CBaseOutputPin class

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The CBaseOutputPin class is an abstract base class that implements an output pin.

This class derives from CBasePin. It differs from CBasePin in the following respects:

• It connects only to input pins that support the IMemInputPin interface.
• It supports local memory transport through the IMemAllocator interface.
• It rejects end-of-stream, flush, and new-segment notifications. (These should not be sent to an output pin.)
• It provides methods for delivering samples downstream.

When the pin connects, it requests a memory allocator from the input pin. Failing that, it creates a new allocator object. The output pin is responsible for setting the allocator properties. It does this through the pure virtual method CBaseOutputPin::DecideBufferSize. Override this method in your derived class. If the input pin has any buffer requirements, they are passed to the DecideBufferSize method.

Call the CBaseOutputPin::GetDeliveryBuffer method to obtain an empty media sample. Call the CBaseOutputPin::Deliver method to deliver samples downstream.

Your derived class must override the pure virtual CBasePin::CheckMediaType method to validate the media type during pin connections.

Requirements