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MmChannel_t

Structure that defines an input or output channel

Synopsis:

See below.

Description:

This structure defines an instance of an input or output channel returned from a call to an addon's MediaInput->AcquireInputChannel() or MediaOutput->AcquireOutputChannel() function.

Filters are connected using these channels; an output channel is connected to an input channel. Each channel is stored as a MmChannel_t structure, whose first element is a MmElement_t structure, which provides easy identification.

This structure has at least the following members:

MmElement_t element

The type of media structure this structure represents (in the case of a channel, it's MM_ELEMENT_CHANNEL). The element also contains a unique ID.

int32_t direction

The channel direction. One of MM_CHANNEL_INPUT or MM_CHANNEL_OUTPUT.

MmFormat_t flags

The status of the channel. Can be a combination of:

• MM_CHANNEL_ACQUIRED -- the channel is acquired for exclusive use.
• MM_CHANNEL_INPUTSET -- the input stream for the channel is set.
• MM_CHANNEL_STREAM -- the channel is a streaming (rather than buffered) channel.
• MM_CHANNEL_OUTPUTSET -- the output stream for the channel is set.

MmFormat_t format

The format of the media element, used to negotiate between filters.

MmFilter_t filter

The filter that owns this element.

MmChannel_t lchannel

The channel this element is connected to.

Classification:

Neutrino

See also:

MmAcquireInputChannel(), MmAcquireOutputChannel(), MmAttachChannels(), MmFindChannelsFilter(), MmReleaseChannel(), MediaInput, MediaOutput

The Extending the Multimedia Framework chapter.