Topics covered in this article:
- The Re-render window
- Re-render layouts
- Re-render processing
- Re-render matrix
- Re-render widths and types
- Live vs. offline
- Mapping re-renders to outputs
- Setting the physical outputs available for live re-renders
- Adding and modifying re-render properties
- Exporting re-renders
Introduction
Re-renders generate channel-based outputs from the Renderer’s source selection: either from the real-time input to the Renderer or from an open master file. Re-renders are primarily used to derive stereo deliverables for non-Dolby Atmos distribution. Re-renders are what make the Atmos First strategy work by allowing projects to be mixed in Dolby Atmos without requiring a separate stereo mix. Re-renders can be created from full mixes, beds, objects, or from custom groups defined in the Renderer input configuration. Delivering stereo stems provides maximum flexibility for downstream mastering as needed. Consult the delivery specs for the target service to see what stems, if any, are required.
The Re-render Window
To create, define, and map re-renders, open the Re-render window from the Windows menu, or with Command+R on the Mac or Control+R on Windows.
The Re-render window is a matrix where re-renders are defined by width and inputs, and optionally mapped to physical outputs. Any defined re-renders that are not mapped to physical outputs are available as offline re-renders only. The default configuration of the Re-render window defines 7.1, 5.1, and stereo Full Mix re-renders that are mapped to physical outputs. This can be modified or cleared entirely.
Re-render Layouts
The choices of layout are 2.0, 5.0, 5.1, 5.1.4, 7.0, 7.0.2, 7.1, 7.1.2, 7.1.4, 9.1.6, BIN (Binaural), AmbiX (B-Format), and Loudness.
Re-render methodology:
- The 2.0 through 5.1.4 layouts are rendered using user-adjustable Downmix and Trims settings. These are discussed in the following article.
- 7.1.4 has been added to facilitate adding immersive content to video games for cut-scenes and trailers.
- All re-renders except 9.1.6, BIN, AmbiX are rendered with Spatial Coding applied.
- BIN uses the same Binaural Renderer as binaural headphone monitoring.
- AmbiX re-renders are B-Format four channel (W, Y, Z, X).
- The Loudness export is a 5.1 re-render with soft limiting applied to ensure that loudness analysis made with the Renderer and with third-party tools are compatible. If a non-limited 5.1 deliverable is desired, the standard 5.1 re-render should be used.
Re-Render Processing
For re-renders to be available for real-time output, Re-render processing must first be enabled in the Re-renders tab found in Preferences (Mac) or Settings (Windows).
Depending on the quantity and complexity of re-renders, the CPU load can be adversely affected. The CPU load will be reflected in the CPU Meter in the Renderer Main Window. Best practice is to disable live re-render processing during mastering, or to only have required live re-renders mapped to outputs.
Live vs. Offline
Live re-renders are available when using the Renderer on an external workstation and are used to record channel-based outputs back into the DAW. The word “Live” indicates that the re-renders are assigned to physical outputs and that real-time re-render processing is enabled in Preferences or Settings. If re-render processing is not enabled and the re-renders are assigned to physical outputs, a warning status message appears at the top of the Re-renders window.
When the Renderer source is set to input from the DAW, only live re-renders mapped to outputs are available. When the Renderer source is an open master file, both live and offline re-renders are available. It is possible to have a mix of live and offline re-renders. All live re-renders will also be available for offline export when a master file is open.
Live re-renders can be recorded back into the DAW with the Renderer source in either Input or Master. Note that due to the throughput delay of the Renderer, live re-renders will be subject to delay when recording back into the DAW. Best practice is to include 2-pops when mastering and using live re-renders to help accurately spot live re-renders recording back into the DAW
If recording a 5.1 re-render back into the DAW to use with a third-party loudness measurement plug-in or application, use the dedicated Loudness 5.1 re-render layout which includes the soft clip encoding limiter used in the Renderer and encoding tools. This is needed to ensure that loudness measurement performed with third-party tools from a re-render matches the measurements obtained in the Renderer.
When using the Dolby Audio Bridge, live re-renders are not available as the Dolby Audio Bridge is a one-way audio path. If the Dolby Audio Bridge is set as the audio input device to the Renderer, re-render processing should be disabled. Attempting to output re-renders via the Dolby Audio Bridge while it is set as the Renderer input device will likely result in a feedback loop. It is possible to record live re-renders to the DAW from an open master file if the Dolby Audio Bridge is set as the Renderer audio output device and the input to the DAW.
Offline re-renders are not mapped to physical outputs.
Mapping Re-renders to Outputs
Live re-renders are mapped to outputs in the Map to Live re-render section. To map a re-render:
- Click on any available output to define this as the first (L) channel of the re-render output.
- Once mapped, the outputs will display blue and an arrow will appear to the left to expand the selection to show output channels.
- Re-clicking on a mapped output will cancel it and allow the re-render to be mapped to different outputs.
- If a mapping overlaps with another re-render, a warning appears for confirmation.
- For real-time re-renders, a maximum of 10 re-renders can be created and can be mapped to no more than 64 channels.
Setting the Physical Outputs Available for Live Re-renders
The first available outputs for real-time re-renders are set in the Room Setup window routing tab.
- The routing tab is not visible when using the Send/Return plug-ins as the Renderer audio driver.
- Live re-renders are not applicable when using the Dolby Audio Bridge.
By default, the first output for live re-renders is 23, which is the output following the maximum speaker configuration (22 speakers). If a 7.1.4 speaker configuration is used, the first output that can be assigned for re-renders is output 13. By contrast, if speaker arrays are enabled with a larger speaker configuration (using the Dolby Atmos Mastering Suite), a conflict warning will appear, and the first re-render output will need to be shifted accordingly.
To Add or Modify a Re-render
Choose the Layout of the re-render required; then click Add to create a new re-render. The choices of layout are 2.0, 5.0, 5.1, 5.1.4, 7.0, 7.0.2, 7.1, 7.1.2, 7.1.4, 9.1.6, Bin (Binaural), AmbiX (B-Format), and Loudness. Scroll within the drop-down menu to reveal all the options.
Once added, the re-render will appear with a generic name and will default to be a re-render of the Full Mix.
Click on Properties to:
- Modify the re-render name.
- Change the layout.
- Assign custom group(s) to the re-render.
Properties can be used to modify an existing re-render; however if the re-render is mapped to physical outputs, changes to the layout after creation may create output mapping conflicts.
Selecting Custom allows for the use of the groups defined and assigned in the Input Configuration window. Only inputs assigned to the selected groups will be part of the re-render. This is best practice for creating channel-based stem deliverables. If an ADM BWF .wav or IMF IAB .mxf master file is open, only the groups available when the master file was created will be available. If changes to group membership are needed, convert back to an .atmos package using the Dolby Atmos Conversion Tool and unlock the file for editing in the Renderer.
Once the selection of custom groups has been accepted, they will be displayed in the re-render matrix. 
Exporting Re-renders
All re-renders, whether configured as live or offline, are available for offline export with an open master file as source.
To export re-renders:
- Accept any changes to the Re-render Window.
- Open the Export Re-Renders dialog from File > Export Audio > Re-renders or press Command+E (Mac) or Ctrl+E (Windows).
- Choose the destination Directory for the exported Re-Renders.
- Enter a base name for the re-render filename. This will precede the default or custom re-render names entered in the Re-render window.
- Select the re-renders to be exported. By default, all the re-renders created in the Re-render window will be selected.
- Select if the file export will be an interleaved .wav file or output as multiple mono .wav files.
- The channel order for interleaved Re-render layouts 5.0 and greater is SMPTE channel order, except for 7.0.2 and 7.1.2, which are interleaved for compatibility with Pro Tools.
- All Re-rendered layouts except AmbiX can be output as mono .wav files.
- Multi-mono files will export to a new folder titled as the Re-Render name, whereas interleaved files will export to the top level of the directory specified.
- Channel numbers can optionally be added as a suffix to the individual files (using SMPTE channel ordering). This can be useful when the files will be imported into non-linear editors (NLEs).
- Select if the Entire Master File should be exported. Manually setting In and Out points is useful for removing leaders, 2-pops, and any unnecessary pre-/post-roll to match video file durations.
- The downmix modes used to create 5.1 and 5.1.x as well as Stereo re-renders are displayed in the export window. These are discussed in Appendix E.
Delivering Re-renders
If a delivery specification calls for channel-based deliverables to conform to True Peak limits, dynamics processing will need to be applied to the re-renders in the DAW, either on the recorded live re-renders or imported offline re-renders.