Version 2025.04

1.  Mix and approval environment

1.1    All deliverables SHOULD be mixed, approved for home listening, and monitored in a room with at least a 5.1.4-ch speaker layout, however 7.1.4 is highly recommended.

1.2    All deliverables SHOULD be monitored over headphones, with the Dolby Atmos Renderer’s headphone render mode set to “Binaural”, ensuring the presence of Binaural Headphone Metadata.

1.3    Additionally, all deliverables SHOULD also be monitored through a 5.1.x speaker configuration for confidence checking of Trim & Downmix metadata.

1.4    The mixing and approval environment SHOULD conform to the Dolby Atmos Home Entertainment Studio Technical Guidelines

 

2.  Synchronization and alignment

2.1    All deliverables MUST be created with a timecode frame rate of 24 fps.

2.2    If using the Dolby Atmos Renderer, or a DAW with an integrated Dolby Atmos Renderer that supports FFOA (first frame of action), the FFOA field MUST be left unassigned.

2.3    All stereo re-render deliverables MUST be conformed and synced to the main Dolby Atmos deliverable.

2.4    There MUST be no additional silence at the start of the Dolby Atmos deliverable when compared to the corresponding stereo deliverable.

 

3.  Loudness

3.1    Loudness SHOULD be measured using the Dolby Atmos Renderer.

• • Note that loudness may also be measured using a DAW with an integrated Dolby Atmos renderer, or a 3rd party loudness measurement plug-in or application. For Dolby Atmos loudness measurement a 5.1-ch re-render is used. A loudness-specific 5.1-ch re-render is available for export from the Dolby Atmos Renderer for use with 3rd party plug-ins and applications

3.2    The target Dolby Atmos integrated loudness SHOULD be -20 LKFS +/- 2 LKFS, when measured according to ITU Recommendation BS. 1770-4.

3.3    If the percentage of speech measured in the deliverable is 15% or higher, the Dolby Atmos speech-gated integrated loudness SHOULD be used.

3.4    If the percentage of speech measured in the deliverable is less than 15%, the Dolby Atmos level-gated integrated loudness SHOULD be used.

3.5    Peak levels SHOULD not exceed -0.1 dBTP for the Dolby Atmos loudness measurement.

3.6    All deliverables MUST use the same 5.1 and 5.1.x downmix setting and 5.1 trim control values for the Dolby Atmos loudness measurement that are used in the final delivery.

 

4.  Dolby Atmos master deliverables

General

4.1    All master deliverables MUST be provided as an ADM BWF (.wav) file or an IMF IAB (.mxf) file.

• • IMF IAB is a mezzanine format that uses lossless compression to substantially reduce file size compared to an ADM BWF file. IMF IAB (.mxf) files can be exported from the Dolby Atmos Renderer or Dolby Atmos Conversion Tool.

4.2    The number of PCM channels in the master deliverable MUST NOT exceed 128.

4.3    The number of objects in the master deliverable MUST NOT exceed 118.

4.4    All master deliverables MUST use 24-bit, 48 kHz PCM.

4.5    If present, audio in the LFE channel of the master deliverable SHOULD be band limited using a low pass filter with a cut off frequency of between 100 and 150 Hz.

4.6    All master deliverables SHOULD have the Binaural Render Mode setting (Off, Near, Mid, Far) specified for each Bed Channel and Object.

4.7    All Chapters SHOULD make use of the same Binaural Render Mode setting (Off, Near, Mid, Far) for each Bed Channel and Object, ensuring consistency across the whole production.

4.8    All deliverables SHOULD use a 5.1 and 5.1.x downmix setting of “Lo/Ro”.

4.9    All deliverables SHOULD use a 5.1 to 2.0 downmix setting of “Lo/Ro”.

4.10   All deliverables SHOULD have Trim & Downmix metadata set appropriately for the content and be checked on various monitoring configurations.

Bed and object layout

4.11   A single composite bed, or multiple stem beds with channel configurations from LCR to 7.1.2 may be present.

4.12   Tracks 1 to 10 MUST be reserved for bed channel audio even if this is not used in the mix.

4.13   The remaining tracks may be assigned to additional beds or objects as required.

 

5.  Channel-based deliverables (if required)

5.1    Stereo mix deliverables SHOULD be derived from the Dolby Atmos mix and exported as a stereo re-render from the Dolby Atmos Renderer or DAW.

5.2    Stereo deliverables SHOULD be 24-bit, 48 kHz stereo interleaved .wav files.

5.3    Loudness and true peak specifications for stereo deliverables SHOULD meet the requirements from the target distribution platform.

• • Note that this may require additional level adjustment and/or limiting of the 2.0 re-render within your DAW prior to delivery.

5.4    Loudness for the stereo deliverables SHOULD be measured using the Dolby Atmos Renderer or in a DAW with an integrated Dolby Atmos Renderer. 

• • Note that loudness may also be measured by exporting a stereo re-render for use with 3^rd party plug-ins and applications.

 

6.  Dolby Atmos encoded deliverables

6.1    If required, encoded deliverables SHOULD be provided in Dolby AC-4 with Dolby Atmos (AC-4 L4), Dolby Digital Plus with Dolby Atmos (DD+JOC) and Dolby AC-4 immersive stereo (AC-4 IMS) formats

6.2    AC-4 L4, DD+JOC and AC-4 IMS SHOULD be encoded using the Dolby Media Encoder or Dolby Encoding Engine applications.

• • AC-4 L4, DD+JOC and AC-4 IMS can be output as bitstream files or muxed into an MP4 file container directly from Dolby Media Encoder and Dolby Encoding Engine.

6.3    For advice on common encoding settings, please refer to online support documentation at professionalsupport.dolby.com, or contact your local Dolby representative.