[FFmpeg-cvslog] avformat/wtvdec: Use smaller upper bound for buffer

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Tue Sep 12 13:50:55 2023 +0200| [ea0a41bcafd17d4b97e89dd0aabc7ae08a92e780] | committer: Andreas Rheinhardt

avformat/wtvdec: Use smaller upper bound for buffer

Every code point in the BMP is representable with at most three bytes
in UTF-8 and every code point not in the BMP takes four bytes.
For each of the latter, the encoding of UTF-16 takes as many
bytes; for each of the former, it takes at most 3/2 as many.
Therefore one can decrease the size of the buffer allocated
here.

Reviewed-by: Peter Ross <pross at xvid.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ea0a41bcafd17d4b97e89dd0aabc7ae08a92e780
---

 libavformat/wtvdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
index 4ce4b6403e..9fe00590c8 100644
--- a/libavformat/wtvdec.c
+++ b/libavformat/wtvdec.c
@@ -468,7 +468,7 @@ static void get_tag(AVFormatContext *s, AVIOContext *pb, const char *key, int ty
         return;
     }
 
-    buf_size = FFMIN(FFMAX(2U * length, LEN_PRETTY_GUID) + 1, INT_MAX);
+    buf_size = FFMIN(FFMAX(length + length / 2U, LEN_PRETTY_GUID) + 1, INT_MAX);
     buf = av_malloc(buf_size);
     if (!buf)
         return;