int32 DSSetClock (DSStreamCBPtr streamCBPtr, uint32
newStreamClock)
DSSetClock() sets the
clock by resetting the DataStreamer clock offset to the specified value.
DSSetClock() also sets to TRUE the
STRM_CLOCK_VALID and STRM_CLOCK_WAS_VALID flags
of the streamFlags field in the stream context block of the
specified stream. These flags indicate, respectively, that the current
clock time is correct and that the clock has been set at least once since
the stream was opened or since the last time it was stopped.
Clock time in the DataStreamer is measured in standard Portfolio audio clock ticks (the DataStreamer does not change the rate of the audio clock or the duration of audio ticks). Since the DataStreamer does not own the audio clock, however, external tasks can affect the DataStreamer clock by altering the state of the audio clock. (By default, the audio clock is set to 240 ticks per second.)
Since the DataStreamer and acquisition threads determine stream
positioning and data flushing by the DataStreamer clock, resetting the
clock can affect the loading of streamed data chunks adversely. The
DataStreamer clock is normally reset only when a new stream is opened.
Streams can be started and stopped without requiring the DataStreamer
clock to be reset (see DSStartStream() and
DSStopStream()).
streamCBPtr
newStreamClock
streamCBPtr.
kDSNoErr
kDSNotRunning
DSGetClock, DSStartStream, DSStopStream,
OwnAudioClock