Secondary posts: audio tracks of the next age

From: http://baike.baidu.com/view/3393911.html? Fromtaglist # sub3393911

It is mentioned in this article that audio tracks of these times can be directly transmitted to the power amplifier through HDMI for decoding and output.

 

Introduction

Next-generation HD audio tracks, simply put, are the following five specifications: lpcm (lossless compression), Dolby Digital plus (lossy compression), Dolby truehd (lossless compression) DTS-HD high resolution (lossy compression), DTS-HD master audio (lossless compression ). These five audio tracks are all in the new audio track format on the CD. Compared with next-generation audio tracks, normal audio tracks have obvious differences in sound quality, just like MP3 with a 256kbps bit rate and lossless FLAC and ape with CD compression.

The best way to enjoy these audio tracks is to use HDMI to output the source code to the power amplifier, Which is decoded by the next-generation power amplifier. Output source code requires several conditions: 1. the player has HDMI 1.3 interface (dubi truehd, DTS-HD master audio these two lossless compression formats required); 2. Player software support.

At present, the remux source on the network already carries these next-generation HD audio tracks, so whether the player can provide the source code output function becomes an important performance benchmark.

Multi-channel lpcm: the original format of lossless audio tracks. It is equivalent to a wave file and does not require decoding. You can directly input a Power Amplifier for DA conversion. Because of the large bit rate and volume, in the DVD era, audio tracks are usually used in two-channel music discs. When the Blu-ray disc is used, the transmission rate and capacity increase dramatically, giving the opportunity to perform multi-channel lpcm audio tracks. Describes the specifications of the lpcm audio track, including the sampling frequency, sampling accuracy, and number of audio channels. The sampling frequency includes 48 khz, 96 kHz, and 192 kHz. The higher the frequency, the stronger the ability to restore high-frequency signals and rich harmonic waves, the sampling accuracy includes 16-bit and 24-bit. The higher the precision, the higher the signal-to-noise ratio, and the wider the dynamic range. However, for 96 k24bit 7.1 audio channels, the lpcm bit rate is about 18 Mbps, which will greatly occupy the video transmission bandwidth. Therefore, high-specification lossless audio tracks still require lossless compression encoding.

Edit category

The optical fiber and coaxial interfaces can only transmit 2-channel lpcm, while the multi-channel lcpm requires HDMI interface transmission. Even in HDMI 1.0, many first-generation HDMI interface amplifiers can receive the multi-channel lpcm audio signal.

In addition to the highest non-destructive audio tracks, the two companies also introduced lossy compression audio tracks, Dolby Digital plus and dts hd high resolution audio, the former can be referred to as DD + or eac3, in Blu-ray discs, the maximum bit rate is 1.7 Mbps. The latter can be referred to as dts hd hr. In Blu-ray discs, the maximum bit rate is 6 Mbps. Both of them can achieve 7.1-channel surround sound effects. Dd + seems to be born for HD DVDs, because it can have a maximum bit rate of 6 Mbps in HD DVDs, while dts hd hr is the opposite, with a maximum of 3 Mbps, with the demise of HD DVDs, DD + is basically invisible to Blu-ray discs, and only a demo Disc Made by Dolby itself. Dts hd hr is not much, because the bandwidth and space saved by DTs HD seem to be less attractive, and publishers seem reluctant to lose customers by using lossy compression audio tracks. These two kinds of lossy compression audio tracks also contain AC3 or DTS core data, and also have downward compatibility.

The above four new audio specifications require an HDMI 1.3 or above interface for source code bitstream transmission, which is the use of Asus xonar hdav 1.3.

Aside from two kinds of lossy compression audio tracks, which of the following is better? Since we all claim that it is a lossless audio track, compression or not will not affect the sound quality. It is determined that the bit rate has failed because these new compressed audio tracks are all compressed at a variable bit rate, the same as the 5.1-channel sample of 16-bit 48 kHz, the lpcm bit rate is 4.5 m, while the true HD and dts hd are often between 1.5-M. For most Blu-ray discs, they are more willing to use compressed audio tracks, after all, it can save transmission bandwidth to improve image quality, or use the precision of 24bit96khz under the same conditions.

Dolby truehd

Dolby truehd (Dolby truehd) Audio Encoding

100% lossless coding technology. The bit rate is up to 18 Mbps. Supports up to eight separate 24-bit/96 kHz full-band channels. * Supported by the HD media interface (HDMI. Supports various metadata functions, including white-to-white and dynamic range control. Dolby truehd supports more than eight channels.

Dolby Digital PLU

Dolby Digital plus (Dolby Digital plus) Audio Encoding

Multi-channel surround sound output by a separate channel. Number of audio channels and number of programs-you can process audio programs with up to 7.1 channels * and support carrying multiple programs in an encoded bit stream. Ability to output the Dolby Digital bit stream and play it on the existing Dolby Digital System.

The maximum bit rate is 6 Mbps. In an hd dvd, the bit rate is at least 3 Mbps, and in a Blu-ray disc, the bit rate is up to 1.7 Mbps. Accurately reproduce the sound effects carefully designed by directors and producers. Provides interactive sound mixing and streaming media transmission for high-end audio systems. Get the support of HDMI.