FLAC or mp3? Differences in lossless vs lossy audio sound formats
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What is the difference between lossy and lossless audio? Can you hear the difference? Which audio format is the best for your usage? Which one is better for sound files compression and which one to download? Why bitrate matters? Here I answer to all those questions below.

Lossless and lossy audio sound formats

In digital audio world in which we currently live in the source audio file is shortly speaking: a pack of many data samples, represented by numbers, which can be saved in two main possible forms:

Form 1: lossless audio file

(for example: Audio CD track, WAV, FLAC, ALAC)

Form 2: lossy audio file

(for example: MP3, AAC, M4A, OGG)

What is the major difference between those two forms?

Lossless audio file

They are very large.
1 minute of typical music WAV file (Stereo, 44.1 kHz and 16-bit) takes 10.09 MB (MegaBytes) space on the disk. Size of FLAC or ALAC is adaptive and will depend on the audio file contents.

When the correct settings are used, it's always a mathematically ideal and 100% correct representation of sound waves of the original recorded signal. It is recorded in this form, stored in this form, worked on, modified, mixed and mastered in this form in audio engineering studios, and then shipped in this form to the end user after buying in various lossless audio formats. The most popular lossless audio file formats today are: Audio CDs, WAV files, FLAC files, ALAC files.

Lossy audio file

Usually much smaller than lossless files.
1 minute of a typical 128 kb/s MP3 music file takes 0.94 MB (MegaBytes) space on the disk (320kb/s takes 2.34 MB).

Is always created first from the original lossless source file. Its main aim is to reduce the original source lossless file size by cutting various audio data and lots of simplifying and estimating algorithms (based also on the scientific understanding of human hearing), so that it can be shared on the internet, through streaming services, put in games and movies, and put on our music devices by saving disk space and internet bandwidth. In other words, it's quality per size optimization. The loss of original data from the source file is permanent - which means the original lossless audio file can never be restored from a lossy file. Lossy files come with various quality settings, represented by bitrate.

What is "bitrate"?

Simple word association which will help you memorize. Bitrate consists of two words: bit and rate. It shortly means that it's the rate at which the bits (computer data) are flowing in the audio stream - the more bits, the higher the rate of flow during one second. Therefore the higher the bitrate, the higher the size of the audio file will be, because those bits have to be stored somewhere. Because the computer will have also more data to work with, the audio quality will also be higher.

Very simple rules:

The higher the bitrate, the higher the audio quality and filesize.

The lower the bitrate, the lower the audio quality and filesize.

There are exceptions to these rules. See below for detailed info.

Differences in conversions and saving

In the previous paragraph about a lossy audio file I told you that:

The loss of original data from the source file is permanent - which means the original lossless audio file can never be restored from a lossy file.
This also means that reconverting a lossy audio file into another lossy audio file will reduce the quality even more, no matter of the bitrate used.

Important to remember:

Converting or saving a lossy audio file to another lossy audio file - even in the same format and with higher bitrate - will always result in lowering the audio quality even more. Therefore the conversion or saving to a lossy format should always only be made once - during the moment when converting from the original source lossless file - to minimize the resulting audio quality loss.

Case: Lossless saved to lossless

Converting a lossless audio file to another lossless audio file will never lower the audio quality, if the same settings will be preserved as in the original.

Case: Lossy saved to lossless

Converting/saving a lossy file to a lossless file will not improve the audio at all - it will just save exactly the same original lossy file, only making it much larger on the disk.

Which format should I use or download?

This depends on what you want to do with the audio files. Most usage cases:

Listening to music only (music playback)

You can safely only use lossy audio formats for this case in the highest constant bitrate allowed. For MP3 and OGG files it's 320kb/s constant bitrate. For M4A (AAC) you can even use 256 kb/s constant bitrate or more. If your files are converted from the original lossless files (Audio CD, FLAC, WAV) and those original files were not "fake" (reconverted from other lossy files from f.e. streaming services) you won't hear the difference even on a very high quality audio gear.

I don't personally recommend using variable bitrate, as it's not really predictable. The quality will be too uneven and therefore will sound overall worse (especially on the more calm music parts) than if using a constant (fixed) bitrate instead. Constant bitrate is also more compatible across various devices. Only use variable bitrate if you really feel the need for it.

Working with audio files (recording, editing, mixing, mastering, saving, converting)

In these cases only use lossless audio files, always. When opening, when saving, when recording, when exporting - at every moment. Nothing really more to add here, I think. Just try to remember to preserve the same Sample Rate, Bit Depth and Channel count. Otherwise your original audio quality may not be always preserved.

Exporting audio files for internet streaming services (Youtube)

In this case always try to use lossless audio files, if possible. Doing this will ensure that you won't lose your audio quality twice in a row, but only once. Your audio file will be converted anyway by your streaming service (like Youtube) into a lossy file, optimized for internet streaming. This is unavoidable. So it's best if this lossy conversion will only happen once, on the streaming service side. So you can only try not to do it also additionally on your side.

Thank you for reading

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Written by rezno[R].
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