Dolby Atmos mixes can be delivered using several different master file formats, each serving as a container for the audio data from beds and objects along with associated metadata such as positional, binaural, and trim/downmix metadata.

The Dolby Atmos Conversion Tool allows conversion to and from Dolby Atmos master file formats.

 

ADM BWF (.wav)

ADM BWF has been developed as an open standard for the storage of object-based audio and metadata, as an extension of the BWAV (Broadcast Wave) format. An ADM BWF master file carries all bed and object audio as PCM audio alongside a metadata chunk that includes all metadata.

 

This format is widely accepted by streaming service providers and music labels for delivering Dolby Atmos mixes. ADM BWF files can be exported and imported directly in many Dolby Atmos-enabled DAWs, including Avid Pro Tools, Apple Logic Pro, Steinberg Nuendo and Cubase (Cubase only supports export), Fender Studio Pro, DaVinci Resolve, Merging Pyramix and Magix Sequoia.

 

DAMF (Dolby Atmos Master Fileset) (.atmos)

Prior to the standardization of ADM BWF there was no suitable container format for object-based audio, leading to the creation of the Dolby Atmos Master Fileset (DAMF). A DAMF consists of three files (.atmos, .audio, and .metadata), all of which must be in the same folder. The .audio file contains the PCM audio, the .metadata file includes positional metadata, and the .atmos file contains trim/downmix and binaural metadata, general information about the master, and references to the .audio and .metadata files. Please note that renaming the .audio or .metadata files will break these references, rendering the file unreadable.

DAMF is the native file format generated when recording a Dolby Atmos master in Dolby Atmos Renderer application. DAMF is the only master file format that can be used by Dolby Atmos Renderer application for punch-ins, recording mix updates, and editing metadata.

 

IMF IAB (.mxf)

IMF IAB is an MXF file that carries audio and metadata in an Immersive Audio Bitstream (IAB), which has been standardized by SMPTE. The advantage of IMF IAB files is that they fit into IMF file containers, enabling the packaging of picture, subtitles, channel-based audio, and Dolby Atmos audio in a single IMF. This can be very useful for delivery, quality control, and archiving for large OTT streaming services.