[FFmpeg-cvslog] mp3enc: avoid truncating id3v1 tags by one byte

[Tobias Rapp]

ffmpeg | branch: release/0.7 | Tobias Rapp <t.rapp at noa-audio.com> | Mon Oct 31 15:11:37 2011 +0100| [d8acee792f9d3b2c271d480e4d72ff7e558e0c66] | committer: Michael Niedermayer

mp3enc: avoid truncating id3v1 tags by one byte

Avoid writing the trailing null-byte for id3v1 tags if length reaches max length.

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 0f39fa0279e12c7a174d1da9294bffd95cb15c4c)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d8acee792f9d3b2c271d480e4d72ff7e558e0c66
---

 libavformat/mp3enc.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c
index 50342bb..76d1813 100644
--- a/libavformat/mp3enc.c
+++ b/libavformat/mp3enc.c
@@ -51,11 +51,12 @@ static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
     buf[0] = 'T';
     buf[1] = 'A';
     buf[2] = 'G';
-    count += id3v1_set_string(s, "TIT2",    buf +  3, 30);       //title
-    count += id3v1_set_string(s, "TPE1",    buf + 33, 30);       //author|artist
-    count += id3v1_set_string(s, "TALB",    buf + 63, 30);       //album
-    count += id3v1_set_string(s, "TDRL",    buf + 93,  4);       //date
-    count += id3v1_set_string(s, "comment", buf + 97, 30);
+    /* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
+    count += id3v1_set_string(s, "TIT2",    buf +  3, 30 + 1);       //title
+    count += id3v1_set_string(s, "TPE1",    buf + 33, 30 + 1);       //author|artist
+    count += id3v1_set_string(s, "TALB",    buf + 63, 30 + 1);       //album
+    count += id3v1_set_string(s, "TDRL",    buf + 93,  4 + 1);       //date
+    count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);
     if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
         buf[125] = 0;
         buf[126] = atoi(tag->value);