tiffenc: fix bpp value for monow/monob formats

libavcodec/tiffenc.c

@@ -282,7 +282,7 @@ static int encode_frame(AVCodecContext * avctx, unsigned char *buf,
         return -1;
     }
     if (!is_yuv)
-        s->bpp_tab_size = (s->bpp >> 3);
+        s->bpp_tab_size = ((s->bpp + 7) >> 3);
 
     if (s->compr == TIFF_DEFLATE || s->compr == TIFF_ADOBE_DEFLATE || s->compr == TIFF_LZW)
         //best choose for DEFLATE