[FFmpeg-cvslog] dvbsubdec: fix division by zero in compute_default_clut

[Andreas Cadhalpun]

ffmpeg | branch: release/3.0 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Tue Nov  8 22:32:42 2016 +0100| [27888d13b8d370b365593312d6755d268a4428f6] | committer: Andreas Cadhalpun

dvbsubdec: fix division by zero in compute_default_clut

This problem was introduced in commit
4b90dcb8493552c17a811c8b1e6538dae4061f9d.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
(cherry picked from commit c82b8ef0e4f226423ddd644bfe37e6a15d070924)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=27888d13b8d370b365593312d6755d268a4428f6
---

 libavcodec/dvbsubdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/dvbsubdec.c b/libavcodec/dvbsubdec.c
index a4663d9..08f6a9b 100644
--- a/libavcodec/dvbsubdec.c
+++ b/libavcodec/dvbsubdec.c
@@ -810,7 +810,7 @@ static void compute_default_clut(AVSubtitleRect *rect, int w, int h)
         list_inv[     i ] = bestv;
     }
 
-    count = i - 1;
+    count = FFMAX(i - 1, 1);
     for (i--; i>=0; i--) {
         int v = i*255/count;
         AV_WN32(rect->data[1] + 4*list_inv[i], RGBA(v/2,v,v/2,v));