Introduction

To use ADTF in a common generic way we are providing tools and utilities for convenience access and generation to handle the Data Definiton Language (DDL).
With this language you are able to describe the stuctured content of the data sent via by Sample Streams from one Filter to another (as well as using Streaming Services).

The package will provide a default ADTF Stream Meta Type and many functionality around that support utilities writing, reading and describing memory content (sample content) with the help of the DDL. Currently ADTF comes with 2 DDL Packages:

The open source DDL Library which is delivered with this SDK ($(ADTF_DIR)/pkg/ddl).
For legacy reason, there is the old one ddl library variant under ADTF DDL SDK (Legacy Package) which is delivered with this SDK ($(ADTF_DIR)/pkg/adtfddl)

Dependency

The ADTF Media Description SDK depends on the ADTF Streaming SDK and the Open Source DDL Library and the ADTF DDL SDK (Legacy Package).

C++ Classes

Namespaces

adtf

Namespace for entire ADTF SDK.

mediadescription

Namespace for the ADTF Media Description SDK.

Namespaces for the open source DDL Library

ddl

definition of the ddl namespace

dd

definition of the dd namespace

codec

Namespace for the new faster CodecFactory/Decoder/Codec implementation.

access_element from dev_essential

definition of the access_element namespace (codecs)

Main Classes and interfaces

stream_meta_type_default

stream_type_default

Generator template to create an instance of the stream_meta_type_default.

stream_type_default_array

Generator template to create an instance of the stream_meta_type_default.

md_sample_data

Template to provide media description based access to Sample data.

decoding_sample_reader

This reader uses the media description to decode sample data.

encoding_sample_writer

Sample Writer that provides samples that can be updated via a Codec.

cSampleCodecFactory

Factory class for ddl codecs for samples.

cStaticSampleDecoder

Decoder for samples with static data content.

cSampleDecoder

Decoder for samples with static and/or dynamic data.

cStaticSampleCodec

Codec for samples with static data content.

cSampleCodec

Codec for samples with static and/or dynamic data.

structure<T>

This is used to create a structure type from an existing c++ struct definition.

see Use structure class or section_ddl_file_structuregenerator_defining how to use it

enumeration<T>

This is used to create an enumeration ytpe from an existing c++ enum.

see Use structure class or section_ddl_file_structuregenerator_defining how to use it

Important Class out of the Open Source DDL Library

ddl::DDStructure

Utility class for a complete valid data definition of one StructType and its dependencies.

see Use structure class how to use it

ddl::DDStructureGenerator

Creating a valid Structure Data Definition by a existing type and its member types.

see Use structure<> template how to use it

ddl::DDString

Convenience class to load and validate a Data Definition xml string.

see Define a huge string for DDL Description how to use it

ddl::DDFile

Convenience class to load and validate a Data Definition form a xml file string.

see Read the DDL file and setup Stream Type how to use it

ddl::CodecFactory - old codec API of dev_essential

Factory class for ddl codecs.

ddl::codec::CodecFactory - new codec API of dev_essential

Factory class for ddl codecs.

ADTF standard stream types

Within ADTF data are described via stream types as instance of stream meta types: ADTF standard stream types can be handled in a common way for visualizations and transformations in a generic ways.

Using DDL within ADTF 3

For information on how to generate and use such DDL descriptions have a look at:

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