[FFmpeg-cvslog] avcodec/mpegvideo_enc: Don't apply non-zero offset to null pointer

[Andreas Rheinhardt]

ffmpeg | branch: release/4.4 | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Fri Mar 26 07:15:56 2021 +0100| [09510d9ffd91d1b734d8099884dfb916069b4f2e] | committer: Andreas Rheinhardt

avcodec/mpegvideo_enc: Don't apply non-zero offset to null pointer

Affected many FATE tests (mostly vsynth ones).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
(cherry picked from commit 4863671d888273392e9dcc2429f3852c00330498)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=09510d9ffd91d1b734d8099884dfb916069b4f2e
---

 libavcodec/mpegvideo_enc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
index 7eecfce27c..a095062052 100644
--- a/libavcodec/mpegvideo_enc.c
+++ b/libavcodec/mpegvideo_enc.c
@@ -1696,7 +1696,8 @@ no_output_pic:
             // input is not a shared pix -> reuse buffer for current_pix
             s->current_picture_ptr = s->reordered_input_picture[0];
             for (i = 0; i < 4; i++) {
-                s->new_picture.f->data[i] += INPLACE_OFFSET;
+                if (s->new_picture.f->data[i])
+                    s->new_picture.f->data[i] += INPLACE_OFFSET;
             }
         }
         ff_mpeg_unref_picture(s->avctx, &s->current_picture);