David Cumps

Sync FLAC Library with iPod

Originally published on my old blog at cumps.be on August 11, 2007.

Yesterday I explained how you could manage your iPod through Windows Explorer. Having this ability opens up more powerful ways of managing your iPod. One of these ways for example is the ability to automatically sync your master archive stored on your computer, with your iPod. In my case it’s stored in FLAC format to retain all it’s quality, since FLAC is a lossless format.

Armed with TagLib#, LAME, FLAC and a nice Scan directories using recursion to recursively search through a directory for files, I slapped together a small synchronization application for myself.

On my iPod I have the following batch file, EncodeLibrary.bat, stored:

@ECHO OFF
ECHO Running: '%~d0\LibrarySync.exe %~d0\ C:\Media\Music %~d0\Music'
ECHO Encodes to MP3 with: -V 4 --vbr-new
%~d0\LibrarySync.exe %~d0\ C:\Media\Music %~d0\Music
ECHO Done.

This file simply calls my utility, LibrarySync.exe, and passes in the drive it is running on (%~d0), The Archive and the target directory. In my application I then simply scan for all available FLAC files, through a wildcard search, in the archive and trigger an action whenever a file is found.

static void Main(string[] args)
{
    /* Note to blog reader: These used to be constants, never properly refactored it since it was a quick and dirty personal app. */
    DRIVE = args[0];
    FROMDIR = args[1];
    TODIR = args[2];

    ScanDirectory scanDirectory = new ScanDirectory();

    scanDirectory.FileEvent += new ScanDirectory.FileEventHandler(scanDirectory_FileEvent);
    scanDirectory.SearchPattern = "*.flac";

    scanDirectory.WalkDirectory(FROMDIR);
}

Whenever a FLAC file is found, I check if the target MP3 already exists, and in case it doesn’t exist yet, I call a Convert.bat file. I’ve chosen to use an external batch file to handle the copying, this way I can simply open it up in a text editor and change the encoding quality or the paths to the encoder.

After encoding the file, I take the meta data from the original FLAC file and place it in the target MP3 ID3v1 and ID3v2 tags. This way my iPod can read out the file details and organize it easily in it’s catalog.

static void scanDirectory_FileEvent(object sender, FileEventArgs e)
{
    string from = e.Info.FullName;
    string to = TODIR + e.Info.FullName.Remove(0, FROMDIR.Length).Replace(".flac", ".mp3");
    string toDir = TODIR + e.Info.DirectoryName.Remove(0, FROMDIR.Length);

    if (!IO.File.Exists(to))
    {
        if (!IO.Directory.Exists(toDir))
        {
            IO.Directory.CreateDirectory(toDir);
        }

        Console.WriteLine("Writing " + to);

        Process convertFile = new Process();
        convertFile.StartInfo.UseShellExecute = false;
        convertFile.StartInfo.RedirectStandardOutput = false;

        convertFile.StartInfo.FileName = DRIVE + "Convert.bat";
        convertFile.StartInfo.Arguments = "\"" + from + "\" \"" + to + "\"";
        convertFile.Start();

        convertFile.WaitForExit();

        Flac.File flacFile = new Flac.File(from);
        TagLib.Tag flacTag = flacFile.GetTag(TagLib.TagTypes.FlacMetadata, false);

        TagLib.File mp3File = TagLib.File.Create(to);
        MP3.Tag mp3Tag = mp3File.GetTag(TagLib.TagTypes.Id3v2) as TagLib.Id3v2.Tag;
        MP3Old.Tag mp3OldTag = mp3File.GetTag(TagLib.TagTypes.Id3v1) as TagLib.Id3v1.Tag;

        if (flacTag.Album != null) {            mp3Tag.Album = flacTag.Album;                                       }
        if (flacTag.FirstPerformer != null) {   mp3Tag.Performers = new string [] { flacTag.FirstPerformer };       }
        if (flacTag.Title != null) {            mp3Tag.Title = flacTag.Title;                                       }
        if (flacTag.Year != 0) {                mp3Tag.Year = flacTag.Year;                                         }
        if (flacTag.FirstGenre != null) {       mp3Tag.Genres = new string [] { flacTag.FirstGenre };               }
        if (flacTag.Track != 0) {               mp3Tag.Track = flacTag.Track;                                       }

        if (flacTag.Album != null) {            mp3OldTag.Album = flacTag.Album;                                    }
        if (flacTag.FirstPerformer != null) {   mp3OldTag.Performers = new string [] { flacTag.FirstPerformer };    }
        if (flacTag.Title != null) {            mp3OldTag.Title = flacTag.Title;                                    }
        if (flacTag.Year != 0) {                mp3OldTag.Year = flacTag.Year;                                      }
        if (flacTag.FirstGenre != null) {       mp3OldTag.Genres = new string [] { flacTag.FirstGenre };            }
        if (flacTag.Track != 0) {               mp3OldTag.Track = flacTag.Track;                                    }

        mp3File.Save();

        Console.WriteLine();
    }
}

The content of my Convert.bat file looks like this:

@ECHO OFF
"%~d0\Tools\FLAC\flac.exe" --decode --stdout --silent %1 | "%~d0\Tools\LAME\latest\lame.exe" -V 4 --vbr-new - %2

It simply encodes the FLAC file to a VBR MP3 with a target bitrate of 165kbps.

All said and done, this is how the tool looks like in action:

Encoding FLAC files to MP3

When I connect my iPod, I usually follow these steps from now on:

  • Run **reTune** to manage my songs in Windows Explorer.
  • Run **EncodeLibrary** to encode possible missing songs.
  • Run **reTune** to organize them back into my iPod.
  • Disconnect and **listen to music**.
I created [a small zip file](librarysync.zip) for anyone who would like to set something like this up for himself as well. To use it, simply follow the following steps:
  • Extract the zip file to the **root** of your iPod.
  • Edit **EncodeLibrary.bat** to point to your master archive, and the target folder.
  • Get the [FLAC](http://flac.sourceforge.net/download.html "FLAC Download") and [LAME](http://www.rarewares.org/mp3-lame-bundle.php "LAME Download") files and place them in a folder called **Tools**. Look at **Convert.bat** to determine the exact paths.
  • Run **EncodeLibrary.bat** from a command prompt, and with a bit of luck it'll work for you. If not, **leave a comment** and I'll see what I can do for you.
Do you know of other cool things I could create for my iPod? **Comment** and let me know!
About Me David Cumps

My name is

David Cumps

Freelance polyglot software engineer

A passionate geek, always curious, always learning.
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