audio format in multimedia Archives

Digital Audio Quality

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Digital Audio Quality

Data rate refers to the data flow used by a video file in a unit of time, also called bit rate or bit stream rate.

The popular interpretation is the sampling rate, which is the most important part of image quality control in video encoding. Generally, the units we use are kb/s or Mb/s. Generally speaking, at the same resolution, the higher the code stream of the video file, the lower the compression ratio and the higher the image quality. The higher the code stream, the higher the sampling rate per unit time, the higher the data stream, the higher the accuracy, the closer the processed file is to the original file, the better the image quality, the clearer the image quality and the higher the decoding capability of the playback device is required.

Of course, the larger the code stream, the larger the file size. The calculation formula is file size = time X code rate/8. For example, a 720P RMVB file with a 1 Mbps stream of 90 minutes is common on the Internet and its volume is = 5400 seconds × 1 Mb/8 = 675 MB.

Generally speaking, a video file includes images and sounds, just like an RMVB video file, which contains video information and audio information. Audio and video have their own sampling methods and different bit rates, that is, the same video Audio and video file bit rate is not the same. And what we’re talking about is the bitrate of a video file, which generally refers to the sum of the bitrate of the audio and video information in the video file.

Taking the most popular and familiar RMVB video file in China as an example, VB in RMVB refers to VBR, which is short for Variable Bit Rate. The Chinese meaning is variable bit rate, which means that RMVB adopts dynamic encoding. In this way, a higher sample rate is used for complex dynamic images (singing and dancing, flying cars, wars, actions, etc.), while a lower sample rate is used for static images, and the resources are use rationally to achieve image quality and volume .Effect.

The most fundamental difference between code rate and sample rate is that the code rate is for the source file.

2. Sampling rate

Sample rate (also called sample rate or sample rate) defines the number of samples per second taken from a continuous signal to form a discrete signal, and is expressed in hertz (Hz). Sampling rate refers to the sampling frequency when converting an analog signal to a digital signal, i.e. how many points are sampled per unit of time. How many bits are in the data for a sample point? Bit rate refers to the number of bits (bits) transmitted per second. The unit is bps (bit per second). The higher the bitrate, the more data transmitted and the better the sound quality. Bit rate = sample rate x number of bits used x number of channels.

The sample rate is similar to the number of frames of moving images. For example, the sampling rate of movies is 24 Hz, the sampling rate of PAL format is 25 Hz, and the sampling rate of NTSC format is 30 Hz. When we play back the still images sampled at the same rate as the sampling frequency, we see a continuous image. In the same way, when a CD recorded at a sampling rate of 44.1 kHz is played back at the same rate, a continuous sound can be heard. Obviously, the higher the sample rate, the more coherent the sound will be heard and the picture will be seen. Of course, the sampling rate that human auditory and visual organs can distinguish is limited, which is basically higher than sound sampled at 44.1 kHz, and most people haven’t noticed the difference.

The number of digits in the sound is equivalent to the number of colors on the screen, indicating the amount of data per sample. Of course, the larger the amount of data, the more accurate the playback sound, so as not to confuse the sound. of the teapot with the train whistle. In the same way, it is more clear and precise for the image, so as not to confuse blood and ketchup. However, limited by the function of human organs, 16-bit sound and 24-bit image are basically the limits of ordinary humans, and the highest digits can only be distinguished by instruments.

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Detailed Music Format Part 2

Music CD

That is, CD records. A CD can play sound files of approximately 74 minutes. The Windows system comes with a CD player. Also, the software that comes with most sound cards provides CD playback functionality, and even some CD-ROM drives are offline. from computer Can be used as a stand-alone CD player when powered on.

WMA with unlimited potential

In developing its own network media service platform, Microsoft primarily promotes ASF (Audio Streaming Format), which is an open standard that supports data transmission over various networks and protocols. It supports audio, video, and a variety of other types of multimedia. And WMA is short for Windows Media Audio, which is equivalent to an ASF file that contains only audio.
The compression ratio of WMA files can be as high as 1:18 in 80kbps 44kHz mode, which is basically the same as VQF. And the compression speed is doubled compared to MP3. So it should be more competitive than VQF.

Vorbis free music format

To avoid rising royalties charged by MP3 music companies, programmers at GMGI’s iCast company developed a new free music format, Vorbis, that rivals or even exceeds MP3 in sound quality. And it will be released over the internet and can be downloaded for free without worrying about infringement issues. But MP3 has become very popular on the Internet, and Microsoft’s Windows Media technology has also started to spread, and Vorbis’s outlook is still not optimistic.

Other audio formats

AIF/AIFF: A sound file format developed by Apple, supported by the MAC platform, and supports 16-bit stereo at 44.1 kHz.
AU: SUN’s AU Compressed Sound File Format, which only supports 8-bit sound, is a commonly used sound file format on the Internet, mainly created by SUN workstations.
CDA: CD audio track file.
CMF: A MIDI-like sound file developed by CREATIVE.
DSP: Abbreviation for digital signal processing. By improving the signal processing method, sound quality will be greatly improved and songs will be more pleasing to the ear.
S3U: MP3 playback file list
RMI: MIDI Instrument Sequence

Lossy compression:

AAC – Sound quality is second only to MPC at high bit rates and looks good at both high and low bit rates. The encoding speed is too slow!
MPC: Performance is average at low bitrate, not as good as MP3 and OGG encoded by Mp3Pro, sound quality is best at high bitrate, and encoding speed is
fast.OGG: The sound quality is better at a low bitrate, and the same is true at a high bitrate. Encoding is slightly slower.
MP3 (MP3Pro): Sound quality is lower than OGG at low bit rate and other aspects are the same as MP3
WMA: High and low bit rates are average, VBR is not supported and the highest is 192Kbit/s

lossless compression:

FLAC – Worst compression ratio of the four, decent encoding speed, good platform support.
PAC: Slightly slower encoding speed, third in compression ratio, good platform support.
APE: The fastest encoding speed, the best compression rate, and the platform is generally supported.
WV: The encoding speed is very fast, the compression rate is second among the four types, and it is only supported by the Windows platform.

Detailed music format

classic wave

As the most classic Windows media audio format, the WAVE file is widely used, which uses three parameters to represent sound: the number of sampled bits, the sample rate, and the number of channels.
The channels are divided into mono and stereo, and the sample rates are generally 11025 Hz (11 kHz), 22050 Hz (22 kHz), and 44100 Hz (44 kHz). The capacity occupied by the WAVE file = (sampling frequency × sampling bits × channel) × time/8 (1 byte = 8 bits).

traditional mod

MOD is a wavetable-like music format, but its structure is similar to MIDI, it uses real samples, and the volume is small. In the earlier DOS era, MOD was often used as background music for games. Modern mods can contain many audio tracks in many formats, such as S3M, NST, 669, MTM, XM, IT, XT, and RT.

midi music computer

MIDI is short for Musical Instrument Data Interface. Records the sound played by the instrument digitally (each note is recorded as a number), and then synthesizes these records via FM or wavetable during playback: FM synthesis is the sound of the instrument is simulated by mixing the multi-frequency sounds; wavetable synthesis consists of storing the sound samples of the instrument in the wavetable of the sound card and extracting the sound from the wavetable as you play.

Boss Boss MP3

It can be said that MP3 is famous, it uses MPEG Audio Layer 3 technology to compress the sound with a compression ratio of 1:10 or even 1:12, with a sampling rate of 44kHz and a bit rate of 112kbit/s. .
MP3 music is music stored in digital form. If you want to play it, you must have a corresponding digital playback and decoding system. Generally, MP3 digital music is decoded by special software and then restored to a waveform sound signal for playback output. This type of software is called For MP3 players, such as Winamp, etc.

Overlord RA series online

RA, RAM, and RM are Real’s mature network audio formats, using “streaming audio” technology, making them well suited for network streaming. Information such as copyright, singer, producer, mail and song title can be added during production.
RA can be called the supreme lord of multimedia communication on the Internet. It is suitable for streaming on the Internet and is currently the best format for listening to online music online.

VQF with high compression ratio

VQF or TwinVQ is an audio compression technology developed by Nippon Telegraph and Telephone and Yamaha Corporation.
The audio compression rate of VQF is almost twice that of standard MPEG audio and can reach approximately 1:18 or even higher. And popular compression formats like MP3 and RA are usually only around 1:12. But it still won’t affect the sound quality, when VQF compress music at 44kHz-80kbit/s audio sampling rate, its sound quality will be better than 44kHz-128kbit/s MP3, when compress at 44kHz-96kbit/s , the music is close to 44kHz-256kbit/s MP3.

MD minidisc

MD (ie MiniDisc) is a comprehensive portable music format released by SONY in 1992. The compression algorithm it uses is ATRAC technology (the compression ratio is 1:5). MD is divided into Recordable MD (Recordable, with two heads of magnetic head and laser head) and Single Play MD (Prerecorded, only laser head).
The powerful editing function is the strong point of MD. You can quickly select tracks, move tracks, merge, split, delete and edit track titles. It is more personalized than CD and you can have your own MD album at any time. MD products include MD Walkman, MD bedside audio, MD car audio, MD recording deck, MD camera gun and MD driver, etc.

Do you know what is the best audio format? (for musicians and listeners)

Maybe you are a musician who has had the hard work of learning sound theory, writing and arranging your music, practicing, recording, and now you want to show your work to the world. What is the best audio format to distribute your recording? Or maybe you are a music lover looking for the best way to organize your collection. It may be that your collection comes from CDs or vinyl or even digitally downloaded. What is the best audio format to store your collection?

Choosing the right file format is important. On the one hand, the selected format affects the fidelity of the sound. However, the selected format also limits which devices can play your files. In this guide, we explain the different audio formats available, what they offer and how they are used in the best possible way. First, let’s understand what digital audio files are.

In short, what is the best audio format for you?
To choose the best audio file format you need, think about the purpose of each file. Here are some common uses with suggestions for the best audio formats for each:

If you are an artist …

Do you record a CD with your work? WAV! Conventional CDs use WAV, so export your music from DAW to Wav (or other lossless and then convert properly) and use these files to burn to CD. If you compress CDs from a factory, export in wav but in the original sampling rate and bit depth settings. Leave these settings to them.
Do you share your music with the public? Lossy! You want a smaller file size and maximum compatibility with them from your listeners. Any device plays an MP3 file and is easy to share online.
Should you distribute your music with Magroove or another aggregator for streaming services and online music stores? Streaming services have their own conversion systems, and each one works in a different format (the vast majority, lossy), so you probably won’t get a lossless song. Get a good mp3 that survives encoding (and is easier to load) and save Lossless versions somewhere, whether burning to CD or distributing to acts overseas!
If you are a listener or a collector …
Are you archiving your music? FLAC with maximum compression! A lossless compressed format such as FLAC or ALAC lets you store your files efficiently without losing sound quality. Records in the original multimedia format settings. CD, for example, 16-bit, 44.1 kHz.
Do you digitize music from a vinyl? Record at least in a lossless format. Read about the recording / conversion settings, especially sample rate and bit depth, and understand what lossless quality you need.

Digital audio format guide.

Since digital music has become popular, its fans have gradually developed the desire to hear it in the best possible quality.
For a time, the technical limits and the costs prevented us from achieving this goal, which is no longer an illusion.

The music streaming services market has never been so successful and we talk a lot about it in this article, but there are so many digital music formats … we’ve made this guide for clarity.

The teacher recorded in the studio is recorded at the resolution that defines the artist, but then the album we hear can be converted into a large number of more or less compressed formats, which, as shown in this infographic, into two large families are divided. . ::

Lossy audio formats: If the quality and the data contained are inferior to the original file, which leads to loss of detail, but to the benefit of the lightness of the file. These formats are widely used by streaming services like Spotify and take up less space.

Lossless: If the quality of the generated file matches that of the original master, without loss of quality, however, they require storage systems such as NAS and are not ideal for streaming via a mobile device connection.

Let’s start with the first Lossy family (AAC, MP3, Ogg Vorbis and WMA)

AAC

Advanced Audio Coding (MPEG-4) is the standard standard used by Apple for iTunes. Nostalgic people who had an iPod will remember that when CDs were imported into their MAC, the files were converted to this format. At the same bit rate, it takes up the same space as an MP3, but the conversion can be of higher quality.

MP3

An acronym for Moving Picture Expert Group-1/2 Audio Layer 3 is the world’s most widely used compressed audio format and was first introduced in 1998. The compression algorithm removes some details from the audio track that you can hardly hear The human ear By compressing a WAV file, you get an MP3 file that is up to 90 times lighter than the original. This depends on the bit rates or the amount of digital information (bits) that are transmitted or recorded in a unit of time. They can vary between 32 (poor quality) and 320 KB (excellent quality) per second.

OGG Vorbis

It’s an open source format with a quality comparable to MP3 that was unknown until recently, but is now used by services like Spotify. OGG is the file extension, while Vorbis is the compression algorithm.

WMA

Windows Media Player is the format invented by Microsoft in response to the MP3 standard. The quality is the same, but has the disadvantage that it is only compatible with devices of this brand.

Now let’s discover the features of the lossless family (FLAC, ALAC, AIFF, WAV and DSD).

FLAC

Free lossless audio codec. It is the most widely used open source format for downloading music without loss of quality compared to the original source. A fairly attentive ear can easily tell the difference from a smaller format, lower quality file.
iTunes does not support playback of this format because it uses its (ALAC).

A THE C.

The Apple Lossless Audio Codec or FLAC for the Apple world is only ideal if you use Apple branded devices, even if it does not correspond to the FLAC in terms of weight.

AIFF

This audio swap file format is also owned by Apple, which was developed based on the Electronic Arts swap file format and is particularly suitable for audiophiles and music producers. It has essentially the same properties as the WAV format, but without compression, and is used by artists because it can also be used to embed metadata such as text, notes or other information in the file.

WAV

The WAVE audio file format, introduced by Microsoft and IBM in 1991, continues to be used and represents what you get when you import a music CD to your Microsoft computer. When playing back a file of this format that can also be read by a MAC, a special function is used in the Intel CPU. These are very heavy files that reach a maximum of 2 GB and reproduce the sounds in a very faithful manner.

DSD

Direct Stream Digital is a registered trademark of Philips and Sony, developed for the Super Audio CD. An encoding method is used that uses a single bit instead of predicting a higher bit depth, but at a much higher sampling rate to record, store, and reproduce extremely high sound quality. The original sampling rate was 2,822 MHz and its format is known as DSD64