First of all, we have few sound codecs for cinemas. Let us leave about 2 channel stereo sound, the traditional 5.1 channel sound has been so popular.
Dolby’s AC-3 also known as Dolby Digital and its rival from DTS which is DTS 5.1
Dolby’s AC-3 supports bit-rates upto 640kbps, where as DTS gives 1596kpbs.
And then Dolby came up with a compressed loss less audio format Dolby True HD with bit-rates varying from 15 to 18 Mbps where as DTS’s DTA HD MA gives 18 – 24 Mbps. Both supports upto 7.1 channel sound system.
Coming to our original question, now the companies Barco, Dolby and DTS has come up with their own immersive audio codecs and solutions that are Auro 3D, Atmos and X respectively.
Dolby Audio and Auro 3D
It is designed along three layers of sound (surround, height and overhead ceiling), building on the single horizontal layer used in the 5.1 or 7.1 sound format. Auro-3D creates a spatial sound field by adding a height layer around the audience on top of the traditional 2D surround sound system. This additional layer reveals both localized sounds and height reflections complementing the sounds that exist in the lower surround layer. The height information that is captured during recording is mixed into a standard 5.1 surround PCM carrier, and during playback the Auro-3D decoder extracts the originally recorded height channels from this stream.
AuroMax expands on the basic layout used by Auro 11.1 and Auro 13.1 by dividing the side, rear and ceiling channels into “zones”, to allow for placement of sound at discrete points along the theatre wall or ceiling as well as within the theatre itself. The principle employed is similar to other object based formats such as Dolby Atmos or DTS:X.
The Auro-3D technology consists of the Auro-3D Engine and a Creative Tool Suite. The engine comprises the Auro-Codec and the Auro-Matic upmixing algorithm to convert legacy content into the Auro-3D format. The Creative Tool Suite is a set of plugins that can be used to create native immersive 3D audio content. Auro-3D is fully compatible with all existing production processes and theatre systems, and the format also offers a host of compatibility features such as Single Inventory Distribution (multiple formats are combined in one PCM carrier) and full DCI compliancy.
Coming to, Dolby Atmos and DTS:X are object based/oriented. Dolby Atmos contains 7.1 channel bed + virtually unlimited number of audio objects. DTS:X (32 speaker channels supported as of now) which is the most scalable, purely object oriented flexible audio codec recently been addressed by DTS. DTS:X doesn’t require any specifica speaker configuration. It can be accostomed any other immersive formats including Atmos and Auro.
Dolby Atmos Audio
Dolby Atmos is a surround sound technology developed by Dolby Laboratories. It expands on existing surround sound systems by adding height channels, allowing sounds to be interpreted as three-dimensional objects. Following the release of Atmos for the cinema market, a variety of consumer technologies have been released under the Atmos brand, using in-ceiling and up-firing speakers.
DTS: X Audio
DTS:X allows the “location” (direction from the listener) of “objects” (audio tracks) to be specified as polar coordinates. The audio processor is then responsible for dynamically rendering sound output depending on the number and position of speakers available. Dolby Atmos uses a similar technique, although the speaker layout employed by cinema DTS:X is the sum of Dolby Atmos and Auro-3D. The layout showcased at AMC Burbank theatre number 8 has a standard eight channel base layer, a five channel height layer on top of the base layer (on the front and side walls) and three rows of speakers on the ceiling. The surround arrays are bass managed by woofers suspended from the ceiling.
And now comparing IMAX to Dolby audio
IMAX uses their own 6 channel sound solution, unlike Dolby’s AC-3 or DTS’s DTS5.1. IMAX says its sound is about 12000@W RMS power.
IMAX was planning to launch its own immersive audio (3D sound).
DTS:X is drawn from SRS lab’s MDA (multi dimentional audio). MDA facilitates mix once use anywhere feature. Where as Dolby Atmos cinemas mix is different from home or Blu-ray mix. But MDA files can be used in cinemas, satellite broadcaseting, Blu-ray discs and even in DVDs.
To prove the above, now it has been shout out that, IMAX uses MDA for its future movies. IMAX’s immersive sound is not equal to DTS:X but DTS:X and IMAX immersive sound is taken from a common core audio codec file that is MDA.
So far now, we can say Dolby Atmos is better sounding environment when compared to current IMAX’s 6channel sound. But once MDA is adopted to IMAX, it will definitely takes on Dolby Atmos.
Finally I can say, DTS:X will be the winner among the other (Auro3D, Dolby Atmos and IMAX immersive audio taken from MDA).
* Immersive audio consists, ear level and height channels.