What is Dolby Digital Plus, and how does it relate to me getting 5.1 from my Chromecast

Craig King

Well-known member
Nov 17, 2012
253
0
0
Visit site
I have seen a few threads and wanted to write something up that would hopefully help clear up some issues with expectations/confusion with audio from the Chromecast

As of right now Netflix and many other streaming services use Dolby Digital Plus to provide multichannel audio for video content. We would all hope that this multichannel audio would be easily accessible, and for the most part it is. There are a few gotcha's though.
  1. Dolby Digital Plus isn't backwards compatiable with Dolby Digital. I have seen people say it is and that simply isn't true
    Dolby Digital isn't really backwards compatiable with Dolby Digital 5.1, but all de-coders are required to be able to output the older version. This provides some level of support as long as it has a valid decoder. This would allow lets say a Xbox with software decoding to stream dolby digital 5.1 to a older AVR.​
  2. Dolby Digital Plus requires HDMI 1.3 to be output.
    This is simply a requirement of the huge change in bitrate and functionality Dolby Digital Plus provides. The downside to that is that SP-DIF connections can not support it. If you must use SP-DIF output then the device between the Chromecast and the SP-DIF port has to be to decode the Dolby Digital Plus bit-stream and then down convert to the older Dolby Digital 5.1.​
  3. Dolby Digital Plus was designed as a lossy multichannel option with a wide range of abilities to support streaming and portable devices.
    It really is a great improvement over the older Dolby Digital 5.1 standard, but the fact it is new and designed for streaming devices means that allot of equipment may not have it if they don't fall into that category. Think of it like this. If a AVR was made with the expectation that Dolby True HD was going to be the standard and never had the expectation to have streaming to it, then they probably would never of included that standard. To that same extent a TV with built in Netflix can probably decode it fine and even down convert to Dolby Digital 5.1 for a older AVR​

If you can't get Dolby Digital Plus working here are a few things you should check.

Make sure the content has 5.1 to provide to the AVR. The best option I can give you right now is to try to stream "The Hunger Games" from Netflix.

First what is the Chromecast connected to?
If it is a AVR look through the manual and make sure it can decode Dolby Digital Plus in Hardware. If the AVR can decode DD+ then make sure you have it set correctly to auto detect the stream. If the AVR doesn't have the ability to decode DD+ you are pretty much stuck since there is nothing else in between the AVR and the Chromecast to decode and down convert. You may want to take a closer look at your TV and what functionality it has.​
If it is a TV, is this a smart TV, and how is the audio being passed to the receiver? You have to use HDMI and it has to be v1.3 of that port. SPDIF wont' support DD+ but should do the older Dolby Digital if the TV can decode the DD+.​


See the real catch here is you have to have something to decode the bit stream for DD+. From what I am seeing it appears that allot of people are thinking it is working on other devices when in reality they are using something other then their TV or AVR to do the decoding. All of the video game consoles are a great example. They actually have software audio decoders built into them, and are likely doing the conversion before the stream even gets to the AVR.
 
Last edited:

John Smith121

New member
Dec 25, 2013
2
0
0
Visit site
If it is a AVR look through the manual and make sure it can decode Dolby Digital Plus in Hardware. If the AVR can decode DD+ then make sure you have it set correctly to auto detect the stream. If the AVR doesn't have the ability to decode DD+ you are pretty much stuck since there is nothing else in between the AVR and the Chromecast to decode and down convert. .

That is nonsense. This is why people need to be mindful of all the misinformation out floating on the web.

Per Dolby's website ( Dolby Digital Plus Surround Sound for Digital Entertainment ) under tab "how it works"
Compatibility with Current Equipment

Because Dolby Digital Plus content is easily converted to a traditional Dolby Digital signal, you are assured of the best performance your equipment is capable of, regardless of when you purchased it. If your system includes a Dolby Digital decoder, you'll still get 5.1-channel surround sound, with the highest quality Dolby Digital signal possible.

Equipment with Dolby Digital Plus will unlock its full feature set, including 5.1- and 7.1-channel capability (depending on the program).

In other words, you will still be able to get 5.1 audio with the old Dolby Digital decoder and a Dolby Digital Plus signal. However Dolby Digital Plus mandates the use of HDMI 1.3 interface for transport. So if you plug the Chromecast to a receiver that only supports HDMI 1.2 or below, Chromecast will only be able to send 2-channel stereo.
 
Last edited:

Trending Posts

Forum statistics

Threads
943,074
Messages
6,917,165
Members
3,158,809
Latest member
JaydenWhitfield