Dolby Atmos Basics

Binaural Renderer

All the Bed and Object audio to create an immersive mix over headphones using a head-related transfer function.

Panning sounds between channels that correspond to speaker location.

The number of overhead channels

stereo (2.0) to 7.1.2

multiple beds of differing widths.

SMPTE Channel Ordering for 5.1 to 7.1.2, (L=1, R=2, C=3, LFE=4, Ls=5, Rs=6, Lrs=7, Rrs=8, Ltm=9, Rtm=10)

Objects and Bed channels can be sonically Identical

will be identical to placing the audio in the Left channel bed.

Dolby Atmos

Audio is captured along with associated positional metadata, which include 3D (X,Y,Z) positional coordinates and Object Size, which expands the sound field of an object., Aren’t panned to specific outputs, instead they panned in 3D space.

Object Audio Metadata

Low-Frequency Effects channel

This size and positional information is captured as any changes are made in real time, Upon final content delivery the audio is captured along with the positional metadata for playback on consumer devices.

Cinema

A separate track was required to carry low frequency audio without overloading full range speakers.

It’s Used for Low Frequency Content and is reproduced by a subwoofer.

not the only audio reproduced by the subwoofer.

Bed Audio Only. (Object audio is full range ), It's discarded when dolby Atmos content is played back in stereo or when deriving a stereo re-renderer

Used sparingly and only emphasize very low frequency audio that could cause overloads when combined with other signals.

Main mix. (Do not rely on the LFE to be the “bass channel”)

it’s best to leave the low frequency content in other Bed channels or Objects.

Is used in Dolby Atmos and Applies a crossover frequency that redirects low frequency content from any channel to the subwoofer.

128 tracks of audio

10, Bed audio

118, objects or additional Beds.

That it can be played back on a wide variety of Dolby Atmos enabled devices.

Object Audio Renderer (OAR) and this is referred to as Rendering.

Both Dolby Atmos content creation and consumer playback.

Channel based derivative of the Dolby Atmos master that are generated by the renderer.

Binaural, Stereo, 5.1, all the way up to 9.1.6

Dolby Atmos mixes need more headroom

Dolby codecs that use metadata to ensure proper playback level.

Is not performed on a full Dolby Atmos Mix, but instead on a 5.1 re-render.

First: There isn’t an effective way to measure loudness of an entire Dolby Atmos presentation, Second- This practice ensures loudness continuity between Dolby Atmos content and content is not mixed or presented in Dolby Atmos

Traditional master bus dynamics processing is not available.

Attenuation control with a combination of linked compressor/limiters, groups or Vcas

Dolby Atmos Master File

3, 128

Real-time recording of a dolby Atmos Master File.

Records audios and OAMD directly from the DAW with audio I/O via Dolby Bridge (or Dante or MADI if using an external renderer workstation), Natively Records a Dolby Atmos Master file set (referred to as a DAMF or .atmos fileset)

.atmos, .atmos metadata, .atmos.audio

an XML file containing information about the Dolby Atmos presentation and index information about the other files in the file set.

The number of inputs used as Beds or Objects, spatial coding, downmix, and trim metadata.

An XML file containing dynamic positional and size OAMD for each Object, along with binaural metadata settings.

A core audio Format (CAF) file of up to 128 tracks of interleaved audio

Core Audio Format

ADM BWF

ADM BWF.

Audio Definition Model Broadcast Wav Format

Is an alternative Dolby Atmos master format that is a single file.

All information included in the .atmos.metadata files is included in a data chunk in the header of the .wav file, and audio is up to 128 tracks of interleaved audio

is a single file instead of 3 files in a folder, making it easier to transfer between computers and facilities., The native format of Dolby Atmos enabled DAWs and can be imported into and/or exported from licensed DAWs., Can be encoded Dolby True HD, Dolby Digital Plus JOC, and Dolby AC-4 IMS and is the primary deliverable to mastering engineers, streaming services, and Blu-ray Authoring

Create immersive content with Bed/Object Audio and OAMD from scratch or by modifying imported ADM BWF., Author/Export ADM BWF with Bed/Object audio OAMD as well as Binaural Render Mode, input configuration, group, trim and downmix metadata, Perform Real-time loudness measurements based on 5.1 re-render

-23, -24 or -27LUFS.

-18LUFS

-18LUFS is also used

Suggested target value, not absolute value.

-2dBTP

-1dBTP the limiter that is used in the encoding process will be sufficient to prevent audible clipping.

48khz or 96khz

archival purposes only. At 96khz sample rate

96khz but ADM BWF exports will be sample rate converted to 48khz.

24bit

24fps

1024

2048

Pro Tools needs to have Atmos enabled in the I/O before other atmos functions are available., Is accomplished by enabling Dolby Atmos or inserting Dolby Atmos Renderer plugin on a master track or output

130 outputs and the LTC Generator is usually bussed to output 129 (leaving 128 for bed and object audio)