pcm vs dolby vs dts: what's the difference between pcm and dolby adn dts?
pcm and dolby and dts are all signal formats.
Below are several Dolby Digital formats that may appear on DVD, let us explain them one by one:
1. Dolby Digital Mono: Dolby Digital Mono sound has only mono effects, which is not enough to form stereo. Most of it appears in older movies. When the movie is made, the mono sound will be stored as AC -3 format, so when it is decoded and played in the Dolby Digital system, only the middle channel sounds. This kind of sound quality performance is undoubtedly more boring, because even the basic three-dimensional sense is very lacking, let alone the surround effect.
2. Dolby Digital Stereo: Dolby Digital two-channel audio saves the two-channel stereo signal in AC-3 format, so when it is decoded and played in the Dolby Digital system, it can sound from the left and right channel speakers of the main channel . This is actually quite close to our common two-channel system (this is the case for general audio), which can construct a three-dimensional sound field, but the sound of Dolby Digital is compressed, which has some influence on the sound quality. , And CD records are not compressed and have the potential for high sound quality.
3. Dobly Digital Surround: Dolby Digital Surround Sound uses matrix coding technology to squeeze the main channel, center channel and rear surround channel into two channels, and store them in AC-3 format. When the Dolby Digital system is decoded and played, you can hear the complete five-channel sound, but the surround channel is a single sound effect, not stereo. There are not only four speakers, how can it be five-channel sound? That's because the surround channels at the rear of the general home theater system are dual-channel, here is to present a single sound with dual-channel, that is, let the two speakers emit exactly the same sound.
4. Dolby Digital 4.0: Dolby Digital Surround Sound 4.0 encodes four independent channels, including the main channel, center channel, and surround channel into AC-3 format and saves them to DVD movies. Therefore, through Dolby Digital When the system is decoded and played, you can hear a complete five-channel. At this time, the surround channel is an independent mono recording. At first glance, Dolby Digital Surround and Dolby Digital 4.0 seem to be the same, but it is not. Strictly speaking Now, Dolby Digital Surround uses two channels to store data. The middle channel and surround channels are derived and calculated from these two channels; however, Dolby Digital 4.0 uses four sound channels. The main channel, center channel, and surround channel are stored in the main channel, and there are still some differences.
5. Dolby Digital 5.0: Dolby Digital Surround Sound 5.0 encodes five independent channels, including the main channel, center channel, and rear channel into AC-3 format and saves them to DVD movies. When the system decodes and plays, it can restore the complete five-channel. At this time, the rear surround channels start to take the independent two-channel route, providing a more precise sense of positioning and sound field surround.
6. Dolby Digital 5.1: In addition to the main channel, center channel and back channel, Dolby Digital 5.1 surround sound effect adds a subwoofer channel, and then encodes these six channels into AC-3 format for storage. Therefore, when playing with Dolby Digital system decoding, you can hear five channels plus a subwoofer channel. Since this bass channel only covers the low frequency range, not the complete frequency range, it is taken as 0.1. To remind readers, not all DVD movies provide bass channel sound effects. Therefore, if the low frequency of your main channel speaker is heavy enough, it can actually extend the low frequency effect. It is not necessary to add this subwoofer. Although Dolby Digital has many possibilities, including different output channels, but generally speaking, we simply use Dolby Digital to represent Dolby Digital 5.1, which is 5.1 channel Dolby Digital or AC-3. As for the two-channel Dolby Digital 2.0, it will probably be called 2 Channel Dolby Digital.
Dolby Digital 5.1 can compress the same data less and occupy the smallest space. Conversely, because DTS does not deliberately pursue the strongest compression capabilities, it also has the opportunity to save more information. If handled properly, it can indeed provide a lot of Superior performance.
Encoding method Dolby Digital (Dolby AC-3) Dolby Pro Logic DTS
Processing method Independent digital coding for each channel Analog matrix calculation Independent digital coding for each channel
Number of recording channels* 5.1 channels 2 channels 5.1 channels
Number of playback channels 5.1ch 4ch 5.1ch
Whether the surround channel is stereo stereo mono stereo
Surround channel bandwidth 20Hz~20KHz 100Hz~7KHz 20Hz~20KHz
Independent subwoofer channel Yes No Yes
Transmission rate 448kbps** N/A 1536kbps
Note: * indicates the number of channels that need to be occupied during recording (Channel). For example, although Dolby Prologic belongs to a four-channel surround system,
But in fact, the center channel and the surround channel can be hidden in two channels by matrix calculation (Matrix), so only two channels are used for storage.
**This is an average value on a general DVD, but the actual transfer rate is subject to change.
DTS
Dolby Digital stores the sound effect data in the middle of the perforations on the film. Due to space limitations, a large number of compression modes must be used, so it also sacrifices part of the sound quality.
However, this limitation was solved by a small company, DTS, which was originally silent. The method is to put the sound effect data on another CD-ROM and synchronize it with the image. With the increase of space, the data traffic can also be relatively larger. It is also possible to replace the CD that plays the sound effect data, and you can play other language versions. It is really convenient for movie theaters, and because of this, DTS is in professional theaters. Beats Dolby
In the LD era, due to the limitations of LD's inherent specifications, it is not compatible with 5.1 channel Dolby
AC-3 and DTS, it can be said that the fish and the bear's paw cannot have both, which also caused the failure of DTS in the home theater market. In the current DVD era, because the large capacity of DVD can be compatible with AC-3 and DTS on a single video disc , But because of some non-technical issues, DTS must use the PES format that is incompatible with the previous PCM format. Although the digital output connector is the same, the old DVDPLAYER cannot recognize the PES format, so I want to use DTS. Audio users must change to a new generation of models to use DTS, which undoubtedly hinders the route of DTS.
The difference between DTS and AC-3 is the size of the data traffic. DTS has 1536Kbps of data traffic on DVD. Compared with 384Kbps~448Kbps, it is more than 3 times the data traffic, even if AC-3 is pulled to the limit. At 640Kbps, DTS is still more than 2 times stronger than AC-3, which allows DTS to hear more details than AC-3, and the overall sense of space and movement will be better and clearer.
DTS ES Discrete 6.1
When most AV fans did not have a 6.1 or 7.1 channel system, DTS officially announced the launch of a new 6.1 channel system on June 15, 2000.
This new system is called DTS ES Discrete 6.1. What does Discrete mean? It means separation and independence.
This means that DTS ES Discrete 6.1
That is, the surround back is recorded in an independent audio track (in fact, an independent extension area is added to the 5.1-channel core area of the master tape),
There is no need to mix the left and right surround channels through matrix encoding.
Since there is no matrix encoding, of course, there is no need to separate the decoding from the left and right surround channels. In fact, the 5.1 channels we are currently using are independent of each channel.
There is no mutual mixing. It's just for the "expedient" surround back channel, the old method of matrix mixing in the past was used to process the back surround channel. According to Lorr of DTS
Kramer (Director of Spacial Technical Projects) said,
They originally thought that it was not appropriate to insert the surround back channels into the left and right surround channels using a matrix method, so they had long wanted to treat the surround back channels as independent channels.
And this is not technically difficult.
In addition, the electronic movie E-Cinema (or Digital Cinema) that will be played in the cinema has been determined to use an independent surround back channel,
The share of the DTS system in movie theaters is no less than that of the Dolby system, so an independent rear surround system will definitely be used in movie theaters. In that case,
DTS simply decided to launch an independent surround back channel system in the home market, which is the DTS ES Discrete 6.1 system.
Compare AC3 and DTS
AC3 (Dolby Digital Audio Code v3) and DTS (Digital Theater
Sound) These two cinema-level digital surround systems have been widely used in the sound coding of DVD video discs. It is also the most discussed topic among fans. Both are based on multi-channel encoding technology, universal 5.1 channels (three sets of full-range stereo)-left/right front, center/bass, left/right rear surround. Among them, the bass unit specially reproduces low frequencies below 120HZ to enhance the effect.
From the data flow point of view, AC3 is usually 384/448Kbps, using a high compression code (12:1), through the chief officer deletes the theoretically redundant detailed signals, so as to achieve the purpose of reducing the amount of data. In fact, AC3's coding technology is quite excellent, and it still brings a more realistic sound experience to the audience under such a low data traffic.
The data flow of DTS is usually 768/1536Kbps, and the compression ratio is only 3:1. It starts from improving the utilization of digital space to make full use of information data. Theoretically, its sound field is better than AC3 in terms of authenticity, delicacy, continuity, broadness and layering.
pcm and dolby and dts are all signal formats.
- These are the three common encodings for DVDs. The biggest differences between the three are as follows:
- pcm is generally lossless audio (cd sound quality), 2 channels (pcm5.1 is 5.1 channels).
- dts\dobly are generally 5.1 channels, which are smaller in capacity than pcm5.1 and higher cost performance
- Generally speaking, the surround effect dts is better. The sound quality pcm is better, and the dolby capacity is smaller.
- Simply put, pcm is 2 channels and dts\dobly is 5.1 channels. Can you understand this time.
Below are several Dolby Digital formats that may appear on DVD, let us explain them one by one:
1. Dolby Digital Mono: Dolby Digital Mono sound has only mono effects, which is not enough to form stereo. Most of it appears in older movies. When the movie is made, the mono sound will be stored as AC -3 format, so when it is decoded and played in the Dolby Digital system, only the middle channel sounds. This kind of sound quality performance is undoubtedly more boring, because even the basic three-dimensional sense is very lacking, let alone the surround effect.
2. Dolby Digital Stereo: Dolby Digital two-channel audio saves the two-channel stereo signal in AC-3 format, so when it is decoded and played in the Dolby Digital system, it can sound from the left and right channel speakers of the main channel . This is actually quite close to our common two-channel system (this is the case for general audio), which can construct a three-dimensional sound field, but the sound of Dolby Digital is compressed, which has some influence on the sound quality. , And CD records are not compressed and have the potential for high sound quality.
3. Dobly Digital Surround: Dolby Digital Surround Sound uses matrix coding technology to squeeze the main channel, center channel and rear surround channel into two channels, and store them in AC-3 format. When the Dolby Digital system is decoded and played, you can hear the complete five-channel sound, but the surround channel is a single sound effect, not stereo. There are not only four speakers, how can it be five-channel sound? That's because the surround channels at the rear of the general home theater system are dual-channel, here is to present a single sound with dual-channel, that is, let the two speakers emit exactly the same sound.
4. Dolby Digital 4.0: Dolby Digital Surround Sound 4.0 encodes four independent channels, including the main channel, center channel, and surround channel into AC-3 format and saves them to DVD movies. Therefore, through Dolby Digital When the system is decoded and played, you can hear a complete five-channel. At this time, the surround channel is an independent mono recording. At first glance, Dolby Digital Surround and Dolby Digital 4.0 seem to be the same, but it is not. Strictly speaking Now, Dolby Digital Surround uses two channels to store data. The middle channel and surround channels are derived and calculated from these two channels; however, Dolby Digital 4.0 uses four sound channels. The main channel, center channel, and surround channel are stored in the main channel, and there are still some differences.
5. Dolby Digital 5.0: Dolby Digital Surround Sound 5.0 encodes five independent channels, including the main channel, center channel, and rear channel into AC-3 format and saves them to DVD movies. When the system decodes and plays, it can restore the complete five-channel. At this time, the rear surround channels start to take the independent two-channel route, providing a more precise sense of positioning and sound field surround.
6. Dolby Digital 5.1: In addition to the main channel, center channel and back channel, Dolby Digital 5.1 surround sound effect adds a subwoofer channel, and then encodes these six channels into AC-3 format for storage. Therefore, when playing with Dolby Digital system decoding, you can hear five channels plus a subwoofer channel. Since this bass channel only covers the low frequency range, not the complete frequency range, it is taken as 0.1. To remind readers, not all DVD movies provide bass channel sound effects. Therefore, if the low frequency of your main channel speaker is heavy enough, it can actually extend the low frequency effect. It is not necessary to add this subwoofer. Although Dolby Digital has many possibilities, including different output channels, but generally speaking, we simply use Dolby Digital to represent Dolby Digital 5.1, which is 5.1 channel Dolby Digital or AC-3. As for the two-channel Dolby Digital 2.0, it will probably be called 2 Channel Dolby Digital.
Dolby Digital 5.1 can compress the same data less and occupy the smallest space. Conversely, because DTS does not deliberately pursue the strongest compression capabilities, it also has the opportunity to save more information. If handled properly, it can indeed provide a lot of Superior performance.
Encoding method Dolby Digital (Dolby AC-3) Dolby Pro Logic DTS
Processing method Independent digital coding for each channel Analog matrix calculation Independent digital coding for each channel
Number of recording channels* 5.1 channels 2 channels 5.1 channels
Number of playback channels 5.1ch 4ch 5.1ch
Whether the surround channel is stereo stereo mono stereo
Surround channel bandwidth 20Hz~20KHz 100Hz~7KHz 20Hz~20KHz
Independent subwoofer channel Yes No Yes
Transmission rate 448kbps** N/A 1536kbps
Note: * indicates the number of channels that need to be occupied during recording (Channel). For example, although Dolby Prologic belongs to a four-channel surround system,
But in fact, the center channel and the surround channel can be hidden in two channels by matrix calculation (Matrix), so only two channels are used for storage.
**This is an average value on a general DVD, but the actual transfer rate is subject to change.
DTS
Dolby Digital stores the sound effect data in the middle of the perforations on the film. Due to space limitations, a large number of compression modes must be used, so it also sacrifices part of the sound quality.
However, this limitation was solved by a small company, DTS, which was originally silent. The method is to put the sound effect data on another CD-ROM and synchronize it with the image. With the increase of space, the data traffic can also be relatively larger. It is also possible to replace the CD that plays the sound effect data, and you can play other language versions. It is really convenient for movie theaters, and because of this, DTS is in professional theaters. Beats Dolby
In the LD era, due to the limitations of LD's inherent specifications, it is not compatible with 5.1 channel Dolby
AC-3 and DTS, it can be said that the fish and the bear's paw cannot have both, which also caused the failure of DTS in the home theater market. In the current DVD era, because the large capacity of DVD can be compatible with AC-3 and DTS on a single video disc , But because of some non-technical issues, DTS must use the PES format that is incompatible with the previous PCM format. Although the digital output connector is the same, the old DVDPLAYER cannot recognize the PES format, so I want to use DTS. Audio users must change to a new generation of models to use DTS, which undoubtedly hinders the route of DTS.
The difference between DTS and AC-3 is the size of the data traffic. DTS has 1536Kbps of data traffic on DVD. Compared with 384Kbps~448Kbps, it is more than 3 times the data traffic, even if AC-3 is pulled to the limit. At 640Kbps, DTS is still more than 2 times stronger than AC-3, which allows DTS to hear more details than AC-3, and the overall sense of space and movement will be better and clearer.
DTS ES Discrete 6.1
When most AV fans did not have a 6.1 or 7.1 channel system, DTS officially announced the launch of a new 6.1 channel system on June 15, 2000.
This new system is called DTS ES Discrete 6.1. What does Discrete mean? It means separation and independence.
This means that DTS ES Discrete 6.1
That is, the surround back is recorded in an independent audio track (in fact, an independent extension area is added to the 5.1-channel core area of the master tape),
There is no need to mix the left and right surround channels through matrix encoding.
Since there is no matrix encoding, of course, there is no need to separate the decoding from the left and right surround channels. In fact, the 5.1 channels we are currently using are independent of each channel.
There is no mutual mixing. It's just for the "expedient" surround back channel, the old method of matrix mixing in the past was used to process the back surround channel. According to Lorr of DTS
Kramer (Director of Spacial Technical Projects) said,
They originally thought that it was not appropriate to insert the surround back channels into the left and right surround channels using a matrix method, so they had long wanted to treat the surround back channels as independent channels.
And this is not technically difficult.
In addition, the electronic movie E-Cinema (or Digital Cinema) that will be played in the cinema has been determined to use an independent surround back channel,
The share of the DTS system in movie theaters is no less than that of the Dolby system, so an independent rear surround system will definitely be used in movie theaters. In that case,
DTS simply decided to launch an independent surround back channel system in the home market, which is the DTS ES Discrete 6.1 system.
Compare AC3 and DTS
AC3 (Dolby Digital Audio Code v3) and DTS (Digital Theater
Sound) These two cinema-level digital surround systems have been widely used in the sound coding of DVD video discs. It is also the most discussed topic among fans. Both are based on multi-channel encoding technology, universal 5.1 channels (three sets of full-range stereo)-left/right front, center/bass, left/right rear surround. Among them, the bass unit specially reproduces low frequencies below 120HZ to enhance the effect.
From the data flow point of view, AC3 is usually 384/448Kbps, using a high compression code (12:1), through the chief officer deletes the theoretically redundant detailed signals, so as to achieve the purpose of reducing the amount of data. In fact, AC3's coding technology is quite excellent, and it still brings a more realistic sound experience to the audience under such a low data traffic.
The data flow of DTS is usually 768/1536Kbps, and the compression ratio is only 3:1. It starts from improving the utilization of digital space to make full use of information data. Theoretically, its sound field is better than AC3 in terms of authenticity, delicacy, continuity, broadness and layering.
