Post: Analysis of similarities and differences between multi-channel lpcm true HD DTS HD

From: http://blog.jianghu.taobao.com/u/NzkzMzk1Mzg=/blog/blog_detail.htm? Aid = 26948139.

 

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.

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.

Dolby true HD is a lossless compression audio track format developed by Dolby for HD Audio discs. It supports up to eight fully-band channels of up to 24 BIT/96 kHz separation, the maximum bit rate in a Blu-ray disc is 18 Mbps. Dolby claims that "True HD" is 100% lossless audio. Therefore, in addition to more bandwidth savings than the lcpm of the same specification, it can also be added to white talk and overall volume control to implement functions such as night cinema, its kernel also has an AC3 5.1 audio track data with a 5.1 K bit rate. Even if the entire video only has a true HD audio track, the old power amplifier can achieve sound effects through fiber transmission. In fact, from the structure analysis, true HD is the combination of MLP audio track data and ac3. MLP is the audio track encoding format of the DVD-audio.

The dts hd master audio in dts hd is the lossless compression audio track. DTS claims that it is a "bit for bit" full reproduction of the recording mother band effect and is also completely lossless compression, the maximum bit rate of a Blu-ray disc is 24.5 Mbps. Dts hd kernel also has 5.1 Mbps bit rate DTS 5.1 audio track data, so it can also transmit audio to the old power amplifier through spdif.

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.

 

 

Core and extended data

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. DTS and Dolby seem to be on the same starting line this time. As for the difference in the highest bit rate, I don't know how many people can tell, but there will be a debate in the future, I will not comment on it.