Is A FLAC File Better Than MP3?

Choosing between FLAC and MP3 can be a somewhat confusing prospect given the technological complexities of digital audio encoding formats. The fact that FLAC is lossless and MP3 is lossy might lead one to assume the former is superior. But is a FLAC file better than an MP3?

FLAC files are better than MP3, though the sound difference is usually negligible. This lossless compression format encodes input audio without losing information. MP3 performs lossy compression, discarding sound information that is non-essential while introducing noise to the output signal.

FLAC provides superior sound quality when compared to MP3. The degree of deviation between the quality of these formats depends, however, on multiple variables. If you want to know why FLAC is superior to MP3, you might find the following information helpful and enlightening.

FLAC Is Better Than MP3

In most cases, FLAC files are better than MP3. If one is primarily concerned with sound quality, then FLAC is the superior format.

With lossless compression, FLAC compresses audio without losing any components of the source sound information. This fact means FLAC encodes the complete range of frequencies and amplitudes in the original audio waveform. The result is a high-fidelity representation of the input audio in a smaller file.

Another reason FLAC files produce high-resolution sound quality during playback is that they invariably contain audio data in the LPCM format.

LPCM is an analog-to-digital sampling method that produces high-quality uncompressed audio data and is found most commonly on compact discs (CDs). FLAC files reproduce the complete sound range and quality level of the LPCM audio data they contain. For this reason, FLAC files sound as good as CDs.

In contrast, MP3 files employ lossy compression when encoding digital audio information. Lossy compression removes portions of the input audio information, so certain sounds are missing from the output audio. This lost audio information is largely inaudible though, so the difference between FLAC and MP3 is often negligible.

The exception is when file size is the principal consideration rather than sound quality. This might apply in scenarios where computer storage space and bandwidth are the priorities. In these scenarios, one might argue that MP3 is better because it compresses audio into smaller file sizes than FLAC!

FLAC

FLAC (Free Lossless Audio Codec) is the innovative open-source creation of the Xiph.Org Foundation. First released in 2001, FLAC is free to use. This lossless codec is unbound by royalties, patents, or proprietary restrictions and has a publicly accessible reference implementation program.

FLAC is the most efficient and universally compatible lossless audio format (which is partly due to its open-source design). In addition to the quality of FLAC audio, one of the codec’s notable advantages is its unrivaled decoding speed. 

FLAC Lossless Compression

As noted earlier, FLAC performs lossless compression, reducing the file size without discarding information from the input audio. Through lossless encoding, FLAC decreases file sizes by about 30% to 50% while reproducing a complete and identical representation of the original audio during playback.

Encoding

The FLAC encoding algorithm operates according to the following sophisticated sequence.

Firstly, the input audio information gets partitioned into blocks. An optimal mathematical representation (or approximation) of each block is subsequently derived through linear predictive coding or polynomials.

Next, the FLAC encoding algorithm writes a simple description (consisting of a few bytes) of the approximation for every block. Finally, the algorithm relies on Rice coding to encode the residual (the deviation between the approximation and the source audio).

Numerous interrelated factors affect the degree of compression that FLAC encoders apply to input audio, such as the number of bits in each block and the sequence used in the linear prediction model.

The FLAC reference implementation gives users nine (0-8) levels of compression to choose from when compressing an input waveform. Higher numbers in this range correspond with increased compression.

Applying a high compression level (5 or higher) slows the FLAC encoding process. However, the amount of compression does not affect decoding speed.

Decoding

When played back, the FLAC decoding algorithm first decodes the residual. The algorithm then formulates a waveform using the initial description of the mathematical approximation. This waveform is combined with the residual to produce the final, decoded output audio.

The decoded (or decompressed) waveform on a FLAC file is an indistinguishable replication of the original waveform.


Remarkably, compression levels do not affect the output sound quality of FLAC files. FLAC achieves the impressive feat of decoding an identical version of the input waveform regardless of the compression level applied during the encoding procedure!

FLAC And LPCM Audio Data

The type of data encoded by FLAC is another fundamental reason for the format’s superior quality compared to MP3. FLAC encodes linear pulse-code modulation (LPCM) audio data.

LPCM is a high-resolution technique for analog-to-digital sampling. This technique converts a continuously varying analog sine wave into a digital representation consisting of a finite number of binary values. The resulting digital audio is an identical, uncompressed, and unaltered version of the original analog signals.

Data sampled through LPCM is standard on compact discs (CDs), due to its high fidelity and resolution.

Bit depth and sampling rate (or frequency) are the two critical parameters that affect the fidelity of LPCM sampling. The most widely-used settings for these parameters for LPCM on CDs are:

  • bit depth – 16-bits,
  • sampling rate – 1411kHz.

LPCM audio is stored as raw sound information on files with the .raw, .sam, or .pcm extensions. In raw form, LPCM is headerless (without metadata) and not containerized (or held in a file with other data streams). In general, however, LPCM data is stored in an uncompressed form in container files like WAV and AIFF.

LPCM is also commonly encoded in the FLAC format. Though LPCM is compressed when converting to FLAC, its quality does not diminish. The lossless nature of FLAC compression means the encoder reconstructs the full range of tonal complexities present in the source LPCM audio.

Consequently, FLAC files retain and express the high quality of the input LPCM waveforms!

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MP3

MP3 (MPEG-1 and MPEG-2 Audio Layer III) is a codec that has played a pivotal role in the evolution of digital audio compression.

Released in 1993 by the Fraunhofer Society, MP3 was the dominant lossy compression format throughout the nineties and continues to be used widely in a range of applications.

Later versions of MP3 offer significantly improved performance compared with the first generation of the codec. MP3 is, however, increasingly being supplanted by the newer AAC (Advanced Audio Coding) lossy format.

MP3 And Lossy Compression

MP3 lossy compression decreases file sizes dramatically. The average MP3 encoding makes files about 75% to 95% smaller than the original uncompressed audio!

MP3 encoding achieves this decrease in file size through lossy compression, which removes certain sound information from the source audio signal. Due to this function, MP3 is called an irreversible compression format

Psychoacoustic Modeling

MP3 encoders determine which information to discard or retain through the perceptual coding (psychoacoustic modeling) method. Perceptual coding strategically exploits psychoacoustic limitations in the human auditory system. The sounds that people can’t readily perceive are identified and removed.

One of the limitations of human hearing is called audio masking. Audio masking is a phenomenon where one sound conceals another, which occurs when two sounds have the same frequency (frequency masking) or are heard simultaneously (temporal masking).

MP3 encoders identify masked sounds that listeners are unlikely to perceive and remove these inaudible (and thus inessential) elements from the audio signal. The result is a drastically smaller file containing a partial representation of the input audio.

Encoding

MP3 combines MDCT (modified discrete cosine transform) and FFT (fast Fourier transform) encoding algorithms to compress input audio signals.

Firstly, MP3 encoders compartmentalize the input signal into frames. Frames then get encoded through MDCT.

Next is the application of FFT to the frames. Psychoacoustic modeling is also applied at this stage, which removes inaudible and inessential sound elements. After perceptual coding, another round of MDCT filtering is performed on the resulting audio.

The following step is noise allocation, which entails audio sample quantification and encoding.

Finally, MP3 encoders format the audio frames (collectively called a bitstream) for storage and decoding. The formatting integrates the audio data with information such as a header and error check.

Decoding

When playing an MP3 file, the audio gets decoded according to an internal standard that specifies minimum accuracy (tolerance of rounding errors).

The decoding of an MP3 is less complex than the encoding process. Firstly, the frames get reconstructed as time-domain segments (showing signal changes in time). Individual segments then get connected to form a single bitstream.

The quality of the decoded MP3 audio depends significantly on the level of compression applied to the original sound information.

When MP3 encoders compress audio, they introduce noises and distortions called compression artifacts (also known as quantization noise). These undesirable noises become more conspicuous as one raises the levels of compression.

Comparing FLAC And MP3

So, FLAC is widely regarded as superior to MP3 because it performs lossless compression. But how significant is the quality difference between these formats? Is FLAC noticeably better than MP3?

FLAC files generally produce higher-quality audio than MP3 because they contain more original information and do not introduce compression artifacts. However, the difference in sound quality between FLAC and MP3 is negligible in most cases.

The deviations in sound quality between FLAC and MP3 are usually inaudible to the average listener. Even individuals with trained ears, like audiophiles, musicians, and sound engineers, might struggle to hear the difference.

There are, however, multiple factors that influence FLAC and MP3 quality comparisons.

Bit Rates And Compression Ratios

The ease (or difficulty) of differentiating between FLAC and MP3 depends heavily on the level of compression applied to the original audio signal.

As noted earlier, the compression level (ratio) of an MP3 file directly influences the quality of the output.  

Higher levels of compression result in a reduction in sound quality because less information is available to reconstruct the input waveform. In addition, higher compression cause a deterioration of the signal-to-noise ratio due to the introduction of quantization artifacts. 

The bit rate determines the amount of compression applied during the encoding process. Bit rate is the number of bits an audio file conveys per second during playback, conventionally measured in kilobits per second (kbps).

Increased bit rates equate to lower levels of compression, which produces a higher-resolution MP3 representation of the original audio. Decreased bit rates result in higher compression ratios, creating a concomitant decrease in audio resolution, while also increasing the presence of noise artifacts.

What are the implications of bit rates and compression ratios when comparing MP3 to FLAC? In essence, MP3 files encoded at high bit rates and low compression ratios are more difficult to differentiate from FLAC. At low bit rates and high levels of compression, MP3 files are considerably easier to distinguish from FLAC. 

Type/performance of MP3 encoders

The type of MP3 codec is another crucial variable when comparing this format with FLAC. Many MP3 encoders have emerged since the 1990s, with a marked difference in sound quality.

The first generations of MP3 codecs were rudimentary, relying, for instance, on constant bit rates.

The resulting output sound was low quality. Hearing the difference between the sound of these early MP3 encoders and FLAC is relatively easy and does not necessarily require a trained ear.

Later MP3 codecs used vastly improved lossy encoding algorithms with the capability to reconstruct input audio with little to no audible deviation.

These newer and more advanced MP3 codecs also apply variable bit rates. Encoding with variable bit rates enables more efficient use of the available bits, leading to higher sound quality during playback. 

At high bit rates, these more advanced MP3 encoders produce high-resolution audio virtually indistinguishable from FLAC.

Type Of Input Audio

MP3 is suited to simple audio with minimal variability in the frequencies and amplitudes present in the waveform.

For example, MP3 introduces minimal compression artifacts when encoding low-volume acoustic instrumentation. MP3 files containing this type of audio usually sound comparable to FLAC.

MP3 is less effective at encoding short, loud high-frequency sounds produced by percussive instruments like claves and triangles. Consequently, MP3s with this input audio type are often relatively unchallenging to distinguish from FLAC files.

Audio Equipment

The quality, performance, and condition of the equipment one uses to listen to MP3 and FLAC files impact comparisons between these formats.

Audio hardware that affects sound quality includes:

  • amplifiers,
  • headphones or speakers,
  • cables.

It is easier to hear the difference between MP3 and FLAC files when using top-of-the-range, professional equipment in optimal working order. This kind of hardware produces clear, high-resolution audio that reveals subtle sound nuances and makes imperfections more noticeable.

Comparing FLAC and MP3 formats becomes more tricky when listening through audio equipment that has low-performance capabilities or is poorly designed and manufactured. For example, most people would struggle to discriminate between MP3 and FLAC when listening through a low-budget cellphone speaker!

Hearing Abilities

The limits of the human auditory system and variations in individual hearing abilities brings further complication to the task of comparing different audio formats like MP3 and FLAC.

Human Hearing And Its Limits

The typical human auditory system can perceive frequencies within a maximum range of 20Hz to 20kHz (less for sounds at the lowest and highest ends of the frequency spectrum).


In terms of volume, the average person can hear up to about 120 dB. Volumes higher than this threshold make the sound become increasingly unbearable to the point of causing physical pain.

The sound information that MP3 encoders remove through lossy compression is usually outside the frequency range that humans can perceive. Similarly, a notable proportion of the audio data that FLAC retains through lossless compression is at frequencies that are difficult or impossible to hear.

Limits in the dynamic range of human hearing also make the distinction between MP3 and FLAC more challenging to discern.

Most compression artifacts that MP3 encoding creates emerge at intolerably high volumes. One is unlikely to compare these formats at the amplitudes necessary to reveal the quantization noises created through lossy compression.

Individual Hearing Abilities And Listening Skills

An individual listener’s age and listening skills also affect their ability to hear the difference between FLAC and MP3.

As people get older, their hearing capacity diminishes. Sounds at the higher end of the frequency spectrum become increasingly difficult to perceive as one progresses in age. The implication is that an octogenarian will experience more difficulty discriminating between FLAC and MP3 than a teenager!

An individual’s listening skill also fundamentally influences their ability to differentiate between the sound quality of different formats. As a result, people with ears trained from years of playing or producing music are far more likely to hear the difference between MP3 and FLAC.

Conclusion

FLAC files provide higher-quality audio than MP3s. Unlike MP3, FLAC encoding retains the complete set of audio information present on the input waveform. This enables the reproduction of high-fidelity and resolution sound quality. FLAC’s superiority is also due to the high-quality LPCM audio the format contains.

Conversely, MP3 files contain lossy compressed audio, which is technically an incomplete representation of the original audio waveform. Nonetheless, it is generally difficult for the average person to hear the difference between FLAC and MP3 unless the latter is encoded at exceedingly low bit rates.

References

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