Threads and Critical Sections

This article describes threading in DirectShow filters, and the steps you should take to avoid crashes or deadlocks in a custom filter.

This article contains the following topics.

• The Streaming and Application Threads
• Pausing
• Receiving and Delivering Samples
• Delivering the End of Stream
• Flushing Data
• Stopping
• Getting Buffers
• Streaming Threads and the Filter Graph Manager
• Summary of Filter Threading

See Also

• Data Flow for Filter Developers

The examples in this article use pseudocode to illustrate the code you will need to write. They assume that a custom filter is using classes derived from the DirectShow base classes, as follows:

• CMyInputPin: Derived from CBaseInputPin.
• CMyOutputPin: Derived from CBaseOutputPin.
• CMyFilter: Derived from CBaseFilter.
• CMyInputAllocator: The input pin's allocator, derived from CMemAllocator. Not every filter needs a custom allocator. For many filters, the CMemAllocator class is sufficient.