The difference between WAV and FLAC

digital-audiofile formatflaclosslesswav

My understanding is that the WAV and FLAC formats are containers for lossless audio. I have seen the FLAC format as being perhaps better because it is able to losslessly compress audio from say a WAV file.

However today I noticed that bleep is offering both WAV and FLAC files to download. Is their practice redundant or am I missing something?

After reading allquixotic and
slhck answers I was curious as to the
audio codec for the wav files in question. This is what I found

Input #0, wav, from 'Exai-001-Autechre-Fleure.wav':
  Duration: 00:04:51.39, bitrate: 1411 kb/s
    Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz,
                 stereo, s16, 1411 kb/s

Best Answer

You might be confused about different concepts:

FLAC is a lossless audio codec (its container also happens to be called FLAC, but the main idea here is the actual codec).
WAV, on the other hand, as a container can hold numerous kinds of audio codecs, but mostly, you'll find PCM-encoded audio.¹

Since FLAC is all about mathematically lossless compression, FLAC files will be smaller than corresponding PCM-encoded WAV files, since PCM doesn't allow for lossless compression and just represents the data as-is.²

So, simply put: Take a WAV file with PCM-encoded audio, and the corresponding (mathematically equal) FLAC file will be a tad smaller. The downside is that FLAC is not as widely supported as WAV. For example, most (all?) operating systems won't play or convert FLAC files without extra software.

Bottom line, I'd say their practice is redundant but a nice gesture for folks who don't want to download massive amounts of data and prefer the compressed version.

_{1 – For example, variants of MP3 can also be stored in a .wav file.}
_{2 – The analogy for images would be that BMP files contain the raw image data in an uncompressed form, whereas a (lossless) PNG is much smaller, but showing the exact same contents.}

Related Solutions

Audio Compression – Why FLAC from MP3 is Bigger than MP3

The reason the FLAC is larger than the MP3 of the same data is because they encode differently. :) MP3 just encodes perceptual information, while FLAC stores every single speck of data, just in a more compact format.

Converting a WAV to a FLAC is like converting a BMP to a PNG.
- Same exact pixels, but compressed losslessly like a ZIP file into a smaller size.
Converting a WAV to an MP3 is like converting a BMP to a JPEG.
- Instead of storing exact pixels, it's really storing instructions for generating squares with ripples of color that look kind of like the original.

Similarly, MP3 just stores instructions for generating ripples that, when added together, sound kind of like the original. But the difference between the true signal and the generated signal (the error signal) consists of random noisy artifacts, like JPEG jaggies. When you then store this in a perfectionist format like FLAC, it needs to store all those jaggies, and random noise is harder to compress losslessly, so it increases the size of the file. (Truly random noise is incompressible. When you compress a file losslessly, you're eliminating redundant repeating patterns and making it look more like random noise.)

I bet if you convert the JPEG to PNG you will see the same kind of increase in size as you see when converting MP3 to FLAC, since the perfectionist lossless codec needs to remember every little jaggy and artifact that wasn't in the original bmp.

This analogy isn't perfect, since audio is more like a photo than a line-art diagram, but it helps get the idea across:

Original BMP size: 29 kB

Blue dots in PNG form

PNG size: 629 B

Blue dots in JPEG form with jaggies

JPEG size: 1.7 kB

Blue dots with jaggies re-encoded to PNG

PNG created from JPEG: 6.2 kB

Linux Audio – Join MP3, OGG, and FLAC Files into One WAV or FLAC

You can do this with ffmpeg and sox:

for i in *.mp3 *.ogg *.flac
do
  ffmpeg -i "$i" "$i.wav"
done

sox *.wav combined.wav

Best Answer

Related Solutions

Audio Compression – Why FLAC from MP3 is Bigger than MP3

Linux Audio – Join MP3, OGG, and FLAC Files into One WAV or FLAC

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