Audio Authoring for Dolby Atmos®
Nuendo is the premier DAW available today that enables you to mix a movie or television series for Dolby Atmos® completely “in the box”. The workflow is the same as any traditional post-production project, but you now have the tools to assign beds and objects from tracks in an existing Nuendo project. You can also create an entirely new Dolby Atmos project from scratch. With the integrated Renderer for Dolby Atmos, you can author, mix and deliver Dolby Atmos-compliant ADM Broadcast Wave files and, at the same time, the final stems in different surround configurations.
A post-production project usually consists of many mono audio tracks — containing the dialog and sound effects clips — and group channels that organize the sounds in submixes or stems. For an object-based mix this basic structure can be preserved, as it already offers many advantages. Depending on the delivery requirements, the ADM project will comprise one or multiple beds — for example, background sound and music — and a number of objects, including the dialog, Foley and other sound effects.
Setting up the Renderer
When monitoring an object-based project, all the audio will be routed through the Renderer for Dolby Atmos, therefore it will have to be inserted into the project’s main output bus. The Renderer supports 2.0, 5.1, 7.1, 5.1.4 and 7.1.4 configurations. The configuration of the output bus will determine the maximum channel width of the rendering output and should match the speaker configuration of the room.
The Renderer can only be used with a project sample rate of 48 kHz and an ASIO buffer size of 512 samples.
Beds are channel-based submixes, very much like the stems in an existing Nuendo project. Start by creating a group channel for each bed (if it does not yet exist) — for example, two 7.1 groups for the background sound and the music. All tracks routed to these groups will be part of the bed mixes.
In the ADM Authoring window, create as many beds as necessary — following the previous example, two beds in a 7.1 configuration — and use the previously created group channels as sources. The beds are now ready, with their audio routed through the Renderer.
Any audio track in a project can become an ADM object. You can create objects in the Authoring window and then assign any of the audio tracks from the project as the source. To convert an existing Nuendo project with a large amount of audio tracks into an object-based project, you can just select the tracks in the project window, go to the Authoring window and use the Create Objects from Selected Tracks function. The new objects will automatically be created with their audio routed through the Renderer.
Objects and beds are monitored through the Renderer, which means their audio is not summed in the MixConsole. During the mixing process, you will only listen to the Renderer's output.
Otherwise the usual channel-mixing techniques can be used, but with new and creative possibilities for immersive panning. Writing automation in the VST MultiPanner will transmit panning information as metadata to the Renderer, which will then pan the signal accordingly, in real time.
When exporting an object-based project, the master file must keep all objects separated. Beds and objects in the Authoring window can be exported as an ADM Broadcast Wave file. The file will contain all audio objects and beds, as well as all dynamic panning metadata and static metadata. It will also include rendering instructions for the playback device. When loaded into a playback system, an ADM mastering application, another DAW that supports Dolby Atmos or other Dolby encoders, the metadata will be applied.
Creating a channel-based downmix
The Renderer can also create a channel-based, downmix version of the object-based mix. In the Renderer panel, choose the surround (or stereo) format to which you want to downmix your project. In the Export Audio Mixdown window, select the channel containing the Renderer plug-in and use the Split Channels option. This will produce the correct number of audio files for your downmix, plus a number of files with no audio you can ignore.
Importing ADM files
If your project starts with an ADM file — e.g. from the Dolby Atmos Production Suite — you can easily import it into a Nuendo project for further mixing or editing with the object automation intact. Bed and object audio channels, pan automation, program-level metadata and Group structure are all supported, with audio from ADM extracted to tracks in the Nuendo project. Folder tracks are created to represent the ADM Program/Group structure, while object tracks are assigned to the VST MultiPanner, with existing pan automation.