Thread: HD Audio Formats and How to Use Them Explained:

Just to make sure that anyone reading this who is confused about the audio differences I will explain them below.

The current surround formats that are most common today are Dolby Digital 5.1 and DTS 5.1 surround sound. Both formats are compressed audio while DTS uses "less" compression compared to Dolby Digital. Dolby Digital 5.1 is on nearly every current DVD movie and is also used widely on many cable channels both SD and HD channels. Some examples would be SD HBO, ESPN HD, ABC HD etc. DTS 5.1 is only on DVD movies for the mass markets.

The most common way to get both Dolby Digital and DTS 5.1 surround is via either a coax digital audio connection and/or an optical digital audio connection. The player or the receiver "must" be able to decode both Dolby Digital and DTS surround sound respectively. For example most cable boxes "cannot" decode Dolby Digital 5.1 surround sound so your receiver must be able to decode the AC3 (aka Dolby Digital) stream sent from your cable box.

Many DVD players available today can decode both Dolby Digital and DTS 5.1 surround sound and send a PCM signal that your surround receiver can decode.

Dolby Digital and DTS surround sound can also work via 5.1, 6.1 and 7.1 analog audio inputs as well.



Now onto the HD audio stuff. Right now the most common surround format for HD audio that both HD DVD and Blu-Ray HD supports is Dolby TrueHD.

Dolby TrueHD is fully lossless and is bit for bit identical to the original studio master. The problem is that the normal coax and optical audio connections just don't have the bandwidth to pass this full lossless signal.

So as of now the only two ways that are available in mass market products that have the bandwidth to decode Dolby TrueHD are analog audio connections and HDMI. Now nearly all HD movie players can downconvert a Dolby TrueHD signal and send it out either PCM or Bitstream over coax and optical connections but this is again very lossy audio compared to the original TrueHD signal.

Everything above also applies to the DTS HD audio standard as well. Most HD movie players can decode both Dolby and DTS HD audio formats and send them bit for bit over an analog audio connection and/or an HDMI connection.

So simply put to get the full lossless HD audio experience your surround receiver must have either an analog audio input or an HDMI input. Beyond this requirement your HD movie player "must also" have one of these two connections as well.

So say your surround receiver has 7.1 channel analog audio inputs "but" it doesn't have an HDMI input. Well in this case buying a PS3 "WILL NOT" get you this lossless HD audio as the PS3 doesn't have an analog audio output . Because the PS3 only has an HDMI output your surround receiver "must" have an HDMI input to fully support lossless HD audio.

Now again remember that as long as your receiver has a coax and/or optical audio connection nearly all HD movie players will still be able to provide 5.1 surround sound at the least but it again will be lossy and very near DVD type surround sound.

I hope this post can help avoid some of the confusion I believe many readers may have regarding these new audio formats.

Great post! This should help a lot of people!

The DVD standard requires DVD players to handle both PCM audio up to 2 tracks, and DD up to 5.1. DTS is optional as is MPEG-2 audio. Pretty much every DVD has DD on it since PCM takes up way too much room, and DD is the one track they know every player can play.

Excellent post.

So my Onyko receiver that just does HDMI passthrough will not get me 7.1 - and my PS3 connecting to the optical input won't get me 7.1

Nothing will get me 7.1 witout upgrading my receiver, even though it came with the 7 speakers

Oh well, I can't tell the difference anyway, it still sounds damn fine

Great post. That should succinctly answer most questions.

I'm one of those that has a pretty decent A/V receiver, but no HDMI. So I take HDMI from the PS3 to the TV and optical to the receiver. The optical connection from my PS3 obviously only provides lossy sound, but so far BD's seem to have more depth and just overall better sound than DVD's. It may just be me.

Originally Posted by masterdeals

So my Onyko receiver that just does HDMI passthrough will not get me 7.1 - and my PS3 connecting to the optical input won't get me 7.1

What model of Onkyo do you have? Are you sure it won't play the sound from your HDMI input? Of course, I guess you would have noticed the DolbyTRUE-HD and DTS-HD icons on the box and/or receiver.

A piece I found particularly helpful on this subject came from an HD Digest article. To me, I consider this required reading for anyone interested in the topic....


http://www.highdefdigest.com/news/show/1064

Originally Posted by HD MM

A piece I found particularly helpful on this subject came from an HD Digest article. To me, I consider this required reading for anyone interested in the topic....


High-Def FAQ: Blu-ray and HD DVD Audio Explained | High-Def Digest

That is a good article, and it explains the formats in great detail. My only issue with it is that the article is 18 months old and is dated in the area of player support and receiver support.

I expect that this may be the very information that people come here for. Unfortunately, the web sites such as BestBuy.com don't do a very good job. The fact of the matter is that most of the modern players will pass a Dolby TrueHD or DTS-HD bitstream over HDMI-1.3. Many mid-priced players will also support internal decoding to either an uncompressed bitstream or analog outputs as well.

The Amazon site does better at giving this information. Here are a couple of examples:

Sony BDP-S350
Dolby TrueHD decoding built-in Dolby TrueHD /DTS-HD bitstream out over HDMI (V1.3)
(This says that the player will pass both HD formats over HDMI, and will convert Dolby TrueHD to a PCM output as well)

Panasonic BD35/BD55The BD35 and BD55 both feature an HD Audio Decoder (Dolby TrueHD, Dolby Digital Plus and DTS-HD Master Audio Essential), which supports the 7.1-channel surround sound newly adopted in Blu-ray Discs. Users can enjoy 7.1-channel surround even with systems that do not support HD Audio -- as long as the DMP-BD35/55 is connected to a 7.1-channel receiver equipped with an HDMI terminal. The DMP-BD55 can also output analog signals for 7.1-channel sound, so even receivers that are not compatible with HDMI can produce the newest 7.1-channel surround sound by simply connecting to the DMP-BD55.

Sylvania NB500SL9 (but same for Magnavox, Insignia and other Funai sourced players)
HDMI Output and HDMI Cable is included
HDMI or High-Definition Multimedia Interface is an all-digital audio/video interface which can transmit uncompressed streams. HDMI also incorporates Digital Rights Management technology. It is a modern replacement for older analog standards.
(This is very vague, but users have reported that the player will pass DolbyTrueHD and DTS-HD to a receiver that can decode these formats. It will NOT internally decode to a PCM bitstream.)

These models will quickly become obsolete. However, I would expect that future players at a bare minimum will pass the advanced bitstreams over HDMI. For people with older receivers, you will have to still do some research to find the player that will suit your needs.

I was under the impression that the PS3 will not decode the HD Audio. In order to get HD Audio with a PS3 you need to have a receiver that has an HD Audio decoder. Is this true?

Also, I have an Onkyo 606 receiver that is equiped with an HD Audio decoder. If I buy a DVD player that also has this capability then how do the devices determine which one handles the decoding?