#id3v2lib

id3v2lib is a library written in C to read and edit id3 tags from mp3 files. It is focused on the ease of use. As it is a personal project, the software is provided "as is" without warranty of any kind.

It is licensed under BSD License. See LICENSE for details.

It is a work in progress so some functionality is not implemented yet.

##What it can do?

id3v2lib can read and edit id3 v2.3 and v2.4 tags from mp3 files. It can read and edit a small subset of tags by default. Specifically, the most used tags:

• Title
• Album
• Artist
• Album Artist
• Comment
• Year
• Track
• Album Number
• Album Cover

However, it can be extended, in a very easy manner, to read other id3 tags.

Building id3v2lib

Building using CMake

The id3v2lib library is built using CMake 2.6+ on all platforms. On most systems you can build and install the library using the following commands:

$ mkdir build && cd build
$ cmake .. 
$ make && make install

Most of the times, you need to run the make install command with su privileges.

Building using Microsoft Visual Studio

Microsoft Visual Studio needs a slightly different way of building. Open the Visual Studio Developers Console, ch into the id3v2lib folder and execute the following:

$ mkdir build && cd build
$ cmake ..

This should leave you with several MSVS projects in the \build directory. Open ALL_BUILD.vcxproj with Visual Studio and build it as usual. The resulting lib file can be found in \build\src\Debug\id3v2.lib

Usage

You only have to include the main header of the library:

#include <id3v2lib.h>
	
int main(int argc, char* argv[])
{
	// Etc..
}

And when compiling, link against the static library:

$ gcc -o example example.c -lid3v2

Main functions

File functions

This functions interacts directly with the file to edit. This functions are:

• ID3v2_tag* load_tag(const char* filename)
• void remove_tag(const char* filename)
• void set_tag(const char* filename, ID3v2_tag* tag)

Tag functions

This functions interacts with the tags in the file. They are classified in three groups:

Getter functions

Retrieve information from a tag, they have the following name pattern:

• tag_get_[frame] where frame is the name of the desired field from which to obtain information. It can be one of the previously mentioned tags.

Setter functions

Set the information of a field, they have the following name pattern:

• tag_set_[frame] where frame is the name of the desired field to edit. It can be one of the previously mentioned tags.

Delete functions

Delete individual fields in the tag, they have the following name pattern:

• tag_delete_[frame] where frame is the name of the desired field to delete. It can be one of the previously mentioned tags.

Examples

Load tags

ID3v2_tag* tag = load_tag("file.mp3"); // Load the full tag from the file
if(tag == NULL)
{
	tag = new_tag();
}
	
// Load the fields from the tag
ID3v2_frame* artist_frame = tag_get_artist(tag); // Get the full artist frame
// We need to parse the frame content to make readable
ID3v2_frame_text_content* artist_content = parse_text_frame_content(artist_frame); 
printf("ARTIST: %s\n", artist_content->data); // Show the artist info
	
ID3v2_frame* title_frame = tag_get_title(tag);
ID3v2_frame_text_content* title_content = parse_text_frame_content(title_frame);
printf("TITLE: %s\n", title_content->data);

Edit tags

ID3v2_tag* tag = load_tag("file.mp3"); // Load the full tag from the file
if(tag == NULL)
{
	tag = new_tag();
}

// Set the new info
tag_set_title("Title", 0, tag);
tag_set_artist("Artist", 0, tag);

// Write the new tag to the file
set_tag("file.mp3", tag);

Delete tags

ID3v2_tag* tag = load_tag("file.mp3"); // Load the full tag from the file
if(tag == NULL)
{
	tag = new_tag();
}

// We can delete single frames
tag_delete_title(tag);
tag_delete_artist(tag);

// Write the new tag to the file
set_tag("file.mp3", tag);

// Or we can delete the full tag
remove_tag("file.mp3")

Extending functionality

Read new frames

Suppose we want to read the frame that stores the copyright message (TCOP). We have to do the following:

ID3v2_tag* tag = load_tag("file.mp3"); // Load the full tag from the file
if(tag == NULL)
{
	tag = new_tag();
}

ID3v2_frame* copyright_frame = tag_get_frame(tag, "TCOP"); // Get the copyright message frame
// We need to parse the frame content to make it readable, as the copyright message is a text frame,
// we use the parse_text_frame_content function.
ID3v2_frame_text_content* copyright_content = parse_text_frame_content(copyright_frame); 
printf("COPYRIGHT: %s\n", copyright_content->data); // Show the copyright info

Edit new frames

Suppose that now, we want to edit the copyright frame. We have to do the following:

ID3v2_tag* tag = load_tag("file.mp3"); // Load the full tag from the file
if(tag == NULL)
{
	tag = new_tag();
}

ID3v2_frame* copyright_frame = NULL;
if( ! (copyright_frame = tag_get_frame(tag, "TCOP")))
{
    copyright_frame = new_frame();
    add_to_list(tag->frames, copyright_frame);
}

set_text_frame("A copyright message", 0, "TCOP", copyright_frame);

Copyright

Copyright (c) 2013 Lorenzo Ruiz. See LICENSE for details.

Questions?

If you have any questions, please feel free to ask me. I will try to answer it ASAP.