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Exposing Capture and Compression Formats

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[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

This article describes how to return capture and compression formats by using the IAMStreamConfig::GetStreamCaps method. This method can get more information about accepted media types than the traditional way of enumerating a pin's media types, so it should typically be used instead. GetStreamCaps can return information about the kinds of formats allowed for audio or video. Additionally, this article provides some sample code that demonstrates how to reconnect the input pin of a transform filter to ensure your filter can produce a particular output.

The GetStreamCaps method returns an array of pairs of media type and capabilities structures. The media type is an AM_MEDIA_TYPE structure and the capabilities are represented either by an AUDIO_STREAM_CONFIG_CAPS structure or a VIDEO_STREAM_CONFIG_CAPS structure. The first section in this article presents a video example and the second presents an audio example.

This article contains the following topics:

Writing DirectShow Filters