FLAC vs MP3: Which is Better?

If you are as interested in great audio as I am, then you have probably heard people talking about different encodings and formats for audio files.

There is a huge difference in quality when software translates physical phenomena into digital media. That gives rise to the question:

What is best way to encode audio file?

​Two examples of such audio formats are FLAC and MP3. In this article, I'll discuss the difference between the two, and which of them is better.

The Quick Version: FLAC vs. MP3

Choose FLAC When

  • You want the best sound
  • When file size doesn't matter
  • When you have good equipment

Choose MP3 When

  • The sound quality isn't important
  • When file size matters
  • When you don't have good equipment

Compression and Loss of Audio Detail

The first thing to know is that creating audio files for the general public is not just about capturing a sound in bits and bytes. The resulting file then needs to be compressed, so that it will be easy to distribute.

Without compression, audio files can be very large. That makes them harder to store and take longer to download. Even with today's memory capacities and Internet speeds, it is generally impractical to distribute music or other audio without compressing it.

There are two main kinds of compression: lossy and lossless.

Lossless compression creates a file that is smaller but has the exact same audio information as the original file. Lossy compression can make the resulting file significantly smaller, but at the cost of sacrificing some of the original data. That means that while a lossless file is "bit-identical" to the original, a lossy file is not.

Lossy codecs try to minimize the impact this has on the listening experience. That has a clear implication for the quality of each codec.

Surely, a lossless codec should always beat a lossy one, right?

Actually, that isn't always true. After going over the history of FLAC and MP3 we will explain how the two encodings compare in terms of quality and ease of use.

History of FLAC and MP3

FLAC is an open source project. It first hit the market in 2001 and has been growing in popularity every since. FLAC is probably the most well-known and popular of the lossless encodings.

While it is still not common to see FLAC offered as an option for a lowland, even though it has attracted enough buzz. This trend is altering.

windows 10 supports flac

Recently, both Windows and Android have moved to add support for FLAC to their core operating system's tasks. As long as you have the most recent version of these OSs, then you won't need to hunt down extra software to play FLAC files.

The MP3 format has a checkered past. It was very popular on the music pirating website Napster and still enjoys an edge among pirates for its balance of file size and quality.

However, MP3 has grown to become one of the most popular codecs in the world across many different segments, from sales of new albums to recordings of interviews. MP3 is not the only lossy format, and FLAC is not the only lossless one. Both have their own competition, but their popularity sets them apart.

Bitrates

bitrate of flac vs mp3

So if FLAC is lossless and MP3 is lossy, then that means that FLAC is always better, right?

Not so fast. MP3 makes big cuts in the data contained in the original file. But the person who encodes the file into the MP3 format actually has some control over how much original data the MP3 retains.

As a result, two different MP3s of the same source audio can sound very different.

The key characteristic is called the bitrate. The bitrate is the number of bits of data within each minute of audio in a lossy encoding. A lower bitrate means there is less data and, therefore, less detail. A higher bitrate means more data and greater detail.

The bitrate of an audio file is very similar to the differences between the different kinds of digital TV signal. HDTV signals can come in 480p, 720p, 1080p, and so on. Larger numbers mean there is more detail and more pixels in the signal.

An MP3 with a low bitrate, such as 96 KB, will sound much worse than one encoded with a bitrate of 320 KB. That complicates the original question because there is no single standard for MP3 quality. The bitrate changes the whole listening experience.

Comparison

While higher bitrates do mean more of the original data shows up in the MP3 file, the real question now is what level of bitrate, if any, will place an MP3 on an equivalent level to FLAC.

FLAC never has a bitrate because it retains all of the original data. Even though higher bitrates have more data, there are limits to how much the human ear can perceive.

There is a subjective element to this as well. In general, though, a bitrate of 256 KB is difficult for anyone to distinguish from a FLAC file. Some people do claim to be able to hear the difference between even the highest level of recording, 320 KB, and FLAC. However, they are never able to prove this in a blind test.

Therefore, it is difficult to justify adhering to FLAC if there is an MP3 with a high bitrate available. The key is to compare apples to apples: it should be the exact same source file converted to both FLAC and MP3, not different songs in different formats.

Importance of Hardware

The hardware that you use to play back the audio makes a very big difference. For example, a good set of headphones can bring out far more detail in music than cheap ones.

However, this comes at a cost: poorly mastered songs or audio files that are too heavily compressed will actually sound worse on good headphones.

In other words, good headphones make the differences between lossless and lossy compression much easier to hear. So while it may not have been a large difference between a 120 KB MP3 on some Apple earbuds compared to the equivalent FLAC file, on a good set of Audio Technica, the difference will be very obvious.

If you, like me, want to have really good playback equipment, that means you must also seek out good source files. Your music will only ever be as good as its source. So if you are running low-bitrate songs through headphones or good speakers, it will sound bad and distorted.

That is one reason that codecs only matter to the audiophile community. Most people don't have the equipment to make the deficiencies in lossy codecs stand out. Only people like us who invest in good equipment will be able to detect a difference in performance. That is why so many audiophiles prefer lossless codecs: they know that they are making the most of their gear.

Conversion

You can convert between these different codecs without much trouble, because there are lots of programs that can do it fairly quickly.

However, a word of warning.

You can convert from a lossless format to a lossy one, but never the other way around!

This is because a lossy compression loses data forever. You cannot get it back by converting back to the lossless format, and the quality will not improve.

Many people fail to understand this: they take a poor-quality source MP3 and attempt it to convert to an MP3 of a higher bitrate or a lossless codec like FLAC. But even though the conversion will take place without a software error, the audio will not improve at all.

There are some good reasons to compress audio: MP3 does a very good job of saving memory space, while FLAC files take up quite a lot of space. But keep in mind that you can never go back up the ladder. So keep a lossless source file and only downgrade a copy of that. You should also convert to a high-bitrate MP3 to ensure that you are not losing too much quality in the process.

Final Verdict

It should be clear now: low bitrate MP3s are worse than FLAC, and high bitrate MP3s are more or less the same. Know what you are working with and you will always have the right expectations for your audio.

Got any questions or thoughts? Sound off in the comment section.

Like many questions in the audiophile community, this is a major debate because hearing is so subjective. If something sounds good to you, it isn't "wrong" or "bad" in any way. The motto for wine is "If it tastes good, it is good" and the same standard applies here.

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