avcodec/mpegvideo_motion: Fix off by 1 error in MV bounds checking

Fixes Ticket4299
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpegvideo_motion.c

@@ -210,8 +210,8 @@ static inline int hpel_motion(MpegEncContext *s,
         dxy |= (motion_y & 1) << 1;
     src += src_y * s->linesize + src_x;
 
-        if ((unsigned)src_x > FFMAX(s->h_edge_pos - (motion_x & 1) - 8, 0) ||
-            (unsigned)src_y > FFMAX(s->v_edge_pos - (motion_y & 1) - 8, 0)) {
+        if ((unsigned)src_x >= FFMAX(s->h_edge_pos - (motion_x & 1) - 7, 0) ||
+            (unsigned)src_y >= FFMAX(s->v_edge_pos - (motion_y & 1) - 7, 0)) {
             s->vdsp.emulated_edge_mc(s->edge_emu_buffer, src,
                                      s->linesize, s->linesize,
                                      9, 9,
@@ -306,8 +306,8 @@ void mpeg_motion_internal(MpegEncContext *s,
     ptr_cb = ref_picture[1] + uvsrc_y * uvlinesize + uvsrc_x;
     ptr_cr = ref_picture[2] + uvsrc_y * uvlinesize + uvsrc_x;
 
-    if ((unsigned)src_x > FFMAX(s->h_edge_pos - (motion_x & 1) - 16, 0) ||
-        (unsigned)src_y > FFMAX(   v_edge_pos - (motion_y & 1) - h , 0)) {
+    if ((unsigned)src_x >= FFMAX(s->h_edge_pos - (motion_x & 1) - 15   , 0) ||
+        (unsigned)src_y >= FFMAX(   v_edge_pos - (motion_y & 1) - h + 1, 0)) {
         if (is_mpeg12 ||
             s->codec_id == AV_CODEC_ID_MPEG2VIDEO ||
             s->codec_id == AV_CODEC_ID_MPEG1VIDEO) {