PACPL, the Perl Audio Converter, is a great Perl script that will batch transcode audio files from one format to another. For a variety of reasons, my music library is in the WMA Lossless format, and I wanted to use PACPL to transcode the WMA files to MP3. By default, PACPL does not support transcoding of WMA Lossless files, so I patched the script to add the support. While I was under the hood, I added support for the “Composer” and “Album Artist” meta tags for WMA decoding and MP3 encoding. The Album Artist tag helps media players like iTunes group songs by album, even if there are different performers. I also added support for embedding album art into MP3 files.
PACPL normally uses ffmpeg to decode WMA files, but ffmpeg does not support WMA Lossless. With the patch, PACPL has the option to use mplayer to decode WMA files. This works fine, with one exception. Some versions of mplayer (like the one I use: 1.0rc1-4.1.2) have a bug that prevents it from properly creating files with commas in the filename or path. I added options to remove commas from decoded filenames and to use the /tmp directory for decoding. Edit the script and set both options to 1 if you have problems with mplayer.
# decoding options for temp files
# use /tmp/ directory for temporary decoded .wav files
my $decode_usetmp = 0;
# replace commas in decode filename to work around mplayer bug
my $decode_replacecommas = 0;For embedded album art, I added a command line option --albumart= to specify the source album art JPG file name. It expects a JPG file that is in the same directory as the source audio files. If it finds the JPG, it will embed the image into the MP3 header. I did not add album art support to any other output formats, though it should be easy enough to do if their Perl modules support it.
I ended up learning more about the MP3 ID3 metadata format than I intended. What a mess. Fortunately, the MP3::Tag module is pretty robust. That said, I did find a bug. The test file I used was a Stevie Ray Vaughan song, which has the genre “Blues.” This is the first genre in the ID3 genre list, and has the ID of 0. For the life of me, I couldn’t figure out why the script was losing the genre tag until I realized that a genre ID of 0 was getting skipped by MP3::Tag. I added a workaround to change the Blues genre name to be “Blues & Roots”, which forces the genre to be encoded as a string instead of ID number.
I also found that different media players treat album art in different ways. That is, some players are very forgiving of bad metadata headers, while others are not. I tested album art in iTunes, Foobar 2000, Windows Media Player, VLC, Winamp, and Amarok. For reference, here’s the magic header for JPG album art that works with all of the tested media players:
# important to set unsync to false, otherwise ID3v2 data can appear "corrupt"
MP3::Tag->config("id3v23_unsync_size_w",0);
MP3::Tag->config("id3v23_unsync",0);
$tag_m = MP3::Tag->new("$out_file");
# ID3v2 Tags
unless(exists($tag_m->{ID3v2})) { $tag_m->new_tag("ID3v2"); }
$tag_m->{ID3v2}->add_frame("APIC", "\x00", "image/jpeg", "\x03", "Cover (front)", $imagedata);With my patches, here’s the shell command I use for transcoding a directory tree of WMA Lossless files to high-bitrate mp3 files:
pacpl -v -t mp3 -r -p -o wma --albumart="Folder.jpg" --defopts 0 --eopts="-q 0 -v -V 0 -b 320 -F" --decoder mplayer /music/WindowsMedia/ --outdir /music/mp3/
Unfortunately, I stink at Perl, so a lot of my Perl code looks like C. I tested the patches on my personal WMA Lossless collection on two different installs of ZenWalk Linux. Therefore, I hereby grant this code the honorary Scott Hanselman badge of “Works on My Machine.”
You can download the patched Perl script here: pacpl-wmal-patched.tar.gz
I’ll send the patches up to the maintainer of PACPL, but I’m not sure if he’s interested (or if he’ll recoil in horror at my code). I’ll add a comment if I hear back from him.
UPDATE: Turns out that I accidentally switched the Artist and Album Artist metadata tags, which is critical for iTunes. I fixed it and re-uploaded the tarball.
I still buy CDs. And until Amazon.com or iTunes starts selling music in a lossless format, I’ll likely continue to do so. However, I rip CDs to my PC immediately after purchase, leaving me with the problem of where to store the CD. Dumping the CD jewel case and storing just the CD and liner notes can save a ton of space, so I decided to buy some thin CD sleeves.
You can buy plain paper CD sleeves from numerous sources, but they usually don’t have room for liner notes. There are also many CD cases with built-in sleeves available, but they’re usually pretty crummy. The sleeves are often made of cheap plastic that tears easily, and can stick to the CD. They rarely have a slot for the liner notes, and you can’t remove the sleeves from the case.
Slappa makes the best CD sleeves I’ve found. Each sleeve has a fabric slot for the CD and another slot with a matte polypropylene clear cover for liner notes. They are stitched around the sides instead of glued or melted, so they won’t come apart over time. They have an optional interlocking slot system that let’s you easily remove and re-sort a CD collection. A single sleeve holds two CDs and two liner notes, and Slappa sells a model that holds four CDs for two double-CD sets. These things are fantastic.
I intended to buy the sleeves on their own, but it was a tad cheaper to buy them with an included case. The cases are impressive too – very rugged. There is a pocket in the front of the case that I use to store the back sides of CD inserts.
Slappa also makes a version of the sleeves for DVDs. I bought a set of them and tossed the original cases for a bunch of movies and video games. It’s amazing how many DVDs and video games you can store in a single drawer after ditching their cases.
I ordered everything directly from the Slappa web site, but it looks like they are now also available on eBags.com, possibly with cheaper shipping.
The only downside is what to do with the leftover CD jewel cases. It turns out that they are very difficult to recycle, and can’t be put in the recycling bin. Apparently, you can mail them to a couple of companies who will then try to re-sell them or grind them up, but I’m not sure I want to pay to mail hundreds of empty cases somewhere. If you know of any ideas, please post a comment.
