Mainstream audio format full-contact

Speaking of MP3, we have to consider the sources, a good MP3 player, plus good sources that can give us some more music to enjoy. Now let's look at the currently more popular audio formats and their features. What is a digital audio format, digital audio sources? "is a digital audio format, the first referring to the CD, the CD is compressed, and derive a variety suitable for play on the Walkman, the compressed format, can be divided into two broad categories: lossy and lossless compression. This compression, refers to PCM encoded or WAV format audio stream after a special compression, conversion into other formats, so as to achieve the effect of reducing the file size. Lossy/lossless, is compressed, the new document retention of sound signal relative to the original PCM WAV format of signal/is reduced. (Note: not the natural sound, because digital audio, relative to the natural voice, only infinitely close to non-destructive, to achieve true lossless is impossible, so common to PCM as the highest level of fidelity. ) Since there is a lossy compression, relative, it must be lossless compression. Lossy compression introduces the lossy compression of audio sources, in fact, we are more familiar with the current popular lossy formats are MP3, WMA, OGG, AAC, VQF, MP3pro, ASF, etc. MP3 format MP3 format is the most well known of all, the current user, the most popular online music files in MP3 format is also mostly.　　The full name is MPEG Audio MP3 Laye-3, it was born in 1993, his "parents" is Germany Fraunhofer Institute (Faunhofe IIS) and France Thomson (Thomson). Early MP3 coding technology is not perfect, for a long time, most people use 128Kbps CBR (fixed encoding rate) format to encode to MP3 file, until recently, VBR (variable coding rate) and ABR (average coding rate) compression, encoding bitrate up to 320Kbps, MP3 files on the sound began to make progress, and the emergence of the LAME; otherwise, this progress has brought about a qualitative leap forward, would we will describe how to use LAME this high-quality MP3 compression software to produce high quality MP3. WMA format in the vast majority of MP3 player, the most basic support two formats are MP3 and WMA. This shows the WMA format is also very important. WMA, Windows Media Audio, a discerning eye can see this is Microsoft's masterpiece. WMA relative to MP3 's biggest feature is the strong can be protected, it can be said that the introduction of WMA, MP3 is not drawback of copyright protection. Since Napste bankruptcy, Microsoft is more hype for WMA, MP3 to overthrow. Now it appears that the WMA is probably the most affected by the record companies are welcome to format. In addition to the copy-protected, WMA and MP3 sound quality and volume characteristics, on the contrast can be summarized as: low bitrate (< 128Kbps), small WMA MP3 volume ratio, sound quality is better than MP3, and in the high bit rate (> 128K), MP3 audio quality is better than WMA. MP3pro format WMA just started to pop, yet high-quality MP3, so that the status of MP3 really shaken, the Thomson Corporation in June 2001, in IIS, has released Faunhofe a new format — MP3pro, which is the improvement of the MP3 format, MP3 encoding algorithm is much more complex, simple, two-layer code, on the basis of the MP3, then with another technology (SB band replication technology) mixed encoding. MP3pro and MP3 compatibility, the original file extension with a .mp3, this format at low bit rate, compression efficiency is very high, so in general sound quality, and the bit rate of MP3pro size than MP3 or WMA are much smaller, and the sound quality is the best of the three. Technically, MP3pro is an excellent way of coding, but it's costly patent fees, making it not really popular, but at present as far as I know, only Thomsn machine can really support MP3pro format files. OGG format with MP3 player, MP3 player brand and more and more manufacturers are increasingly fierce competition, plus MP3 cell phone squeeze, many upstream MP3 Walkman manufacturers have to find a way out, there's the innovation in appearance, are working on a refinement, a large bulk of launch models, while on the decoding chip, the improved decoding capabilities, support for new file formats.　　In many of the new format, OGG to its free, open-source characteristics, has won the favor of MP3 player manufacturers. Here's the full name should be in OGG OGG Vobis. OGG is not a manufacturer's name, but a huge multimedia development plan of the project name, will involve video, audio and other aspects of coding development. Vobis is a musical work in a person's name, just use it to represent the OGG Vobis is easy on audio. OGG Vobis has a very outstanding characteristic is the support for multiple-channel, with it's popular, later by Walkman to listen to DTS-encoded multichannel entries will not be a dream.　　OGG Vobis in the compresses better than MP3 technology, but slightly inferior to MP3pro, but its multichannel, free, open source these characteristics, it is likely to become a popular trend, which is precisely one of the MP3 player on their support. At this point, we've got four popular lossy audio source formats, MP3 player, 4 kinds of format of the sound source is sufficient, as for ASF, A, VQF, AAC, etc. these, although each has advantages, but currently does not flowLines, support the WALKMAN is very limited, I also not waste ink to elaborate, here is their simple Windows Media ASF is described using a streaming media format, and Windows Media closely linked, in theory, the most stable; it is A namely ealAudio eal and the cooperation of Sony products with Atrac3, small file size, adjustments and online play, VQF is Yamaha products, the compression ratio is high, but not open source, not too many pop; Advance Audio Coding AAC,, advanced audio coding technology, Dolby Labs products, the quantitative level and supported sampling rates are very high, with support for multichannel sound, the sound quality good, but the hardware requirements are comparatively high, so few MP3 manufacturers willing to support that is currently only supported on their iPod, but also restricted to very common music file. Lossless compression Audio Lossless compression, you may also be unfamiliar, but this does not mean that lossless compression technology development is not good, on the contrary, in the area of lossless compression already has many wonderful works, such as APE, FLAC, WavPack, LPAC, WMALossless, AppleLossless, La, OptimFOG, Shoten, etc. Today, I will introduce several to (or most likely to be) in the MP3 player to play lossless compression format, hopefully with this article, so we have an understanding of lossless compression, also, to a certain extent, you can let everyone later when choosing MP3 player. FLAC first to introduce you to FLAC, because there are already several paragraphs camera support FLAC format. FLAC (Lossless Audio Codec Fee), the full name should be called OGG FLAC, because it is part of the OGG project, of course, is open source, free, no wonder it so soon got several MP3 factory support. FLAC compression can achieve 2: 1, lossless compression, this is a very high proportion; and it decoding speed, just for integer operations can complete the entire decoding process, CPU computing capacity requirements are very low, so ordinary Walkman, you can easily implement real-time decoding. Of course, this is the need for software support. FLAC is currently the only access to hardware support for lossless compression coding, MP3 player, now there are many car player and home audio device supports FLAC format. APE in writing this article, I was listening to the music of APE format, this allows the authors responded immediately, to introduce Audio Lossless compression format, APE is essential.　　Why? because APE in lossless compression areas is very popular, it is equivalent to the fields of MP3, everyone said that this format, I can not explain to everyone?, APE Monkey ' s Audio produced a lossless compression format that appear earlier than the FLAC and fame than large FLAC support it's software or more, I understand the lossless compression of music, but also from the APE. Before the advent of the APE, music fans are believed to CD or WAV to save their favorite music stuff is the best method, but the emergence of APE, enough to make them change this view because APE can keep the music signal of non-destructive and can be much more than A high compression ratio (nearly 2: 1) compressed WAV file, and you can play directly without having to unzip. APE of these characteristics, are other lossless compression format by the scrambling to follow suit. APE so popular on the Internet is also easier to download to a file, APE format, APE however need hardware and software support, there is no technology in the Walkman above, although the APE format as lossless, the sound quality is guaranteed, but no manufacturer developed playing APE format Walkman. About APE format episode here the author to insert a little episode, is used to describe lossless compression can really do. I have talked with several short song line friends discussed an issue: APE lossless is real, or just a very small losses are negligible. Although I've ever seen, support APE is truly lossless, but a bit short song line friends presented his own opinion, "so is truly lossless, why in production, you can select a compression quality?" was the author of the first reaction is: the compression quality should be followed by A compression quality as well, with operation time for compression, but after all, has not been personally, so I was not immediately retorted that old friends, but is immediately carried out a little experiment: to a WAV file, check its WINMD5 MD5 code, logged, and then use the Monkey ' s Audio on it to different compression quality compressed so that it becomes the APE file, and then extract the APE files into WAV, finally comparing several WAV file MD5 code and found several WAV file MD5 code is exactly the same, it is sufficient to prove that the WAV-WAV > APE-> is truly lossless. Interested readers can also use this method to examine other lossless compression format that is truly lossless too. AppleLossless AppleLossless this audio format, a look that is Apple's masterpiece. This format produces very convenient, you can directly put iTunes music CD produced AplleLossless file. However, only Apple their software to play out. Although this format does not have any outstanding characteristics, compatibility is not strong, but after all, has received the support of the iPod, so we cannot ignore their existence. WMALossles and AppleLossLess similar, called WMALossless format. Needless to sayIt certainly is a Microsoft product. WMALossless don't know should be regarded as a WMA, since its extension WMA, after all it is. WMALossless production is also very convenient to use WMP can capture directly from the CD, but the WMP version 9.0 will support this functionality. Most MP3 players support WMA format, but I just use your own MP3 player test, it does not support playback of WMALossless, but directly skip this file.　　The author believes that if WMALossless is a WMA, then decode methods should not be too big to let MP3 players support WMALossless possibilities or very large. The audio format is currently more popular audio formats, and understanding how these formats, next the next article, we will introduce some graphs wenbingmao MP3 Walkman on commonly used audio formats for creation and related software use, so stay tuned.