Lossless audio over optical?

[natronforever]

Hey everybody,

So last night I watched Mr. and Mrs. Smith on BluRay. Looked great, sounded great. As a point of curiosity, I noticed that the DTS soundtrack was registering as 1.5 Mbps over all 5 channels, which I thought was interesting, especially considering my sound is transmitted from my PS3 via optical to my receiver. Usually my BluRays register around 600-700 Kbps, and I thought 1.5 Mbps required HDMI to transmit, due to bandwidth limitations of the optical connection. Anyway, if anybody could enlighten me on the topic, I'd appreciate it.

[Freewillisdead112]

That sounds quite Interesting!

[Mr Peabody]

I bet Mr & Mrs Smith has a DTS-HD track which can reach 1.5 bps. Dolby Tru-HD is 16 Mbps and DTS-MA is 18.0 Mbps, or I should say they can be.

This article is old but one I found that gives the various formats and their speed.
http://nadelectronics.com/audio-topics/NAD-Technology-Update

[natronforever]

Thanks for the article, Mr. Peabody. So, is 1.5 Mbps considered lossless? At what bit rate is audio considered "lossless?"

[Mr Peabody]

1.5 is better than typical DVD but not Lossless. The DTS is 1.5 Mbps where Dolby Tru HD is 16 Mbps. The DTS-MA (lossless) is 18 Mbps.

[pixelthis]

Thanks for the article, Mr. Peabody. So, is 1.5 Mbps considered lossless? At what bit rate is audio considered "lossless?"

It is the "max out" rate for regular dtsand DD also, btw.
ONE THING about Blu, even the "regular" soundtracks (which you get through the coax
and optical connections) are still the maximum bit rate, which is 1.5 .
You have to run through the 7.1 out (for players that have it) or the HDMI straight
into a receiver with a decoder to get the "lossless", which is why I run mine through the
7.1, which left my SACD player out in the cold, I'm afraid.
But man does it ever sound great.:1:

[canuckle]

You can't transmit anything lossless over optical. DTS has always been 1536kbps... this is nothing new.

[02audionoob]

I run mine through the
7.1, which left my SACD player out in the cold, I'm afraid.
But man does it ever sound great.:1:

Assuming the Sony Blu-ray listed in your signature is a BDP-S300, since a BD-300 doesn't appear to exist, there is no 7.1 output. It's 5.1.

[pixelthis]

Assuming the Sony Blu-ray listed in your signature is a BDP-S300, since a BD-300 doesn't appear to exist, there is no 7.1 output. It's 5.1.

OOPS! You are right, of course, I havent really thought about it, since my system is 5.1.
But 5.1 or 7.1 it really is spectacular.
I have tried 7.1 systems and cant really see the benefit.:1:

[Sir Terrence the Terrible]

It is the "max out" rate for regular dtsand DD also, btw.
ONE THING about Blu, even the "regular" soundtracks (which you get through the coax
and optical connections) are still the maximum bit rate, which is 1.5 .


Wrong again. The maximum bit rate for regular DD is 640kbps, but limitations within the DVD spec limit it to 448kbps. Only Dts utilizes the 1509kbps data rate.

The lossless audio codecs revert to their native bitrates when passed through the optical or coaxial outputs. However uncompressed PCM which is found on early BR releases CAN be passed through both the optical and coaxial outputs. You only get 2.0 sound much like CD, but you get the full uncompressed 16bit audio. Tracks that are encoded at 24bits (and there are some) will have their audio truncated to 16bits, and then outputted to the optical and coaxial outputs. Keep in mind, the both the optical and coaxial were designed to handle 16bit audio which is the redbook standard, not 24bits which would make the audio out of spec through that connection.

[Sir Terrence the Terrible]

Assuming the Sony Blu-ray listed in your signature is a BDP-S300, since a BD-300 doesn't appear to exist, there is no 7.1 output. It's 5.1.

Bingo

[Sir Terrence the Terrible]

OOPS! You are right, of course, I havent really thought about it, since my system is 5.1.
But 5.1 or 7.1 it really is spectacular.
I have tried 7.1 systems and cant really see the benefit.:1:

If you cannot hear the difference between 5.1 and 7.1, you need your ears checked. 7.1 comes in two flavors, and you have to distinguish the difference between. One is a marketing hype, the other true discrete 7.1. The marketing hype is 6.1 with two center rear speakers playing the same thing in mono. The other is true mixed and encoded discrete 7.1.

All one has to do is listen to Surround records 7.1 releases in both 7.1 and 5.1. The 7.1 encoding not only extends the soundfield further back behind the listener, but its mapping of the concert venue is more precise and stable. Soundtracks are re-mixed to 7.1 by either pulling information from the L/R surrounds rearward, or by going back to the original elements and creating a new soundtrack from scratch. Either way you are going to have discrete information mixed and panned directly to the center rear channels in stereo, which will make the rear soundstage more precise, stable, and spacious as well. Take that down to 5.1, and you have lost the precision and stability to a phantom image.

[Mr Peabody]

I don't want to go back and re-read what I've already posted so forgive any repeat.

Blu-ray via optical can sound better than standard DVD because the "core" DD from BR can reach up to 640 kbps where SD maxed at 484 kbps.

Here's a nice page from Dolby with diagrams of many of their multichannel configurations. It also supports and gives a bit more detail on what Sir T was saying regarding 5.1 & 7.1.
http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/DPlus_TrueHD_whitepaper.pdf