Components#

An MPEG-H audio scene is made up of Components, Switch Groups and Presets. A Component is made from one or more related sound elements (e.g. the six audio tracks of a 5.1 mix may form one Component.)

Note

The MPEG-H scene can have a maximum of 16 components and 32 audio tracks in total.

Object Components#

An audio object’s position is not determined by the relationship of audio channels fed into a fixed speaker layout, but by position metadata which are transmitted alongside the audio essence, and interpreted by the playback device, optimized for the individual playback situation.

Channel Components#

A Component can be channel-based. These components are typically the representation of a group channel or bus, all automation is already applied before it arrives at the renderer, just like in a legacy channel-based mixdown. This type of Component is often referred to as “Bed”.

Tip

It is considered best practice to place a low pass filter on your LFE signal, before the Authoring stage. The MPEG-H Renderer will not alter the audio on the LFE channel, but it will be low passed on encoding. A low pass filter on the LFE channel at 100Hz will make sure, what you hear during authoring will be equivalent to the signal after encoding.

Creating Components#

New components are created on the source track.

  1. Click on the track’s output and select “MPEG-H Renderer”.

  2. Select “Create new bed” and the bed format to create a new channel component.

  3. Select “assign as object” to create a new (multichannel) object.

  4. The new components will appear in the MPEG-H Renderer.

Note

For every bed component a virtual bed bus is created in the background, so you can route multiple tracks to the same channel component (bed), without having to create Aux Input tracks.

Removing Components#

Components are removed from the scene via the source tracks assignments.

  • To remove an object component, unassign the source track. This can be done by selecting “no output” or another output, making the track inactive or deleting the track from the session.

  • To remove a channel component, the virtual bed bus must be deleted. Select the tracks output and choose “MPEG-H Renderer” > “bed n” > “delete”.

Object Panning#

You can use the “Pro Tools Immersive Panner”” to pan MPEG-H object components. To open the panner, click on the panner icon next to “Object” if a track is assigned as an object.

The panning automation lanes are found under”pan (MPEG-H)”.

Component Properties#

  • Description: Description lets you assign a label to the component, which can be shown to consumers on CE device or player UIs/OSDs. All UTF-8 characters can be used. Label entries are limited to a 20-byte-long expression.

  • Speaker Layout: Layout of a channel component.

  • Headphones Direct: Setting this flag will exclude the Component from binauralization. This option only triggers a behaviour in the binaural renderer. There is no effect if the content is played on speakers or on headphones without binauralization. Select Binaural as the Rendering Layout on the Monitoring tab to preview the effects. Only available for Channel Components in Mono and 2.0 Speaker Layouts.

  • Content Kind: Selection of predefined content kinds. Meta-information for consumer decoders (e.g. decoder switches to audio description if selected).

  • Indicator Color: Color codes the entries in your component list.

  • Switch Group: Select a Switch Group from the drop-down menu to assign the selected component to that Switch Group.

  • Content Language: Definition of language of the audio essence. This information is important for the decoder to activate the right language audio track according to the user’s settings.

Interactivity range settings:

  • Gain min/max: The upper and lower limits of gain [dB] interactivity.

  • Azimuth left/right: “Azimuth“ refers to the interactivity in the horizontal plane.

  • Elevation down/up: “Elevation” refers to the interactivity in the vertical plane.

Tip

With the interactivity range settings, global limits for a component’s interactivity is defined. The activation of interactivy features is done on the Presets tab.

Switch Groups#

Components which are not permitted to be played simultaneously, but should have either/or characteristics, can be placed in a Switch Group. An application for such a Switch Group could be a commentary track in several language versions, which may be selected by the consumer or consumer electronics device during playback.

  • + Switch Group: Adds a new Switch Group.

  • Remove: Removes the selected Switch Group.

Make sure that the relative loudness of all switch group members is approximately the same and within a range of 3 dB LU. This allows seamless switching without loudness level jumps. The integrated loudness of the first Component in the Switch Group will be taken as the reference value for further processing. All other Switch Group members are assumed to have the same loudness value as the first one.

Tip

Regarding the track limits of a MPEG-H master file, only one component of a Switch Group is considered active. An MPEG-H master file can contain up to 32 audio channels, but only 16 active audio tracks are allowed at a time.