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    Dolby Atmos Audio

    This topic explains how you can retain Dolby Atmos audio in your video renditions in Video Cloud.

    Introduction

    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.

    Prerequisites

    The following are required to retain Dolby Atmos in (some) renditions:

    • The account must be enabled for multiple audio tracks by Brightcove Support.
    • You must also request that the Dolby Atmos audio rendition be enabled for your account.
    • Dolby Atmos pass-through works only when the source contains a Dolby Atmos rendition.
    • Note that Complexity index must be present in the metadata (the value does not matter).

    To know if a video has Dolby Atmos audio, you can use a an app such as MediaInfo. The output should look something like this:

    Audio
    Format                                   : E-AC-3 JOC
    Format/Info                              : Enhanced AC-3 with Joint Object Coding
    Commercial name                          : Dolby Digital Plus with Dolby Atmos
    Codec ID                                 : A_EAC3
    Bit rate mode                            : Constant
    Channel(s)                               : 6 channels
    Complexity index                         : 16
    ...

    Implementing Dolby Atmos passthrough

    Before starting, note that Video Cloud will copy the Dolby Atmos rendition without any modifications or encoding.

    To implement Dolby Atmos passthrough, you must add the new rendition to an Ingestion Profile.

    Steps

    1. Login to Studio and click the Admin icon in the lower left corner:
      Admin Icon
      Admin Icon
    2. Select Ingest Profiles from the Admin pages menu:
      Admin Pages Menu
      Admin Pages Menu
    3. In the ingest profiles list, click the name of the one that generally best fits your need to open it:
      Ingest Profiles List
      Ingest Profiles List
    4. Click Duplicate.
    5. A copy of the ingest profile opens up. Edit the name if you want to, and then click Advanced Editor:
      Click Advanced Editor
      Click Advanced Editor
    6. In the renditions array, add "default/dolby_atmos" as shown below:
      {
        "dynamic_origin": {
          "renditions": [
            "default/dolby_atmos",
            "default/video450",
            "default/video1200",
            "default/audio128",
            "default/progressive2000",
            "default/video700",
            "default/video2000",
            "default/video1700",
            "default/audio64",
            "default/audio96",
            "default/audio192",
            "default/video900",
            "default/video3500"
          ],
          "images": [ ...
    7. Click Save

    See Creating Ingest Profiles for Dynamic Delivery for the full details of how to create custom ingest profiles.

    Best practices

    If you using Dolby Atmos passthrough renditions, we recommend the following:

    • Be sure you archive the master in case you want to retranscode the video later.
    • To have audio playback on devices that do not support Dolby Atmos, add a regular audio rendition to the Ingestion Profile.

    Limitations

    • Clipping - Atmos is not supported at the moment.
    • EAC3 is the only valid codec supported with Atmos as pass-through.
    • True-HD with Atmos cannot be converted to EAC3 at the moment.
    • True-HD codec is not a supported codec for MP4 formats.

    Page last updated on 07 Sep 2022