Definition: savitech was originally a private Bluetooth audio coding protocol independently developed to meet the functional requirements of LDAC.
Hardware support: you need to support the LHDC at the bottom of the mobile phone system, or install savitech's LHDC Bluetooth player.
Audio algorithm: Although THD+n, amplitude-frequency response and noise floor in digital domain may not fully meet the theoretical limit performance requirements of hires audio files, it is indeed enough to play back lossless audio files of CD scratch.
In a word, LHDC is a relatively reliable private Bluetooth audio coding protocol.
gas concrete
Definition: the abbreviation of advanced audio coding, which is an excellent lossy format on the market at present. There are many kinds of coding, and the highest bit rate is 448kbps.
Hardware support: generally support advanced mp3 and mobile phones.
Audio algorithm: The compression ability far exceeds the previous compression algorithm, and it also supports up to 48 channels, 15 low-frequency channels, more sampling rates and bit rates, multi-language compatibility and higher decoding efficiency.
In a word, AAC can provide better sound quality on the premise that it is 30% smaller than MP3 files.
aptX
Definition: Digital audio coding formats for Bluetooth transmission, including standard mode, low delay mode (aptX LL) and high definition audio mode (aptX HD).
Hardware support: To achieve the effect of aptX, both the sender and the receiver must support aptX.
Audio algorithm: Compared with ordinary Bluetooth codec transmission format, aptX not only improves the sound quality, but also effectively shortens the delay phenomenon of Bluetooth.
In short, according to the official definition, aptX can make the transmission rate reach an astonishing 990kbps.
LDAC
Definition: The audio codec developed by Sony can encode more effectively.
Hardware support: Mobile devices supporting Android 8.0 and players equipped with LDAC technology.
Audio algorithm: The biggest feature of LDAC technology is to ensure the wireless audio transmission speed and sufficient information, which means that the sound is fuller when it is realized in the actual music listening sense.
In a word, LDAC is one of the Bluetooth transmission technologies closest to lossless transmission at present.
Acc is a common decoding method for Apple products, similar to sbc. It supports 44khz/ 16bit audio, the maximum bit rate is 5 12kbps, the delay is about 100ms, and the sound quality is slightly better than sbc.
CC is a technology provided by Dolby Laboratories for the music community, and it is a coding algorithm with high compression ratio. In practical experience, it is considered that ACC is better than MP3 at the same bit rate, and ACC on Apple has a lot of audio.
Therefore, the audio transmission format of the current iphone is also acc format, and the bit rate is equivalent to SBC, but it is said that the listening sense is better than SBC. Because there is no serious comparison, I think it is slightly better than SBC for the time being.
3.APTX
APTX is a patented coding algorithm of CSR company. After being acquired by Qualcomm, APTX has been widely promoted in Android phones. Official website:/I saw oppo and Nokia in the supporting equipment in official website ~
According to official website, aptX can be divided into three types: aptX, aptX HD and aptX low latency. From the name point of view, they are traditional aptX, high-quality aptX (probably to improve the code rate) and low-latency aptX (it is very important to watch video and play CS with delay).
Qualcomm aptX audio coding algorithm originated from Queen's University Belfast1late 1980s. The focus of this innovative work is to reduce the bit rate and achieve significant bit rate efficiency while maintaining audio quality.
AptX has always been the best-kept secret of the professional audio industry, and it is used by major public broadcasters and film studios around the world. AptX has been launched on leading consumer electronic devices, enabling music lovers to enjoy the rich listening experience brought by aptX.
Qualcomm probably means that aptX belongs to my family, and then the audio coding algorithm developed by Queen's University in 1980s. The algorithm has high bit rate efficiency while maintaining high audio quality. As a professional wireless audio transmission scheme, AptX has been used in public broadcasting and movie audio, and now it will finally be put into consumer products.
Therefore, the transmission rate of aptX is not high, which may be similar to the previous two. But thanks to efficient coding, more details of the sound are preserved, and the actual listening sense is better than the first two. AptX's publicity also claims that it can achieve CD-level listening.
4.LDAC
Now it's Dafa's turn to play. Dafa improved the channel simply and rudely. On the devices supporting LDAC, the communication code rate of Bluetooth is close to1m.
LDAC can transmit data about 3 times that of ordinary Bluetooth * 1 (the highest transmission speed is 990kbps *2), so that you can hear the sound quality close to Hi-Res Audio*3 music wirelessly.
At such a high transmission speed, it is possible to transmit lossless music. Of course, this almost proprietary transmission format also leads to compatibility with only a few devices. But there is no doubt that the transmission rate of LDAC has been greatly improved, which makes the transmitted audio quality higher and the listening sense is naturally the best.
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Original link: /shepinfangdaki/ article/details /54486 100