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The Media Kit has a number of message formats. The following table lists the messages (by their 'what' constants) and describes their intents. The subsequent sections list the fields that are contained in the messages.
Notification Messages |
Declared in: be/media/MediaDefs.h
Constant Meaning B_MEDIA_WILDCARD Used to match any notification (used only in calls to StartWatching() and StopWatching()). B_MEDIA_NODE_CREATED A new node has been created B_MEDIA_NODE_DELETED Not sent in R4.5. B_MEDIA_CONNECTION_MADE Not sent in R4.5. B_MEDIA_CONNECTION_BROKEN Not sent in R4.5. B_MEDIA_BUFFER_CREATED Not sent in R4.5. B_MEDIA_BUFFER_DELETED Not sent in R4.5. B_MEDIA_TRANSPORT_STATE Not sent in R4.5. B_MEDIA_PARAMETER_CHANGED Indicates that a parameter in a BParameterWeb has changed. B_MEDIA_FORMAT_CHANGED Not sent in R4.5. B_MEDIA_WEB_CHANGED Indicates that a node's BParameterWeb has changed. B_MEDIA_DEFAULT_CHANGED Not sent in R4.5. B_MEDIA_NEW_PARAMTER_VALUE Indicates that a parameter in a BParameterWeb has changed. Unlike the B_MEDIA_PARAMETER_CHANGED notification, this includes the new value. B_MEDIA_NODE_STOPPED Indicates that a node has stopped. B_MEDIA_FLAVORS_CHANGED Indicates that flavors have changed. Messages with these 'what' are sent by the media server to any application that's registered to receive notifications by calling BMediaRoster::StartWatching().
B_MEDIA_NODE_CREATED , B_MEDIA_NODE_DELETED |
Field Type Code Description "be:media_node_id" B_INT32_TYPE The ID of the media_node that was created or deleted.
B_MEDIA_CONNECTION_MADE |
The B_MEDIA_CONNECTION_MADE message has three data fields:
Field Type Code Description "be:output" B_RAW_TYPE A media_output structure describing the connection's output. "be:input" B_RAW_TYPE A media_input structure describing the connection's input. "be:format" B_RAW_TYPE A media_format structure describing the format of the data that flows across the connection.
B_MEDIA_CONNECTION_BROKEN |
Field Type Code Description "destination" B_RAW_TYPE A media_destination structure describing the destination of the connection that's been broken. "source" B_RAW_TYPE A media_source structure describing the source of the connection that's been broken.
B_MEDIA_BUFFER_CREATED |
Field Type Code Description "clone_info" B_RAW_TYPE An area_info structure describing the buffer's location in memory. This is an array, one entry per buffer created.
B_MEDIA_BUFFER_DELETED |
Field Type Code Description "be:media_buffer_id" B_INT32_TYPE The buffer ID number of the buffer being deleted. This is an array, one entry per buffer deleted.
B_MEDIA_FORMAT_CHANGED |
Field Type Code Description "be:source" B_RAW_TYPE A media_source structure describing the source of the connection whose format changed. "be:destination" B_RAW_TYPE A media_source structure describing the source of the connection whose format changed. "be:format" B_RAW_TYPE A media_format structure describing the new format.
B_MEDIA_PARAMETER_CHANGED |
Field Type Code Description "be:node" B_RAW_TYPE A media_node structure indicating which node's parameter web has changed. "be:parameter" B_INT32_TYPE The ID number of the parameter whose value has changed.
B_MEDIA_WEB_CHANGED |
Field Type Code Description "node" B_RAW_TYPE A media_node structure indicating which node's parameter web has changed.
B_MEDIA_NEW_PARAMETER_VALUE |
Field Type Code Description "node" B_RAW_TYPE A media_node structure indicating which node is reporting a changed parameter value. "parameter" B_INT32_TYPE The parameter ID of the changed parameter. "when" B_INT64_TYPE The performance time at which the change took effect. "value" B_RAW_TYPE The parameter's new value.
B_MEDIA_FLAVORS_CHANGED |
Field Type Code Description "be:addon_id" B_INT32_TYPE The add-on ID of the add-on whose flavors have changed "be:new_count" B_INT32_TYPE How many new flavors have been added. "be:gone_count" B_INT32_TYPE How many flavors have been removed.
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