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What is the difference between MP3 and lossless sound quality?

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What is the difference between MP3 and lossless sound quality?

Is it possible to distinguish Mp3 quality from CD Quality?

Although the sound quality of a CD does not reach the true hearing limit of the human ear, it is impossible for most people to tell the difference between a CD and a higher sampling rate, so everyone assumes that the CD sound quality is 44.1 kHz can be converted to lossless sound quality.

In the past, the capacity of storage media was not large. To store more music and make it easier to stream, we used to compress large CD audio files. High frequency and low volume sounds are removed to achieve the purpose of reducing file size. Similar formats include 3GP, M4A, AA3, WMA, etc.

With the development of the Internet and storage media, the size of audio files is no longer important, so lossless compression has gradually become popular. Common formats are APE, FLAC, etc., which are similar to the beginning of ZIP compressed files, compress audio files AND packed, the final file size is basically only half of the original CD file. Here it is emphasized that the WAV format we often say is a waveform record file, which uses uncompressed PCM encoding, which is also a relatively large WAV file. 44.1 kHz 16-bit WAV audio can also be considered uncompressed. Lossless sound quality.

Since different devices support different audio compression formats, we often need to transcode, and each transcode will cause some loss in audio. For example: If you convert MP3 to lossless format, you can only achieve the sound quality of the original MP3 file. This lossless can also be called false lossless. This is the case for most lossless music provided by music portals.

I have been recording for many years and have used speakers ranging from tens of thousands to millions of dollars. Why do I rarely use speakers under 10,000 yuan? Because speakers under 10,000 yuan cannot be used as monitors. I advise everyone not to charge money for listening to music on music portals for lossless sound quality. Untrained ears will not be able to hear the difference between true and false without loss. For normal ears, MP3 with a bit rate of 320 kbps is already the best.

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What is the difference between MP3 and lossless sound quality?

Now, many people think that it is impossible to listen to MP3, so they search for lossless music everywhere on the Internet.

So what is the difference between lossless music and MP3? What about the various lossless music formats?

A few days ago, a friend of mine bought a Porsche sports car and then came to ask me for lossless sound quality music. I told him there was no need to play MP3s, but people weren’t happy. The sound in the car was fine. Playing MP3 is a loss of audio.

Now there are many music websites that give lossless to the myth, but do you know what lossless is? What is the difference between lossless music and ordinary MP3? Today I come to talk to you about those things that have no losses.

I remember when Apple held the Iphone4 conference, it came up with a definition: retina display. In short, it has been replaced by a high resolution screen with pixels that exceed the recognition limit of the human eye since the Iphone4. I must say that Mr. Qiao’s trick is very good, he defines a word that everyone can accept and makes Apple mobile phones sell all over the world.

However, the same concept is much older in the world of acoustics. Sound is a type of energy wave. After the experimental research of countless generations of ancestors, it is believed that 40 kHz is a value that can well restore the sound heard by the human ear. Later, for various commercial reasons, some record companies defined the sample rate of CDs at 44.1 kHz, which they considered to be the “retina display” that the ears could hear. Later, 44.1 kHz brought innumerable problems to subsequent generations, because it is not an integer and cannot be divided and multiplied simply by performing SRC sampling, so early Inter defined the output sample rate of the sound card as 48 kHz to save problem. , which creates a sample rate conversion problem that all sound engineers hate

I can’t even hear the difference between lossless music and 320k MP3 Part 2

Is it necessary to buy headphones with good sound quality?

First of all, it is worth seeing it this way. Of course, most of the current lossless formats (except WAV format) do not refer to the direct storage of the original PCM stream, and still use a series of lossless compression algorithms to reduce storage space, but no matter how lossless Compression, in general, is definitely not as powerful as “lossy” compression.

Here, we have reached the first climax of the brain, obviously, in addition to using a series of compression algorithms to reduce the storage space of audio information, we can rely on more direct and rough methods, such as switching from binaural to monophonic. In this way, the storage space can be saved basically in half, but it is obviously not worth it. After all, two channel sound is still stereoscopic, and single channel doesn’t have that feeling at all, so we can start. of the sampling precision. , For example, the sampling precision directly reduces to 15 bits, which can directly save 6% of the space.

But in any case, reducing the sample depth must mean that the audio signal is corrupted (in fact, based on the current level of technology, no matter how you store it, the original audio signal cannot be restored)

So how does this “lossy” sound different?

blind listening test
Of course, practice is the only criterion to prove the truth. It doesn’t matter if you can do it or not. We cannot feel that the songs we listen to now are not good as soon as we hear the damage. they must more convincingly identify your sense of hearing. The difference between the two depends on the ABX Blind test.

I can’t even hear the difference between lossless music and 320k MP3

Is it necessary to buy headphones with good sound quality?

lossless and lossy audioz — lossless and lossy audio

1. It is basically impossible for a normal human being to tell the difference between lossless and 320K MP3 in safe listening volume (maximum volume does not exceed 90dB) and general environment (environmental noise greater than 30dB). [1]

2. Generally, people’s distinction between lossy and lossless high bitrate comes from adjusting the volume during the compression process, especially on various streaming media platforms – what you hear is not the difference in quality of the sound, but the difference in volume. .

2.1 The above conditions also apply to most equipment (decoders, amplifiers) for listening comparison.

3. To hear the difference between lossless and MP3, use the following methods:

3.1 Use low bit rate MP3 (128 and below)

3.2 Increase the volume to dangerous levels (may cause permanent hearing loss)

3.3 Repeat a specific segment continuously (it is generally recommended to control the repeated segment within 2s~5s) [2]

4. In normal listening situations, there is no point in being obsessed with differentiating between 320K MP3 and lossless. But it still makes sense to buy good headphones/speakers, because the human ability to distinguish the sound from different headphones/speakers is much stronger than the ability to distinguish the sound source.

Why do we need compressed audio formats?
This question is a bit stupid. Of course, it is to save audio storage space. If you do the math, even a 3-5 minute song at 320kbps probably only takes up a few megabytes of space, but if it’s an uncompressed format, the most popular 44100HZ sample rate, two channel, quantized PCM stream to 16-bit sampling, 3 minutes need 3x60x44100x2x2 bytes, about 30M storage space, so the space for a single song can be stored using MP3 to store 5-10

Converting mp3 to flac or wav in audio is useful? Improve sound quality?

We know that sound is produced by the vibration of objects, and sound propagation must occur in a given medium.

The propagation form of sound in the medium is a wave, and the sound wave is a kind of mechanical wave.

In order to store sound waves, the analog medium was invented. Vinyl records and magnetic tapes essentially simulate mechanical waves through electromagnetic waves. If we put the groove of the record under a microscope, we can see the original waveform of the sound, which is continuous.

The shortcomings of analog media are obvious, such as large size, difficult to transport, and little interference during the transmission process (analog TV snow spots, transmission noise, etc.). So, in the 1980s, Sony and Philips jointly developed the CD. CDs are a completely new form of storage. Its principle is to sample continuous waveforms, that is, to replace continuous waves with discrete points in the waveform (think of the tiny particles and pixels seen after a photo is enlarged many times).

The main concepts in the sampling process are as follows:

1. Bit depth

Obviously, the more points we put into it, the finer the (binary) sampling will be. We can understand it this way, assuming the sample rate is 1 bit, then the converted audio track has only two points, 0 and 1, i.e. we are using a square wave to represent a sine wave. Sure, the high points, the low points and the mid points are lost, we lose the dynamic range. 1bit = 6.02db of dynamic range. The sampling rate of the CD is 16 bits, that is, there are 2^16 = 65536 points. This music is difficult for most human ears to distinguish, and the dynamic range reaches 96db. However, in the actual listening environment, due to noise, etc., it cannot reach this range. So there is 24-bit or even 32-bit music.

2. Sampling rate

If we place the waveform in the coordinate system, the bit depth is equivalent to the fineness of the ordinate. The fineness of the abscissa is called the sampling frequency. Imagine a sound wave vibrating 20,000 times per second, if we can only collect 10,000 times per second, then we lose 10,000 vibrations and lose information. The frequency that the human ear can hear is between 20 and 20,000 Hz. According to Shannon’s sampling theorem (also known as Nyquist’s theorem), when the sampling frequency is greater than or equal to twice the highest frequency of a waveform, we can express this without waveform segment distortion. The CD sample rate is 44.1 kHz = 44100 > 20000 * 2. As for why it’s 44.1 instead of 40, on the one hand it leaves some room for the anti-aliasing filter, and on the other hand it supports PAL and NTSC video formats.

3. Bitrate

Finally, use bit depth * sample rate * number of channels to get the bit rate (bit rate) of a piece of audio, which is the number of bits passed per second. Taking a CD as an example, 16 * 44.1k * 2 = 1411.2 (kbps)

Our usual decoder (DAC) actually reverses the analog-to-digital conversion process of this sample, that is, the digital-to-analog conversion.

As for the music format, wav is a format jointly designed by Microsoft and IBM to store waveforms. The standard wav format is the same as the CD format, so we often call it lossless music (in fact, this statement is not rigorous), of course, wav can also store music with a lower bit rate.

The biggest disadvantage of wav is that it is too big. For small storage devices in the early days, wav is obviously not ideal. So, people developed various compression algorithms, like mp3, wma, etc. The mp3 format can compress a lot of space, but some of the information is removed during the compression process, so this process is called lossy compression, which corresponds to what we call lossy mp3 music. (Common bit rates are 128 kbps and 320 kbps)

When everyone’s hard drives are getting bigger and bigger, many people are not satisfied with the sound quality of mp3 compression, but at the same time they still feel that the wav is too big. Appear. The so-called lossless, because wav doesn’t lose any information when compressed into flac. This process is lossless compression, and flac can be decompressed into wav intact. Imagine that we compress the file in zip or rar, obviously no information is lost during the decompression process.