Media integration

This article talks about the requirements regarding the media integration for a product that includes a Dolby Car Experience Implementation.

Signaling capabilities of the media stack

The media stack signals the capabilities of the Implementation to the application layer and routes matching content to the Dolby Car Experience Implementation, so that player applications can operate correctly. Your applications offer Dolby Atmos content only after querying the capabilities of the product.

Products that integrate a Dolby Car Experience Implementation support decoding and rendering of Dolby Digital Plus bitstreams with Dolby Atmos content, as well as 5.1-, 7.1-, and 2.0-channel-based content. Only such content must be routed to the Dolby Car Experience Implementation. Refer to the "Using EC3SpecificBox information" section below for more information on extracting these attributes out of the incoming bitstream.

Products that include other Dolby Digital Plus decoder Implementations in addition to the Dolby Car Experience Implementation, implement the logic in the media stack to route the content to the right Implementation for each use case. Content for Dolby Car Experience use cases is routed exclusively to the Dolby Car Experience Implementation. The behavior for other use cases is specified by the corresponding Dolby product.

Using EC3SpecificBox information

Common information specific to Dolby Digital Plus is carried in these locations:

• EC3SpecificBox in the stsd atom
• BSI in the Dolby Digital Plus stream

The EC3SpecificBox is intended to be used by the system for information only. For example, the system might use the EC3SpecificBox for any of these scenarios:

• When informing the onscreen display of the channel configuration of the audio stream
• When offering the user the ability to select between the different audio services that are being carried (for example, in the case where multiple independent substreams are present)
• During recovery from errors (for example, if there is an interruption in audio data delivery and the system cannot ascertain the configuration of the complete Dolby Digital Plus bitstream from the substream structure in the MPEG-DASH sample due to CRC errors)

Because it is possible that differences may occur between the EC3SpecificBox and the parameters of the Dolby Digital Plus bitstream, this information must not be used to configure the audio decoder or the audio subsystem of the product. If the product encounters a conflict between the Dolby Digital Plus BSI values and the corresponding parameters in the EC3SpecificBox, the product must always use the values in the bitstream, because the BSI is more accurate.

Dolby Implementations used in parallel

Dolby audio decoder Implementations can be used in parallel with your Implementation of the Dolby Car Experience System Development Kit. This is the case if your Dolby Car Experience Implementation uses, for example, multiple instances of the Dolby Digital Plus decoder, or supports broadcast or Blu-ray use cases. Each instance of a Dolby Car Experience Implementation can process one bitstream at a time. To process multiple bitstreams, you can create multiple Dolby Car Experience instances and run them in parallel within the same process.

Note: In the context of adaptive streaming and transitioning across different representations of Dolby Atmos content, multiple instances of Dolby Car Experience can be used temporarily.

If your Implementation uses parallel Dolby Implementations, contact Dolby at systemsupport@dolby.com.

Multiple instances of Dolby Car Experience

There are products that include multiple signal paths for media playback to support different applications and services. Each signal path that supports playback of Dolby Audio or Dolby Atmos must conform to the Dolby Car Experience product requirements and will be evaluated accordingly. If different Implementations of Dolby Car Experience are used for those alternative signal paths, each of them must be an approved Implementation by Dolby.

Streaming

This version of the Dolby Car Experience System Development Kit supports only MPEG‑DASH. Smooth Streaming and HLS are not supported. The only sample rate that is supported for Dolby Digital Plus in streaming services is 48 kHz.

Integration of streaming services

Streaming services can be integrated into the IVI system by means of an application provided by the streaming service provider or through the native integration of that service into the media stack.
For native streaming services, we suggest partners follow our Music Service Brand Guidelines, which shows where and how to indicate Dolby Atmos within general service user interface (UI)/user experience flows.

Streaming applications

Streaming services and streaming applications can control whether content is streamed in Dolby Atmos or other formats depending on catalogue availability or user preference settings.

IVI systems may have different audio profiles and settings that are optimized for a specific format or use case. Some of these settings may set the product into an operation mode that does not support Dolby Atmos. Two different strategies can be used to deal with operation modes that do not support Dolby Atmos:

1. Allow user override if the user selects content in Dolby Atmos from the streaming service. The IVI system automatically switches to a different operation mode during playback of Dolby Atmos content.
2. Reconfigure user preference settings for streaming services not to stream Dolby Atmos content. This option is not preferred.