seek
The seek
command moves to the specified position and stops. CD audio, digital-video,
MIDI sequencer, VCR, videodisc, and waveform-audio devices recognize this
command.
wsprintf(lpstrCommand, "seek %s %s %s",
lpszDeviceID, lpszSeekFlags,
lpszFlags);
Parameters
lpszDeviceID
Identifier of
an MCI device. This identifier or alias is assigned when the device is opened.
lpszSeekFlags
Flag for
moving to a specified position. The following table lists device types that
recognize the seek command and the flags used by each type:
|
cdaudio |
to end |
to start |
|
digitalvideo |
to end |
to start |
|
sequencer |
to end |
to start |
|
vcr |
at time |
to end |
|
videodisc |
reverse |
to position |
|
waveaudio |
to end |
to start |
The following
table lists the flags that can be specified in the lpszSeekFlags parameter
and their meanings:
|
at time |
Indicates
when the device should begin performing this command, or, if the device has
been cued, when the cued command begins. For more information, see the cue command. |
|
mark mark_num |
Seeks to
the relative mark indicated by mark_num, which must be a positive
integer value. Marks are signals written to the VCR tape using the mark command and are used for
high-speed searching. |
|
reverse |
Indicates
that the seek direction on VCRs and CAV videodiscs is backward. This flag is
invalid if the to flag is specified. For VCRs, this flag must be used with
the mark flag. |
|
to end |
Seeks to
the end of the content. |
|
to position |
Specifies
the position to stop the seek. For cdaudio devices, MCI returns an
out-of-range error if the specified position is greater than the length of the
disc. |
|
to start |
Seeks to
the start of the content. |
lpszFlags
Can be
wait , notify , or both. For digital-video and VCR devices, test can also
be specified. For more information about these flags, see The Wait, Notify,
and Test Flags.
Return Values
Returns zero
if successful or an error otherwise.
Remarks
Before
issuing any commands that use position values, you should set the desired time
format by using the set
command.
Digital-video
devices support two seek modes, which you can change by using the set
command. The seek exactly on mode causes the seek command to move to the
specified frame. The seek exactly off mode causes the seek command to move to
the closest key frame prior to the specified frame.
If a CD audio
device is playing when the seek command is issued, playback is stopped.
When the seek command is issued with a videodisc device, the device
searches using fast forward or fast reverse with video and audio off.
When the seek
command is issued with a waveform-audio device, the behavior depends on the
sample size. If the sample size is 16 bits or greater, seek moves to the
beginning of the nearest sample when a specified position does not coincide
with the start of a sample.
The following
command seeks to the start of the media file associated with the mysound
device:
seek mysound to start
See Also