPicture* src, enum PixelFormat pix_fmt, int width,
 
     for (i=0; i<data_planes; i++) {
          if (i == 1) {
-             w = width >> pf->x_chroma_shift;
+             w = ((width >> pf->x_chroma_shift) * pf->depth + 7) / 8;
              h = height >> pf->y_chroma_shift;
          } else if (i == 3) {
              w = ow;