[FFmpeg-devel] [PATCH] Shorten ID3v2 tags

James Darnley james.darnley
Sat Jul 3 01:02:50 CEST 2010


Currently an unnecessary NULL byte is written at the end of each ID3v2
tag.  The docs linked to here (
http://www.id3.org/Developer_Information ) do not say that the NULL
byte is necessary.  No other software writes this byte (lame.exe,
Winamp, mp3tag).
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>From 8b3df22c37362d4e1e3e6f5702cb61500fead975 Mon Sep 17 00:00:00 2001
From: James Darnley <james.darnley at gmail.com>
Date: Sat, 3 Jul 2010 00:27:14 +0200
Subject: [PATCH 4/5] Shorten ID3v2 tags

The strings do not need to end with a NULL byte
---
 libavformat/mp3.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavformat/mp3.c b/libavformat/mp3.c
index acb77dc..454ed22 100644
--- a/libavformat/mp3.c
+++ b/libavformat/mp3.c
@@ -321,8 +321,8 @@ static int mp3_write_header(struct AVFormatContext *s)
                 if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
                     int len = strlen(t->value);
                     tag = AV_RB32(t->key);
-                    totlen += len + ID3v2_HEADER_SIZE + 2;
-                    id3v2_put_ttag(s, t->value, len + 1, tag);
+                    totlen += len + ID3v2_HEADER_SIZE + 1;
+                    id3v2_put_ttag(s, t->value, len, tag);
                     break;
                 }
         }
@@ -335,8 +335,8 @@ static int mp3_write_header(struct AVFormatContext *s)
             tag = MKBETAG('T', 'X', 'X', 'X');
             strcpy(buf,           t->key);
             strcpy(buf + len + 1, t->value);
-            id3v2_put_ttag(s, buf, len + len1 + 2, tag);
-            totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
+            id3v2_put_ttag(s, buf, len + len1 + 1, tag);
+            totlen += len + len1 + ID3v2_HEADER_SIZE + 2;
             av_free(buf);
         }
     }
-- 
1.7.0.4



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