Fix deinterlacing for odd height

Originally committed as revision 9942 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/xsubdec.c

@@ -84,7 +84,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     bitmap = sub->rects[0].bitmap;
     for (y = 0; y < h; y++) {
         // interlaced: do odd lines
-        if (y == h / 2) bitmap = sub->rects[0].bitmap + w;
+        if (y == (h + 1) / 2) bitmap = sub->rects[0].bitmap + w;
         for (x = 0; x < w; ) {
             int log2 = ff_log2_tab[show_bits(&gb, 8)];
             int run = get_bits(&gb, 14 - 4 * (log2 >> 1));