Broadcast-driven system (TTS) series of lectures: 4

Function topology ):

The goal of bad is that the overall architecture of bad can not be changed much regardless of the hardware or reception signal. Therefore, the concept of functional topology is introduced by the worker, it uses a structure similar to DirectShow filter as a node and includes it in a worker er.
Filter, so a filter can do a lot of work, depending on which node the filter contains and what functions these nodes have. Functional topology only describes a structure, and the specific work is distributed to each node in the topology. In our program, an externally visible filter: Tunner
Filter, actually contains two nodes, tuner
And demodulator. The node in the topology graph is not applicable to any type. Categornode category guidsNode types listed in the List can be added to the graph. node functions are also completed by registering the distribution routine.

Worker node category guids:

Ksnode_bda_rf_tuner

Ksnode_bda_qam_demodulator

Ksnode_bda_qpsk_demodulator

Ksnode_bda_8vsb_demodulator

Ksnode_bda_opencable_pod

Ksnode_bda_pid_filter

Ksnode_bda_ip_sink

Each node has a specific guid. When the network provider filter is connected to the Tunner filter, it searches for the corresponding node based on the guid and generates an instance. Tunner
The filter also uses template topology to describe the types and Connection Methods of each pin and node.

As shown in, the entire figure is a functional topology. Tunner node and demodualator node are two nodes with specific guids.
The Tunner filter is dynamically generated when the provider filter is connected to the Tunner filter. Pin1 is connected to the Tunner node instead of the demodulator. The Tunner node is prior to the demodulator node, and the subsequent information is template.
Topology decides, and the entire graph connection is also completed dynamically based on the template Topology when the network provider filter is connected to the Tunner filter.

However, it is not hard to specify several nodes in a filter. For example, in the figure above, a filter can contain two nodes or be split into two filters. Each filter contains one node, see what you like.

Common nodes include network provider, tuner, demodulator, capture, and network.
The provider currently has many ready-made filters available, which may need to be modified when DMB is used. Most of the time they can be used directly. Tunner and demodulator are now placed in the same filter, called Tunner.
Filter; capture filter is the core part. It reads data from hardware and transmits data back. Generally, it is made into a separate filter. Worker also provides many other nodes to help us do a lot of work. For example, PID filter Node
In fact, demultiplexer filter is used, but so far I have not used PID filter node, but demultiplexer filter in DirectShow.