A Guide to Home Theater Audio CODECs

[Big Daddy]

Originally Posted by Headphone Czar

I was told optical/Coax does support LPCM but only over 2 channels?

You are correct. Read the post carefully and you will see the following statement under LPCM section:

"Cables Needed: Toslink (Optical) or Coaxial S/PDIF cannot carry a 5.1 LPCM signal, so the signal will be reduced to 2 channels only. However, any version of HDMI connection can carry the LPCM signal in full quality. Multi-Channel Analog Cables can also be used (see footnote)."

Did I misunderstand your statement?

[Kilian]

Originally Posted by Big Daddy

COMPARISON OF DOLBY DIGITAL AND DTS DIGITAL
...DTS can be encoded in 754Kbps (the most commonly used), or a maximum rate of 1.5Mbps (very seldom seen)...

The DTS HD Whitepaper cites the figure of 768kbps repeatedly; so both 754 and 768kbps are used?

Originally Posted by Big Daddy

THE IMPLICATIONS OF DIGITAL BITSTREAMING ON AUDIO IN BONUS VIEW FEATURES
...
Any secondary content, like menu beeps or the audio that accompanies Picture-in-Picture interactive features is not part of the original bitstream and will not be transmitted. Audio commentaries and alternative-language audio may also be affected, depending on how the disc was authored. The only way to send the additional content is by allowing the disc player to perform the audio decoding itself, during which the player mixes the new material on top of the movie soundtrack for transmission in either PCM or analog format....

The Panasonic DMP-BD30 outputs Dolby Digital to HDMI and S/PDIF when "bitstream" is selected and "BD-Video Secondary Audio" is set to "On" (manual, p.21).

[Stephan.klose]

Great Report. Only one small error.

Dolby Digital Plus was also mandatory for HD-DVD. Same as True HD.

I found that was a great move on behalf of the DVD forum that created the format. How much happier would all blu ray customers be if they realized before buying their player that not all of them can really decode the HD sound formats

[Silencer]

Originally Posted by Big Daddy

Your bandwidth statement is only correct about SACD and DVD-A. However, it is not correct about Lossless Audio Codecs such as LPCM, Dolby TrueHD, and DTS MA.

According to Toshiba, the inventor of Toslink (Toshiba Link), the maximum bandwith of an enhanced Toslink cable is around 6Mbs. LPCM, Dolby TrueHD, and DTS HD MA require more than that. HDMI's bandwidth is around 37Mbs. In addition, Toslink has a length limitation. I believe it is around 5 meters.

This is a quote from Wikipedia:

"Connecting a TrueHD source to a TrueHD receiver requires a digital-link capable of transporting either the encoded bitstream (up to 18 Mbit/s), or the unpacked linear-PCM audio (>35 Mbit/s). HDMI 1.1 (and higher) can transport multichannel PCM-audio, and therefore can transport an unpacked TrueHD audiotrack. An HDMI 1.3 (or higher) link is required to transport TrueHD in raw bitstream form. TOSLINK (and SPDIF) cannot carry TrueHD without transcoding, due to limitations of the specification."

http://en.wikipedia.org/wiki/Dolby_TrueHD

Hi !

I am a little bit disappointed by the Wikipedia quote regarding the HDMI version required to carry unpacked TrueHD and raw bitstream. Unpacked TrueHD is equivalent to LPCM right ? And thus has higher bitrate than raw bitstream which in compressed... so why raw bitstream is requiring HDMI 1.3.
Now I've got an additional question : are HD-non fitted receiver capable of playing TrueHD or DDPlus through HDMI 1.3 connection with some HD-decoding fitted players ?

Thank you in advance.

- Stéphane B.

[Silencer]

Originally Posted by Big Daddy

Your bandwidth statement is only correct about SACD and DVD-A. However, it is not correct about Lossless Audio Codecs such as LPCM, Dolby TrueHD, and DTS MA.

According to Toshiba, the inventor of Toslink (Toshiba Link), the maximum bandwith of an enhanced Toslink cable is around 6Mbs. LPCM, Dolby TrueHD, and DTS HD MA require more than that. HDMI's bandwidth is around 37Mbs. In addition, Toslink has a length limitation. I believe it is around 5 meters.

This is a quote from Wikipedia:

"Connecting a TrueHD source to a TrueHD receiver requires a digital-link capable of transporting either the encoded bitstream (up to 18 Mbit/s), or the unpacked linear-PCM audio (>35 Mbit/s). HDMI 1.1 (and higher) can transport multichannel PCM-audio, and therefore can transport an unpacked TrueHD audiotrack. An HDMI 1.3 (or higher) link is required to transport TrueHD in raw bitstream form. TOSLINK (and SPDIF) cannot carry TrueHD without transcoding, due to limitations of the specification."

http://en.wikipedia.org/wiki/Dolby_TrueHD

Hi !

I am a little bit disappointed by the Wikipedia quote regarding the HDMI version required to carry unpacked TrueHD and raw bitstream. Unpacked TrueHD is equivalent to LPCM right ? And thus has higher bitrate than raw bitstream which in compressed... so why raw bitstream is requiring HDMI 1.3.
Now I've got an additional question : are HD-non fitted receiver capable of playing TrueHD or DDPlus through HDMI 1.3 connection with some HD-decoding fitted players ?

Thank you in advance.

- Stéphane B.

[crackinhedz]

Originally Posted by Silencer

Unpacked TrueHD is equivalent to LPCM right ? And thus has higher bitrate than raw bitstream which in compressed... so why raw bitstream is requiring HDMI 1.3.

Bitstream of Dolby TrueHD and Dts-HD MA has nothing to do with the size of the information being sent, rather the capability of the actual HDMI chip itself.

Past hdmi chips (1.0, 1.1, 1.2a etc) did not have this ability...which is why HDMI v1.3 (chip) is required.

[Big Daddy]

Originally Posted by Silencer

Hi !

I am a little bit disappointed by the Wikipedia quote regarding the HDMI version required to carry unpacked TrueHD and raw bitstream. Unpacked TrueHD is equivalent to LPCM right ? And thus has higher bitrate than raw bitstream which in compressed... so why raw bitstream is requiring HDMI 1.3.
Now I've got an additional question : are HD-non fitted receiver capable of playing TrueHD or DDPlus through HDMI 1.3 connection with some HD-decoding fitted players ?

Thank you in advance.

- Stéphane B.

This is a quote from HighDef Digest.

“Think of Dolby TrueHD and DTS-HD MA as zipping a computer file to save space. None of the data is discarded, just packed more efficiently to take up less storage space. When you unzip the file, 100% of the data is still there, and you get a bit-for-bit copy of the original.

If you had a zipped document that you wanted to send me on disc, you would have two choices. You could unzip it on your computer before putting it on the disc. Or you could send it to me as a zipped file (would take up less space on the disc) and I could unzip it on my computer. Either way, I end up with the exact same document, down to the last letter.

Going back to the zipped document analogy. If you wanted to change anything in the document, from simple correction of spelling mistakes to complex re-formatting for a better look, you would first need to unzip that document. You wouldn't be able to manipulate it while it was still zipped.

Similarly, everything a receiver does to the soundtrack, up to and including D/A conversion, requires the soundtrack to be in uncompressed PCM form. In fact, when you send your receiver a DD or DTS bitstream, the first thing it does is decompress the soundtrack to linear PCM. Only then can it apply things like bass management, time alignment, etc.”


HDMI 1.0, 1.1, 1.2 had a maximum bit rate of 165MHz (4.9Gbps). HDMI 1.3 increased its bandwidth to 340 MHz (10.2 Gbps). However, as Crackinhedz mentioned, this has nothing to do with carrying bitstream signals.

HDMI 1.3 allows the zipped file (HD audio in compressed form) to be sent to the receiver. This is what is meant by sending the audio to the receiver in bitstream. HDMI 1.0, 1.1, and 1.2 could not do this. The HDMI 1.3 transmitter chip (SiI9134) was modified to do this. Sony PS3 uses the older HDMI 1.3 chip (SiI9132). That is the reason it cannot bitstream the HD audio signal. Is this a big advantage? Probably not as most players do a very good job of converting HD Audio to LPCM.

Silicon Image does not release any information about the SiI9132 chip used in PS3.

[Silencer]

Originally Posted by Big Daddy

This is a quote from HighDef Digest.

“Think of Dolby TrueHD and DTS-HD MA as zipping a computer file to save space. None of the data is discarded, just packed more efficiently to take up less storage space. When you unzip the file, 100% of the data is still there, and you get a bit-for-bit copy of the original.

If you had a zipped document that you wanted to send me on disc, you would have two choices. You could unzip it on your computer before putting it on the disc. Or you could send it to me as a zipped file (would take up less space on the disc) and I could unzip it on my computer. Either way, I end up with the exact same document, down to the last letter.

Going back to the zipped document analogy. If you wanted to change anything in the document, from simple correction of spelling mistakes to complex re-formatting for a better look, you would first need to unzip that document. You wouldn't be able to manipulate it while it was still zipped.

Similarly, everything a receiver does to the soundtrack, up to and including D/A conversion, requires the soundtrack to be in uncompressed PCM form. In fact, when you send your receiver a DD or DTS bitstream, the first thing it does is decompress the soundtrack to linear PCM. Only then can it apply things like bass management, time alignment, etc.”


HDMI 1.0, 1.1, 1.2 had a maximum bit rate of 165MHz (4.9Gbps). HDMI 1.3 increased its bandwidth to 340 MHz (10.2 Gbps). However, as Crackinhedz mentioned, this has nothing to do with carrying bitstream signals.

HDMI 1.3 allows the zipped file (HD audio in compressed form) to be sent to the receiver. This is what is meant by sending the audio to the receiver in bitstream. HDMI 1.0, 1.1, and 1.2 could not do this. The HDMI 1.3 transmitter chip (SiI9134) was modified to do this. Sony PS3 uses the older HDMI 1.3 chip (SiI9132). That is the reason it cannot bitstream the HD audio signal. Is this a big advantage? Probably not as most players do a very good job of converting HD Audio to LPCM.

Silicon Image does not release any information about the SiI9132 chip used in PS3.

All right, got it ! Thank you...

- STeF

[Sweeney Todd]

When compact disc players came about at 1985, experts said that this is the best possible sound human ear can hear. That was big lie of course, everyone knows nowadays.
Now we have 3 different lossless ways to have our blu-ray discs audio.
PCM, True-HD and DTS-MA. What do you think..? Isn´t it same that 1985, that experts say all three are perfect, but 2 of them are not, because True-HD and DTS-MA are not "lossless" because of compression??
I have couple of blu-ray discs and I have to say that Tim Burton´s Big Fish movie with pcm sounds perfect (limitless). With true-HD blu-ray I don´t have same feeling. DTS-MA souds bit better to me, but not same as PCM.
I´m professional musician, so I hear very small differenses in sound quality easily.
I´m not saying that I´m right or anything like that, but still again I want to ask anyone who got better knowledge:
Is it possible, that only PCM is perfect and others just almost?

[n9949y]

Before I buy any Blu-Ray 2.0 Profile aka BD-Live player, I'm wondering how using a new player's 5.1 or 7.1 analog audio outputs would work w/my system. My reveiver's a Rotel RX-965, vintage 2000, equipped with a DB25 5.1channel audio input. Appears the Rotel was designed to utilize SACD (Super-Audio CD) when that format was considered to have been the last and greatest.

I recently picked up a 6 jack RCA to DB25 cable; the RCA's are labled: Right, Left, Rt surround, Left surround , Center, and Subwoofer-standard 5.1 set up.

When I do buy a Blu-Ray player with 5.1 or 7.1 analog outputs, would connecting them to the receiver's DB25 cable 5.1 audio inputs work so I can receive Dolby TrueHD or DTS MA?

[Big Daddy]

Originally Posted by n9949y

Before I buy any Blu-Ray 2.0 Profile aka BD-Live player, I'm wondering how using a new player's 5.1 or 7.1 analog audio outputs would work w/my system. My reveiver's a Rotel RX-965, vintage 2000, equipped with a DB25 5.1channel audio input. Appears the Rotel was designed to utilize SACD (Super-Audio CD) when that format was considered to have been the last and greatest.

I recently picked up a 6 jack RCA to DB25 cable; the RCA's are labled: Right, Left, Rt surround, Left surround , Center, and Subwoofer-standard 5.1 set up.

When I do buy a Blu-Ray player with 5.1 or 7.1 analog outputs, would connecting them to the receiver's DB25 cable 5.1 audio inputs work so I can receive Dolby TrueHD or DTS MA?

I don't know a lot about your receiver. However, if it can handle analog SACD and DVD-A, my guess is that you will get the new HD audio codecs through multi-channel analog input. It is important that you consider the following:
1. Make sure the BD player decodes the new codecs to PCM.
2. You may have to do bass management in the BD player's menu.
3. Your Receiver does not have HDMI or Component video input/output. Therefore, you need to connect the BD player directly to a TV with component or HDMI input to take advantage of 720p, 1080i or 1080p.
4. Since your BD player is connected to the TV directly, you will have to do input switching manually.
5. Since your audio comes from the receiver and your video comes directly from the BD player, you may have a bit of lip sync problem. I am not sure how much of that you can fix with your receiver.

I hope this helps. I invite others to correct me or add anything else that I may have missed.

[n9949y]

Originally Posted by Big Daddy

....consider the following:
1. Make sure the BD player decodes the new codecs to PCM.
2. You may have to do bass management in the BD player's menu.
3. Your Receiver does not have HDMI or Component video input/output. Therefore, you need to connect the BD player directly to a TV with component or HDMI input to take advantage of 720p, 1080i or 1080p.....
5. Since your audio comes from the receiver and your video comes directly from the BD player, you may have a bit of lip sync problem.

Thanks, Bigdaddy, for the pointers. I intend to purchase a BD player such as the Panasonic DMP-BD-50 or 55 or equivalent w/onboard decoding.

Presently the Rotel RSX-965 is connected to my Progressive Onkyo DV-CP702 DVD player with a AC-3/PCM digital optical cable, and the LG RU-44SZ63D Monitor is connected to the DVD player with a component video cable. Never have had a lip sync problem.

Receiver- Rotel RSX 965
TV Monitor, DLP, LG RU-44SZ63D
Laser Disc Player- Pioneer CLD 1080
Field Sound Processor- Yamaha DSP E300
Comcast Cable- Motorola DCT6200
Tape Deck- Kenwood Double KX-W5040
DVD Player, Hi Def-Progressive - Onkyo DV-CP702
Graphic Equalizer- Pioneer GR-555
CD Player- Fisher DAC 195
VCR, Hi-Fi - Panasonic PV-4021
VCR, Hi-Fi- JVC SQPB
Turntable/Changer- Garrard Zero 100
Sub Woofers, 2 –Yamaha, powered YST-SW100 & YST WS-205
Speakers, 4, Paradigm Titan (2 for Rotel main fronts, 2 for Yamaha DSP front effects)
Speakers, 2 Dynaco A25 (Rotel rear effects)
Speakers, 2 Acoustic Research 18S, (Yamaha rear effects)
Speakers, 2 Realistic Minimus 7W ( Yamaha DSP Center, Rotel Center)
AC Voltage Activated Outlet Switch, Niles AC-3
Head phones, Sennheiser HD280 Pro

[Sweeney Todd]

Ahoj!
Is PCM and LPCM same thing? I mean if it is written on blu-ray cover, that there´s PCM 5.1 sound, does it in every case mean that audio is uncomprerssed and identical to 5.1 original master tape of the movie? Is there any change that PCM written on blu-ray´s cover, means something else than 100% uncompressed? Quite often this word uncompressed is missing from the cover notes. I think that for many blu-ray noobies like me, it would be easier, if it was written down.

[Big Daddy]

Originally Posted by Sweeney Todd

Ahoj!
Is PCM and LPCM same thing? I mean if it is written on blu-ray cover, that there´s PCM 5.1 sound, does it in every case mean that audio is uncomprerssed and identical to 5.1 original master tape of the movie? Is there any change that PCM written on blu-ray´s cover, means something else than 100% uncompressed? Quite often this word uncompressed is missing from the cover notes. I think that for many blu-ray noobies like me, it would be easier, if it was written down.

Yes, LPCM and PCM stand for the same thing. By defenition, PCM is the uncompressed translation of analog sound to digital. Therefore, it is redundant to write on the covers that the PCM is uncompressed. Read the section under the heading A BRIEF INTRODUCTION TO PCM, LOSSY, AND COMPRESSED LOSSLESS AUDIO in the OP.

"The audio on a Blu-Ray or HD-DVD disc is stored in either uncompressed linear Pulse Code Modulation (PCM), the compressed and lossless Dolby TrueHD, the compressed and lossless DTS Master Audio, the compressed and lossy Dolby Digital, the compressed and lossy DTS Digital algorithms, or combination of the above.

PCM is a procedure to represent an analog signal in digital form. Its accuracy is dependent upon the Sampling Rate and Sample Size."

[Brandon B]

Originally Posted by Big Daddy

Your bandwidth statement is only correct about SACD and DVD-A. However, it is not correct about Lossless Audio Codecs such as LPCM, Dolby TrueHD, and DTS MA.

Since DVD-A and (essentially) SACD can have the same lossless high bit rate mch audio requirements as DD THD and DTS-MA, how is it correct that the bandwidth limitation applies to BD audio tracks but not hirez audio discs?

DVD-A can have 5.1 mix of 24 bit 96Khz uncompressed audio on it, which requires almost 14Mbps (unless the .1 track is limited somehow, I don't know), and 5.1 multichannel SACD almost 17Mbps.

Just curious what I am missing. It seems to me the bandwidth limitation is the reason why none of these formats in playable through toslink.

[Big Daddy]

Originally Posted by Brandon B

Since DVD-A and (essentially) SACD can have the same lossless high bit rate mch audio requirements as DD THD and DTS-MA, how is it correct that the bandwidth limitation applies to BD audio tracks but not hirez audio discs?

DVD-A can have 5.1 mix of 24 bit 96Khz uncompressed audio on it, which requires almost 14Mbps (unless the .1 track is limited somehow, I don't know), and 5.1 multichannel SACD almost 17Mbps.

Just curious what I am missing. It seems to me the bandwidth limitation is the reason why none of these formats in playable through toslink.

That number you quoted is the maximum number for raw and uncompressed PCM signal.
96,000(samples per second) x 24(bits per sample) x 6(channels) = 13.8Mbps

1. PCM uses fixed bit rate. Dolby TrueHD and DTS HD MA use variable bit rates and on the average their bit rates are way below the 14Mbps.
2. As far as DVD-A is concerned, it is possible to get up to 96kHz/16bit or 48kHz/24bit in 5.1, and 192kHz/24bit in stereo. To store 5.1 tracks in 88.2kHz/20bit, 88.2kHz/24bit, 96kHz/20bit or 96kHz/24bit on a DVD disc, the use of Meridian Lossless Packing (MLP) compression is mandatory. MLP is the same technology used for compressing Dolby TrueHD signal.
3. SACD does not use PCM. It uses Direct Stream Digital (DSD). DSD is a different technology and is not directly comparable to PCM. It was developed by Sony/Philips.
4. The inability of Optical (Toslink) and Digital (S/PDIF) cables to carry HD audio is partly bandwidth limitation and partly copyright issue. I-Link (IEEE 1394) cable and Denon Link can carry DVD-A and SACD signals.
5. To get Dolby TrueHD, DTS HD, and PCM, you need HDMI or multichannel analog cables.

For additional information, read A Guide to DVD-A and Dualdisc and A Guide to SACD.

[UR_moms_Boytoy]

this is great info

[cranberry23]

I have a question which baffles me? My PS3 is hooked via HDMI 1.3 to my Yamaha 863. Settings are Linear PCM, and according to my PS3, I'm hearing TRUEHD. I was told if I select Bitstream, the Y863 will do the encoding and the TRUEHD light will indicate this, but it doesn't?

Any idea why? BTW, the TRUEHD sounds flat and dull unlike DTS which tears the paint of my walls. I have to ramp up the volume an extra 30dbls compared to DTS on my normal DVD player. There has to be a setting I'm overlooking on my AMP or maybe it's the PS3.

[prerich]

Originally Posted by cranberry23

I have a question which baffles me? My PS3 is hooked via HDMI 1.3 to my Yamaha 863. Settings are Linear PCM, and according to my PS3, I'm hearing TRUEHD. I was told if I select Bitstream, the Y863 will do the encoding and the TRUEHD light will indicate this, but it doesn't?

Any idea why? BTW, the TRUEHD sounds flat and dull unlike DTS which tears the paint of my walls. I have to ramp up the volume an extra 30dbls compared to DTS on my normal DVD player. There has to be a setting I'm overlooking on my AMP or maybe it's the PS3.

Probrably the most quoted phrase around here...The PS3 can't Bitstream TrueHD or DTS-HD-Master and will never be able to do so. It decodes itself and sends the info to the receiver as LPCM. Unless you get a bitsteaming stand alone - you will never see those lights shine. But don't worry about it - you are hearing what you are supposed to.

[Big Daddy]

Originally Posted by cranberry23

I have a question which baffles me? My PS3 is hooked via HDMI 1.3 to my Yamaha 863. Settings are Linear PCM, and according to my PS3, I'm hearing TRUEHD. I was told if I select Bitstream, the Y863 will do the encoding and the TRUEHD light will indicate this, but it doesn't?

Any idea why? BTW, the TRUEHD sounds flat and dull unlike DTS which tears the paint of my walls. I have to ramp up the volume an extra 30dbls compared to DTS on my normal DVD player. There has to be a setting I'm overlooking on my AMP or maybe it's the PS3.

1. Make sure you set your PS3 to LPCM. PS3 cannot bitstream audio to a receiver. If you set it to bitstream, you will get the lossy audio codecs. Read the conclusions in the original post and also read posts #26 and #27.
2. Go to the Settings of your PS3.

• Select BD/DVD Settings.
• Go to BD/DVD Dynamic Range Control.
• Change it from Automatic to Off.

3. In your receiver's menu, change the Night Mode to Off and change the Dynamic Range Control to Off.
Dolby TrueHD should sound better and louder after these changes.