[FFmpeg-cvslog] eacmv: Make sure a reference frame exists before referencing it

[Martin Storsjö]

ffmpeg | branch: release/1.1 | Martin Storsjö <martin at martin.st> | Mon Sep 16 21:07:30 2013 +0300| [2e12af4587613dd5b2c3431e5c8194d73b03434f] | committer: Luca Barbato

eacmv: Make sure a reference frame exists before referencing it

This is similar to an existing check for the second-last frame
from 062421e3.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
Signed-off-by: Martin Storsjö <martin at martin.st>
(cherry picked from commit ea78a348d86a3a733f6c1e0a65cfdd8283d924b9)
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

Conflicts:
	libavcodec/eacmv.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2e12af4587613dd5b2c3431e5c8194d73b03434f
---

 libavcodec/eacmv.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavcodec/eacmv.c b/libavcodec/eacmv.c
index 0dce066..b7e13b1 100644
--- a/libavcodec/eacmv.c
+++ b/libavcodec/eacmv.c
@@ -108,9 +108,10 @@ static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *
         }else{  /* inter using last frame as reference */
             int xoffset = (buf[i] & 0xF) - 7;
             int yoffset = ((buf[i] >> 4)) - 7;
-            cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
-                      s->last_frame.data[0], s->last_frame.linesize[0],
-                      x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
+            if (s->last_frame.data[0])
+                cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
+                            s->last_frame.data[0], s->last_frame.linesize[0],
+                            x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
         }
         i++;
     }