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@gmail.com>

diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
index 81f832fe4bf41ebed676761a7bcf409ef1e4b432..46a266e12531bb27a04c812f2427cf93ce633da5 100644 (file)
--- 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);