[FFmpeg-devel] [PATCH] Fix ID3v1 tags in mp3 files

[James Darnley]

When writing mp3 files, the metadata keys get converted to the ID3v2
tags.  So if one tries to get a tag based on its generic name, the tag
won't be found, meaning that the ID3v1 comment will be filled with a
load of null bytes.

This patch changes what keys are searched for.  Is it correct that the
conversion into format specific keys always uses the first matching
AVMetadataConv?  Specifically, will "album" always become "TALB" with
the following?
    { "TALB", "album"},
    { "TAL",  "album"},
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>From cb61a1ec733af1cd12a549816237bfe4abc5c3dc Mon Sep 17 00:00:00 2001
From: James Darnley <james.darnley at gmail.com>
Date: Wed, 23 Jun 2010 21:32:43 +0200
Subject: [PATCH 3/5] Fix ID3v1 tags

The tag keys have been converted to the ID3v2 format so one must find them using those keys
---
 libavformat/mp3.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libavformat/mp3.c b/libavformat/mp3.c
index bdb2e4e..acb77dc 100644
--- a/libavformat/mp3.c
+++ b/libavformat/mp3.c
@@ -214,18 +214,18 @@ static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
     buf[0] = 'T';
     buf[1] = 'A';
     buf[2] = 'G';
-    count += id3v1_set_string(s, "title",   buf +  3, 30);
-    count += id3v1_set_string(s, "author",  buf + 33, 30);
-    count += id3v1_set_string(s, "album",   buf + 63, 30);
-    count += id3v1_set_string(s, "date",    buf + 93,  4);
+    count += id3v1_set_string(s, "TIT2",    buf +  3, 30);       //title
+    count += id3v1_set_string(s, "TPE1",    buf + 33, 30);       //author
+    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);
-    if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
+    if ((tag = av_metadata_get(s->metadata, "TRCK", NULL, 0))) { //track
         buf[125] = 0;
         buf[126] = atoi(tag->value);
         count++;
     }
     buf[127] = 0xFF; /* default to unknown genre */
-    if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
+    if ((tag = av_metadata_get(s->metadata, "TCON", NULL, 0))) { //genre
         for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
             if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
                 buf[127] = i;
-- 
1.7.0.4