An Attempt to Explain High Definition Audio

JUS

Well-known Member
I searched the thread and couldn't find this nugget of information...but I apologise if it's already been covered...

I learned the HDMI standards dictate that the audio bandwidth transmitted over hdmi is limited depending on the video. So transmit a sd video signal over hdmi and you'll get a sd audio signal. You can only get hd audio if you are transmitting 720p or higher.
 

dante01

Distinguished Member
I searched the thread and couldn't find this nugget of information...but I apologise if it's already been covered...

I learned the HDMI standards dictate that the audio bandwidth transmitted over hdmi is limited depending on the video. So transmit a sd video signal over hdmi and you'll get a sd audio signal. You can only get hd audio if you are transmitting 720p or higher.

It has nothing to do with the resolution of the video. You get HD audio if it is present and part ot of the encoded media you are playing, this is regardless of the video's resolution.

You can stream rhe audio without actually even having a video signal present.
 
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MADEINUK

Standard Member
It has nothing to do with the resolution of the video. You get HD audio if it is present and part ot of the encoded media you are playing, this is regardless of the video's resolution.

You can stream rhe audio without actually even having a video signal present.

I think this is part of the reason for confusion surrounding HD audio sound tracks. As Dante01 rightly points out there is no need for a video hook up if you want to access the HD audio present on BLU-RAY discs. But, the mis-understanding seems to be originating from sales staff at certain AV retail outlets! I've been into stores recently and 'overheard' the most horrendously inaccurate descriptions of what audio may be replayed via HDMI. The best of these involed replaying old VHS stereo through a PIONEER VSX 1018 and being able to "DECODE" a 7.1 sound track from it!?! Yes i know DDIIx & DTS NEO6 can simulate 7.1 audio but without a BLU-RAY or HD disc present it won't be HD audio.
 

MADEINUK

Standard Member
I think this is part of the reason for confusion surrounding HD audio sound tracks. As Dante01 rightly points out there is no need for a video hook up if you want to access the HD audio present on BLU-RAY discs. But, the mis-understanding seems to be originating from sales staff at certain AV retail outlets! I've been into stores recently and 'overheard' the most horrendously inaccurate descriptions of what audio may be replayed via HDMI. The best of these involed replaying old VHS stereo through a PIONEER VSX 1018 and being able to "DECODE" a 7.1 sound track from it!?! Yes i know DDIIx & DTS NEO6 can simulate 7.1 audio but without a BLU-RAY or HD disc present it won't be HD audio.

I know this entry is stating the obvious but I don't think the different terms used to describe HD audio, i.e. 'LOSSLESS' 'UN-COMPRESSED' etc.help the novice user to understand what it is they are really listening to.
 

JUS

Well-known Member
I searched the thread and couldn't find this nugget of information...but I apologise if it's already been covered...

I learned the HDMI standards dictate that the audio bandwidth transmitted over hdmi is limited depending on the video. So transmit a sd video signal over hdmi and you'll get a sd audio signal. You can only get hd audio if you are transmitting 720p or higher.


I lost where I'd seen the information mag, forum or whatever..old age I guess. Took me a few days but I've found it now. It's stated in the Oppo BD83 manual!

I don't have an amp with HDMI to try it (should arrive tomorrow :clap:) so I've not tried it myself but it states if the video output is set to SD then the audio bandwidth is restricted - HDMI spec not the player.

P.S. I'd never believe or even bother talking to anyone from certain av outlets ;) :devil:
 

ares9245

Standard Member
" If you use LPCM, but output via the PS3's digital optical connection, you are limited to 2 and 5.1 channel sound. The multi-A/V-out (either component or composite video) only supports 2 channel audio."

I don't understand this part. What do you mean by "you are limited to 2 and 5.1 channel sound?
PS3 slim is not a problem?

Sorry for my rookie questions. I am just about to buy 50" TV and try to setup a home cinema set. Don't know much about it. I know I'll get a network media center where I can put all my movies on and play it through an amplifier, so I could get HD image and HD surround sound. I understand that I need a optical to connect my media center and amplifier.

I definitely need a blueray player. I am looking at the PS3 slim too. But got confused a bit as said above. So if I connect PS3 slim to amplifier, will it give proper surround sound? Or an outright blueray player is definitely better?

Thanks a lot.
 

dante01

Distinguished Member
" If you use LPCM, but output via the PS3's digital optical connection, you are limited to 2 and 5.1 channel sound. The multi-A/V-out (either component or composite video) only supports 2 channel audio."

I don't understand this part. What do you mean by "you are limited to 2 and 5.1 channel sound?
PS3 slim is not a problem?

Sorry for my rookie questions. I am just about to buy 50" TV and try to setup a home cinema set. Don't know much about it. I know I'll get a network media center where I can put all my movies on and play it through an amplifier, so I could get HD image and HD surround sound. I understand that I need a optical to connect my media center and amplifier.

I definitely need a blueray player. I am looking at the PS3 slim too. But got confused a bit as said above. So if I connect PS3 slim to amplifier, will it give proper surround sound? Or an outright blueray player is definitely better?

Thanks a lot.


The PS3 lacks analogue multichannel outputs. Only HDMI and multichannel outputs can carry HD audio. Only the PS3's HDMI output can carry HD audio. Optical uses the S/PDIF protocol and the S/PDIF protocol cannot handle the bandwidth required for HD audio or the additional channels needed for 7.1.

If you connect he PS3 to an HD capable AV receiver with HDMI audio capabilities via HDMI then you can access the HD audio formats. An optical connection would limit you to SD 5.1 audio formats. The same would be true of any Blu-ray player.

Optical and digital coax audio connections are not suitable for HD audio.
 

MADEINUK

Standard Member
That's the single most concise connection explanation i've read on this forum! More of the same from other members would help cut the confusion related to aspects of this thread.
 

ares9245

Standard Member
The PS3 lacks analogue multichannel outputs. Only HDMI and multichannel outputs can carry HD audio. Only the PS3's HDMI output can carry HD audio. Optical uses the S/PDIF protocol and the S/PDIF protocol cannot handle the bandwidth required for HD audio or the additional channels needed for 7.1.

If you connect he PS3 to an HD capable AV receiver with HDMI audio capabilities via HDMI then you can access the HD audio formats. An optical connection would limit you to SD 5.1 audio formats. The same would be true of any Blu-ray player.

Optical and digital coax audio connections are not suitable for HD audio.
Thanks a lot for your answers. It's getting clearer!

So it doesn't matter if it's PS3 or PS3 slim then.
Why blueray player doesn't support 7.1 format output? HD image quality, but not HD sound quality? Strange!
I guess not many blueray movies have 7.1 audio?
I don't know how many HDMI out put a blueray player has, but it seems it should have at least 2 then.
what are the other analogue multichannel outputs beside HDMI?

Sorry for my rookie questions again.
 

dante01

Distinguished Member
Thanks a lot for your answers. It's getting clearer!

So it doesn't matter if it's PS3 or PS3 slim then.
Why blueray player doesn't support 7.1 format output? HD image quality, but not HD sound quality? Strange!
I guess not many blueray movies have 7.1 audio?
I don't know how many HDMI out put a blueray player has, but it seems it should have at least 2 then.
what are the other analogue multichannel outputs beside HDMI?

Sorry for my rookie questions again.

Both the old PS3 and the new slim need to use HDMI in order to output HD audio.

All blu-ray players support the HD audio formats. All blu-ray players now have HDMI output. HDMI can carry HD audio formats with 8 channels of audio (7.1).

Only HDMI and multichannel audio connections are capable of carrying HD audio. Multichannel outputs are seldom apparent on BD players these days and fewer AV amps now bother with them. HDMI is now regarded as being the standard means by which to stream HD audio and video.

Blu-ray players do support 7.1 output, but only via HDMI (or multichannel outputs (8 RCA outputs for 7.1) if present). BD player and most devices (all BD players) only have one HDMI output.

blurayfeature5.jpg



All this is explained in the first post of this thread.


If you want both HD audio and video then use HDMI.
 
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ares9245

Standard Member
Thanks a lot for your help.
I read your first post twice actually, but still confused.:confused:

"Multichannel outputs are seldom apparent on BD players these days and fewer AV amps now bother with them."
"BD player and most devices (all BD players) only have one HDMI output."

What do you do in this case then? you'll certainlly need that single HDMI for your TV. And multichannel outputs are not so well supported.
 

dante01

Distinguished Member
Thanks a lot for your help.
I read your first post twice actually, but still confused.:confused:

"Multichannel outputs are seldom apparent on BD players these days and fewer AV amps now bother with them."
"BD player and most devices (all BD players) only have one HDMI output."

What do you do in this case then? you'll certainlly need that single HDMI for your TV. And multichannel outputs are not so well supported.



You connect the single HDMI output to an HDMI equiped AV amp that has HDMI audio abilities. The amp deals with the audo and passes the video through to your display via the amp's HDMI output. The TV will also require an HDMI input in order to accept the HDMI signal coming from the amp.

AV amps with HDMI interfaces usually have more than one HDMI input, 3 or 4 is usually the norm, but not all AV amps with HDMI interfaces can handle audio via HDMI. THose that only deal with video switching are referred to as HDMI switchers and those that can deal with both the video and the audio are referred to as repeaters.

You need an AV amp with an HDMI repeater in order to connect an HDMI sources via just HDMI and have it handle the audio coming in via HDMI while passing the video signal through to you display.
 

SyStemDeMoN

Well-known Member
Wonder If anyone can help me.

I recently bought an Onkyo 577, and have been enjoying th e delights of high def audio.

I have the PS3 outputting through HDMI into the amp(LPCM), and have all the audio options on the PS3 ticked (i.e. 192khz 7.1 etc)

So why do I only ever get 48khz output, upto 4.5mb a second ?

Have I not enabled something on the Onkyo ? Or are blu rays with higher bit rates rare ?

I've tried a few now, transformers 2 , spidey 2 + 3 sunshine etc.

The ps3 says its playing DTS HD MA, but I was expecting higher sampling and bit rates.

I am expecting something thats not there ?

And please don't get me wrong, I enjoy the sound I get, but am I getting the fullest ?
 

ares9245

Standard Member
Thanks a lot.
It's clear now!
:thumbsup:

I have been doubting if I should buy a outright blueray player or PS3. Now I see that PS3 could just do the work by using HDMI instead of optical.
Thanks again!
 

dante01

Distinguished Member
Wonder If anyone can help me.

I recently bought an Onkyo 577, and have been enjoying th e delights of high def audio.

I have the PS3 outputting through HDMI into the amp(LPCM), and have all the audio options on the PS3 ticked (i.e. 192khz 7.1 etc)

So why do I only ever get 48khz output, upto 4.5mb a second ?

Have I not enabled something on the Onkyo ? Or are blu rays with higher bit rates rare ?

I've tried a few now, transformers 2 , spidey 2 + 3 sunshine etc.

The ps3 says its playing DTS HD MA, but I was expecting higher sampling and bit rates.

I am expecting something thats not there ?

And please don't get me wrong, I enjoy the sound I get, but am I getting the fullest ?

If there is an option for HDMI audio output on the amp then ensure it is set to AMP and not AMP+TV.
 

SyStemDeMoN

Well-known Member
If there is an option for HDMI audio output on the amp then ensure it is set to AMP and not AMP+TV.

The amp automatically cuts sound from the TV, I have looked in the HDMI options with no joy.

Should I be getter better bitrates then ??
:lease:
 

dante01

Distinguished Member
The amp automatically cuts sound from the TV, I have looked in the HDMI options with no joy.

Should I be getter better bitrates then ??
:lease:

This would be dependant on the source material and the encoded audio. I've no idea what sample rates where used for the films you've been watching, but it isn't a given that all HD encoded audio will actually use the highest rate possible. It is more probable that he rate will be higher than 48kHz in most instances though.
 
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SyStemDeMoN

Well-known Member
This would be dependant on the source material and the encoded audio. I've no idea what sample rates where used for the films you've been watching, but it isn't a given that all HD encoded audio will actually use the highest rate possible. It is more probable that he rate will be higher than 48kHz in most instances though.


Damn.

Could it be the HDMI lead im using ??? About a year old.
Just a cheap o one.
 

SyStemDeMoN

Well-known Member
Well after playing around last nite, I found that one of my HDMI leads was faulty as it no longer works :facepalm:

Going up tesco later to get another one, but I don't think that the cable was limiting the bitrate. They either work or don't right ?

I think I'm going to have to start a new thread about this and request some help.

Will report back when I have tried and tested my new cable.
 

dante01

Distinguished Member
Well after playing around last nite, I found that one of my HDMI leads was faulty as it no longer works :facepalm:

Going up tesco later to get another one, but I don't think that the cable was limiting the bitrate. They either work or don't right ?

I think I'm going to have to start a new thread about this and request some help.

Will report back when I have tried and tested my new cable.

Some cables can limit what you can stream, but you usually end up with no signal in such cases. You should try to get cables that are labelled as category 2. Cat 2 cables are officially tested ans assured to work with 1080p. They also work over a longer distance than category 1 cables.
 

SyStemDeMoN

Well-known Member
ok I got a new cable, HDMI 1.3b and have gotten 7.2mbs from xmen 3 in dts MA.

But I still only get a 48khz sample rate ?
 

dante01

Distinguished Member
ok I got a new cable, HDMI 1.3b and have gotten 7.2mbs from xmen 3 in dts MA.

But I still only get a 48khz sample rate ?

As I've mentioned in this thread and pointed out in another…

http://www.avforums.com/forums/av-a...-str-dh800-owners-thread-62.html#post11084693

… Just because a higher sample rate is possible (up to 192kHz), it doesn't necessarily mean that HD audio will be encoded with a higher sample rate.

You'll find that not all HD audio tracks are encoded with a sample rate higher than 48kHz.

X-Men Origins Wolverine [Blu-ray] Audio:

DTS-HD Master Audio English 3892 kbps 5.1 / 48 kHz / 3892 kbps / 24-bit (DTS Core:
5.1 / 48 kHz / 1509 kbps / 24-bit)
DTS Audio French 768 kbps 5.1 / 48 kHz / 768 kbps / 24-bit
Dolby Digital Audio English 448 kbps 5.1 / 48 kHz / 448 kbps
Dolby Digital Audio Portuguese 448 kbps 5.1 / 48 kHz / 448 kbps
Dolby Digital Audio Spanish 448 kbps 5.1 / 48 kHz / 448 kbps
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps
DTS Express English 96 kbps 1.0 / 48 kHz / 96 kbps / 24-bit
DTS Express English 96 kbps 1.0 / 48 kHz / 96 kbps / 24-bit
DTS Express English 96 kbps 1.0 / 48 kHz / 96 kbps / 24-bit
 
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Bizness

Active Member
If there's a better or more informative poster on these forums than Dante, I've not met them.

Top man D :thumbsup:
 

Shin Akuma

Well-known Member
Quick question about the HDMI cable. I just bought one new cable but when check on the screen sample rate, it is pretty same as with other HDMI cable was. I just wanted to ask does HDMI cable effect the sample rates etc. I checked on Terminator salvation and for me it is mostly 2 to 3 Mbps and 48Khz, and about 20 Mbps on AVC. I will appreciate if some one else can check what sort of reading they are getting.
I bought new cable as last one was bit short. thanks
 

YellowSphere

Well-known Member
BD player and most devices (all BD players) only have one HDMI output.
Sorry to be a pedant, but both the Pioneer BDP-LX91 and Denon DVD-A1UD have dual HDMI outputs (for separate routing of video and audio content to respective devices).

EDIT: Shin; the cable will make no difference. The sample rates/bit rates are inherent properties of the data as stored on the disc, and its transmission between or within devices will not affect this regardless of how it's transmitted. Different cables will impact on the amount of bit errors (data from the original source which doesn't get through for whatever reason) but it's very rare for something to be at a point where there are enough bit errors for you to notice. If the signal gets too corrupted, you'll lose picture entirely.
 
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