DTS output over SPDIF/RAW? even with no DTS logo?

[kujoe]

I swear I searched first, and didn't find anything on this. If there is a duplicate thread please merge!

Anyhow my question is this:

I have a Magnavox MDV455 DVD player (I know, I bought this before I knew how important it was to have a higher end DVD player). This dvd player has a coaxial digital output. However, this dvd player only has built in Dolby Digital. I can access the dolby digital settings from the DVD players menu, and there is no DTS setup options at all. Likewise there is no DTS logo on the dvd player.

However, I recently bought a NICE HT Receiver and speaker system, the receiver is a THX certified Yamaha receiver, (don't have the model off the top of my head) anyhow, it can decode dts and dolby digital formats. My question is, since the DVD player doesn't have a built in dts decoder, or seemingly offers absolutely no DTS support, is it possible for my receiver to still provide me with DTS sound by using the SPDIF/RAW signal from my dvd player??

Or am I basically out of luck and need to buy a new DVD player? If I do need to buy a new DVD player, any suggestions?

Thanks!

 

[jaxvon]

I'm not sure, but I'm leaning towards no. I think you need to have DTS support to even send it digitally. If you need a new player and don't want to drop a ton of cash, you might want to check out the Pioneer DV-588AS. If you shop around online, you can find it for around $120 and it will play basically any optical disc you throw into it (DVD, SACD, DiVx,WMA, MP3, CD, etc). It doesn't have the super nice picture quality of a higher end DVD player, but for the price, it has a plethora of features that, IMO, can't be beat.

 

[kujoe]

I'm not sure, but I'm leaning towards no. I think you need to have DTS support to even send it digitally. If you need a new player and don't want to drop a ton of cash, you might want to check out the Pioneer DV-588AS. If you shop around online, you can find it for around $120 and it will play basically any optical disc you throw into it (DVD, SACD, DiVx,WMA, MP3, CD, etc). It doesn't have the super nice picture quality of a higher end DVD player, but for the price, it has a plethora of features that, IMO, can't be beat.

Well, as I mentioned above, the receiver is capable of decoding it on it's own, so I don't think the DVD player has to have the decoder on it, but I want to make damn sure that it's possible for the receiver to decode the dts over the SPDIF/RAW signal over coax output.

I've read some places that say you can do it, and some that say it may not be possible, so I'm coming here to ask cuz of the conflicting reports. I would think if it's just a raw digital signal, and the receiver is capable of decoding it, it should be able to decode the dts over the signal, even though the DVD player isn't capable of decoding dts? Right? Wrong? Does anyone know for sure?

 

[jaxvon]

Why don't you pick up a digital coax cable and find out? That's an easy and cheap way to do it. If it sends a DTS signal, the receiver should recognize it and somehow indicate it is using DTS decoding.

http://www.partexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=181-626

 

[MDS]

If you are using a digital connection, the player isn't going to do anything but read the bits off the disc and send them out the digital out. Both DD and DTS are PCM formats so as long as the player is capable of outputting the bitstream it should work.

The catch is whether or not the player has a setting for 'raw' or 'bitstream' for any LPCM format. If the only place in the menu to set the output to raw is under the DD options, then it may not work. If it has a setting that says LPCM, set it to PCM and try it.

Just use any old composite video cable you have lying around to try it.

 

[kujoe]

If you are using a digital connection, the player isn't going to do anything but read the bits off the disc and send them out the digital out. Both DD and DTS are PCM formats so as long as the player is capable of outputting the bitstream it should work.

The catch is whether or not the player has a setting for 'raw' or 'bitstream' for any LPCM format. If the only place in the menu to set the output to raw is under the DD options, then it may not work. If it has a setting that says LPCM, set it to PCM and try it.

Just use any old composite video cable you have lying around to try it.

You can use a regular composite cable to connect to the coax?

The DVD player can output both PCM, or SPDIF/RAW for sure, and I believe this can be done without being in the Dolby Digital menu.

Also, I have PCM/96k and PCM/48k. What is the difference in the SPDIF/RAW and both PCMs? What is this PCM, anything I read up on PCM made it sound like it was only 2 channel stereo? Or can you actually send a full digital signal for all 7.1 channels over PCM? Or is SPDIF/RAW actually better for this?

Sorry if I seem like a stupid n00b, I'm new to this audiophile stuff, but am loving every second of it and definitely want to immerse myself into it more.

 

[MDS]

PCM is Pulse Code Modulation. It is the lowest common denominator in digital audio. Briefly, every sample in a digital audio file is a number that represents the amplitude of the original analog signal at a point in time. The number of samples per second is the sampling frequency. 48K or 96K refers to the 'bitrate' and means there are 48,000 (48K) or 96,000 (96K) samples for every second of audio. By contrast, audio on a CD is 16/44.1 kHz PCM - meaning there are 44,100 16 bit samples for every second of audio. You can have any number of channels stored as PCM - it's not just 2 channel stereo.

DD and DTS are lossy compression formats. The underlying audio is PCM. Although different algorithms, they are analogous to lossy compression formats like MP3, WMA, AAC, etc. The data is PCM but cannot played directly because it needs to be 'decoded' into raw PCM. When you set a player to 'bitstream' or 'raw', it tells the player to not try to determine what the format is and decode it - just send the bitstream to the other device.

S/PDIF is Sony/Philips Digital Interface Format. It defines the format of the data and the protocol for transporting it over the wire (coax) or optical cable. In other words, the audio data is packaged into S/PDIF frames. So if the player is set to 'bitstream' it will just read the data off the disc, package it into S/PDIF frames, and transmit it over the digital output to the receiver.

A digital coax cable has to be 75 Ohm impedance to meet the S/PDIF spec. All video cables meet that spec, so yes you can use any composite video cable as a digital audio cable.

 

[kujoe]

PCM is Pulse Code Modulation. It is the lowest common denominator in digital audio. Briefly, every sample in a digital audio file is a number that represents the amplitude of the original analog signal at a point in time. The number of samples per second is the sampling frequency. 48K or 96K refers to the 'bitrate' and means there are 48,000 (48K) or 96,000 (96K) samples for every second of audio. By contrast, audio on a CD is 16/44.1 kHz PCM - meaning there are 44,100 16 bit samples for every second of audio. You can have any number of channels stored as PCM - it's not just 2 channel stereo.

DD and DTS are lossy compression formats. The underlying audio is PCM. Although different algorithms, they are analogous to lossy compression formats like MP3, WMA, AAC, etc. The data is PCM but cannot played directly because it needs to be 'decoded' into raw PCM. When you set a player to 'bitstream' or 'raw', it tells the player to not try to determine what the format is and decode it - just send the bitstream to the other device.

S/PDIF is Sony/Philips Digital Interface Format. It defines the format of the data and the protocol for transporting it over the wire (coax) or optical cable. In other words, the audio data is packaged into S/PDIF frames. So if the player is set to 'bitstream' it will just read the data off the disc, package it into S/PDIF frames, and transmit it over the digital output to the receiver.

A digital coax cable has to be 75 Ohm impedance to meet the S/PDIF spec. All video cables meet that spec, so yes you can use any composite video cable as a digital audio cable.

Thank you very much. You have been VERY helpful. According to your post then I do not need a new DVD player as the raw signal can be decoded by my receiver. That is definitely good news to me.

Also, if you are able to use a regular composite video cable in place of a coaxial cable for the same connection, what is the benefit of using an actual coaxial cable versus a composite cable? Does it actually have an improvement in performance?

Once again thanks!

 

[MDS]

A composite video cable is a coaxial cable. A cable that is advertised as a 'digital audio' cable simply means that it meets the S/PDIF specs and is 75 ohm characteristic impedance. It just so happens that video cables are the same.

I can't guarantee that your player will work. It's always possible that it will try to identify the format first and then look at your settings to determine whether it should decode it itself or pass along the bitstream.

Try it and let us know if it worked.

 

[j_garcia]

You DO need a player that can read the DTS stream to send to the reciever. Depsite the fact that it is digital, not all players can read the stream off the disc.

 

[Buckle-meister]

PCM is Pulse Code Modulation. It is the lowest common denominator in digital audio. Briefly, every sample in a digital audio file is a number that represents the amplitude of the original analog signal at a point in time. The number of samples per second is the sampling frequency. 48K or 96K refers to the 'bitrate' and means there are 48,000 (48K) or 96,000 (96K) samples for every second of audio. By contrast, audio on a CD is 16/44.1 kHz PCM - meaning there are 44,100 16 bit samples for every second of audio. You can have any number of channels stored as PCM - it's not just 2 channel stereo.

DD and DTS are lossy compression formats. The underlying audio is PCM. Although different algorithms, they are analogous to lossy compression formats like MP3, WMA, AAC, etc. The data is PCM but cannot played directly because it needs to be 'decoded' into raw PCM. When you set a player to 'bitstream' or 'raw', it tells the player to not try to determine what the format is and decode it - just send the bitstream to the other device.

S/PDIF is Sony/Philips Digital Interface Format. It defines the format of the data and the protocol for transporting it over the wire (coax) or optical cable. In other words, the audio data is packaged into S/PDIF frames. So if the player is set to 'bitstream' it will just read the data off the disc, package it into S/PDIF frames, and transmit it over the digital output to the receiver.

A digital coax cable has to be 75 Ohm impedance to meet the S/PDIF spec. All video cables meet that spec, so yes you can use any composite video cable as a digital audio cable.

This is another cracker MDS. I have a couple of questions for you:

1. By bitstream, I presume we mean a continuous stream of 1's and 0's?

2. When the bitstream is packaged into S/PDIF frames, what does it 'look' like?

3. I am interested in the whole encode/decode/carrier process. Any articles or books you'd recommend for further reading?

Regards

 

[j_garcia]

Buckle, I found this for you: http://www.mtsu.edu/~dsmitche/rim420/materials/Interface.html

 

[3db]

I swear I searched first, and didn't find anything on this. If there is a duplicate thread please merge!

Anyhow my question is this:

I have a Magnavox MDV455 DVD player (I know, I bought this before I knew how important it was to have a higher end DVD player). This dvd player has a coaxial digital output. However, this dvd player only has built in Dolby Digital. I can access the dolby digital settings from the DVD players menu, and there is no DTS setup options at all. Likewise there is no DTS logo on the dvd player.

However, I recently bought a NICE HT Receiver and speaker system, the receiver is a THX certified Yamaha receiver, (don't have the model off the top of my head) anyhow, it can decode dts and dolby digital formats. My question is, since the DVD player doesn't have a built in dts decoder, or seemingly offers absolutely no DTS support, is it possible for my receiver to still provide me with DTS sound by using the SPDIF/RAW signal from my dvd player??

Or am I basically out of luck and need to buy a new DVD player? If I do need to buy a new DVD player, any suggestions?

Thanks!

A big resounding Yes to your question. I bought a cheapy Electrohome to tie me over until the universal DVD players with both SACD and DVD-A came down in price. It has no DTS decodin either so I output SPDIF/RAW signal to my Tecnhics receiver and it decodes it . The DTS light lights up on my receiver. Your Yamaha will do the same.

The RAW means unprocessed so its the receiver's job to interpret and decode accordingly.

 

[Buckle-meister]

...I found this for you...

Thanks. It started out ok, but got a bit heavy. A few more reads might help there though.

When the bitstream is packaged into S/PDIF frames, what does it 'look' like?

I've been thinking about this. S/PDIF must still just be a continuous stream of 1's and 0's, but the order/pattern of them defines the packaged format. True?

[S/PDIF] Audio format: linear 16 bit default, up to 24 bit expandable

Why, if up to 24 bits were available, as proven by:

Both S/PDIF and AES/EBU can, and do transfer 24 bit words. In AES/EBU, the last 4 bits have a defined usage, so if anyone puts audio in there, it has to go to something that doesn't expect [it]. But in S/PDIF, there's nothing that says what you have to use the bits for, so filling them all up with audio is acceptable.

...didn't the developers of CD use them (though I think I'm right in saying that HDCD's do use 20 (?) bits (why not 24?))? This would have allowed more accurate (though perhaps not noticably so) samples to be obtained would it not?

...things which can cause differences between the sound of digital interfaces: Jitter (clock phase noise). This really only affects sound of the signal going directly to a DAC. If you're running into a computer, the computer is effectively going to be reclocking everything. Same applies also to CD-recoders, DAT tape decs and similar devices. Even modern DACs have typically a small buffer and reclocking circuitry, so the jitter is not so big [the] problem nowadays that it used to be.

I believe that this article is pretty old, but why, if data is reclocked nowadays, isn't there zero jitter? Or is there?

The first 4 bits of a 32-bit word (bits 0 through 3) form a preamble which takes care of synchronisation. This sync-pattern doesn't actually carry any data, but only equals four databits in length. There are 3 different sync-patterns, but they can appear in different forms, depending on the last cell of the previous 32-bit word (parity):

B: Marks a word containing data for channel A (left) at the start of the data-block.

M: Marks a word with data for channel A that isn't at the start of the data-block.

W: Marks a word containing data for channel B. (right, for stereo). When using more than 2 channels, this could also be any other channel (except for A).

I don't get that last bit (no pun intended! ). My question was namely that for multi-channel recordings, wouldn't more 'synchronisation bits' be required therefore lowering the number of remaining bits available for music etc?

Regards

 

[kujoe]

Man, this is a really belated response. Sorry!

Anyhow for anyone that might happen across this thread again wondering the same question I had in my first post....

Yes, setting my dvd player to output the raw PCM signal straight to my receiver did indeed work for getting wonderful DTS pumping through my 7.1 speakers.

It seems the key here is, if your dvd player cannot decode DTS (but can output PCM), then you need to make sure your receiver can decode the DTS format.

This probably works for other formats too.

 

[MACCA350]

Man, this is a really belated response. Sorry!

Anyhow for anyone that might happen across this thread again wondering the same question I had in my first post....

Yes, setting my dvd player to output the raw PCM signal straight to my receiver did indeed work for getting wonderful DTS pumping through my 7.1 speakers.

It seems the key here is, if your dvd player cannot decode DTS (but can output PCM), then you need to make sure your receiver can decode the DTS format.

This probably works for other formats too.

You did mean RAW or Bitstream not PCM(this will tell your player to decode and output as PCM and your receiver wont get the raw DTS or DD bitstream)

cheers

 

[kujoe]

You did mean RAW or Bitstream not PCM(this will tell your player to decode and output as PCM and your receiver wont get the raw DTS or DD bitstream)

cheers

Err.. yeah.