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MmStart()

Start a multimedia graph

Synopsis:

int32_t MmStart(void *element,
                MmTime_t mt);

Arguments:

element

A pointer to a graph or filter.

mt

The current media time, in milliseconds. See below.

Library:

mmedia

Description:

This function starts a graph's filters, or an individual filter if element is a filter, starting at the time mt (in microseconds). The element argument is type void * to prevent compiler errors when you pass different structures as this parameter.

If element is a graph, the function calls all the graph's filters' MediaControl->Start() functions, with the media time mt. It then calls all the filters' MediaControl->Resume() function, since filters are started in a paused state.

You should call MmStart() only once for a graph. If at some point you need to change one of the filters, perform the following steps:

1. MmPause() the graph.
2. MmStop() the filter you want to remove.
3. Detach the filter.
4. Destroy the filter.
5. Create a new filter.
6. Attach the new filter.
7. MmStart() the new filter.
8. MmResume() the graph.

If you want to start the graph at a point other than the beginning of the stream (0), you should either seek to a position in the graph, and then start at that position, or start the graph at 0 and then seek to the position:

Example 1:

MmStart(graph, 0);
MmSeek(graph, t);

Example 2:

if(!MmSeek(graph, t))
MmStart(graph, t)

Returns:

0

Success.

-1

An error occurred.

Examples:

  // Assuming the graph is created, and whatever filters
  // were needed are added:

  MmStart(graph,0);

Classification:

Neutrino

See also:

MmPause(), MmResume(), MmStop()