FLAC encoding of WAV fails with error of unsupported format type 3

Whenever I purchase music from Bandcamp, SoundCloud, or other music sites that offer uncompressed, full-quality downloads (I can’t bring myself to download anything but original or lossless music files), I will always download the original WAV if it is offered. I prefer to keep the original copy around just in case, but usually I will put that on external storage, and use FLAC compression for actual listening (see my post comparing FLAC compression levels, if you’re interested).

Typically, my workflow for getting songs/albums ready is:

• Purchase and download the full-quality WAV files
• Rename them all according to my naming conventions
• Batch convert them to FLAC using the command line (below)
• Add in all the tags using EasyTag
• Standardise the album artwork
• Add the FLAC files to my playlists on my computers and audio server
• Batch convert the FLACs to OGG Vorbis using a flac2all command (below) for my mobile and other devices with limited storage

It takes some time, but it’s something that I only have to do once per album, and it’s worth it for someone like me (read “OCD”). 😉 For good measure, here are the commands that I run:

Batch converting files from WAV to FLAC:
find music/wavs/$ARTIST/$ALBUM/ -iname '*.wav' -exec flac -3 {} \;
obviously replacing $ARTIST and $ALBUM with the name of the artist and album, respectively.

Batch converting files from FLAC to OGG using flac2all:
python2 flac2all_v3.38.py vorbis ./music/flac/ -v 'quality=7' -c -o ./music/ogg/

By the way, flac2all is awesome because it copies the tags and the album art as well. That’s a huge time saver for me.

Normally this process goes smoothly, and I’m on my way to enjoying my new music rather quickly. However, I recently downloaded some WAVs from SoundCloud and couldn’t figure out why I was coming up with fewer FLACs than WAVs after converting. I looked back through the output from the command, and saw the following error message on some of the track conversions:

05-Time Goes By.wav: ERROR: unsupported format type 3

That was a rather nebulous and obtuse error message, so I decided to investigate a file that worked versus these ones that didn’t:

File that failed:
$ file vexento/02-inspiration/05-Time\ Goes\ By.wav
RIFF (little-endian) data, WAVE audio, stereo 44100 Hz

File that succeeded:
$ file vexento/02-inspiration/04-Riot.wav
RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz

The differences are that the working files indicated “Microsoft PCM” and “16 bit.” The fix for the problem was rather simple, actually. I used Audacity (which is a fantastic piece of cross-platform, open-source software for audio editing), and just re-exported the tracks that were failing. Basically, open the file in Audacity, make no edits, and just go to File –> Export –> “Wav (Microsoft) signed 16 bit PCM”, which you can see in the screenshot below:

Click to enlarge

Just like that, the problem was gone! Also, I noticed that the file size changed substantially. I’m used to a WAV being about 10MiB for every minute of audio. Before re-exporting these files, they were approximately 20MiB for every minute. So, this track went from ~80MiB to ~40MiB. 🙂

Hope that helps!

Cheers,
Zach

P.S. By the way, Vexento (the artist who released the tracks mentioned here) is amazingly fun, and I recommend that everyone give him a chance. He’s a young Norwegian guy (actually named Alexander Hansen) who creates a wide array of electronic music. Two tracks (that are very different from one another) that I completely adore are Trippy Love (upbeat and fun), and Peace (calming yet cinematic).