MCI_GETDEVCAPS
The MCI_GETDEVCAPS
command retrieves static information about a device. All devices recognize this
command. The parameters and flags available for this command depend on the
selected device. Information is returned in the dwReturn member of the
structure identified by lpCapsParms.
MCIERROR mciSendCommand(MCIDEVICEID wDeviceID,
MCI_GETDEVCAPS,
DWORD dwFlags, (DWORD)
(LPMCI_GETDEVCAPS_PARMS) lpCapsParms);
Parameters
wDeviceID
Device
identifier of the MCI device that is to receive the command message.
dwFlags
MCI_NOTIFY,
MCI_WAIT, or, for digital-video and VCR devices, MCI_TEST. For information
about these flags, see The Wait, Notify, and Test Flags.
lpCapsParms
Address of an
MCI_GETDEVCAPS_PARMS
structure.
Return Values
Returns zero
if successful or an error otherwise.
Remarks
The following
additional standard and command-specific flags apply to all devices supporting MCI_GETDEVCAPS:
MCI_GETDEVCAPS_COMPOUND_DEVICE
The dwReturn
member is set to TRUE if the device uses data storage that must be explicitly
opened and closed; it is set to FALSE otherwise.
MCI_GETDEVCAPS_DEVICE_TYPE
The dwReturn
member is set to one of the values listed in Constants: Device Types.
MCI_GETDEVCAPS_HAS_AUDIO
The dwReturn
member is set to TRUE if the device has audio output; it is set to FALSE
otherwise.
MCI_GETDEVCAPS_HAS_VIDEO
The dwReturn
member is set to TRUE if the device has video output; it is set to FALSE
otherwise. For example, the member is set to TRUE for devices that support the
videodisc command set.
MCI_GETDEVCAPS_ITEM
Specifies
that the dwItem member of the MCI_GETDEVCAPS_PARMS structure contains one of
the following constants:
MCI_GETDEVCAPS_CAN_EJECT
The dwReturn
member is set to TRUE if the device can eject the media; otherwise, it is set
to FALSE.
MCI_GETDEVCAPS_CAN_PLAY
The dwReturn
member is set to TRUE if the device can play the media; otherwise, it is set to
FALSE. If a device specifies TRUE, it implies the device supports the MCI_PAUSE and MCI_STOP commands as well as the MCI_PLAY command.
MCI_GETDEVCAPS_CAN_RECORD
The dwReturn
member is set to TRUE if the device supports recording; otherwise, it is set to
FALSE. If a device specifies TRUE, it implies the device supports the MCI_PAUSE
and MCI_STOP commands as well as the MCI_RECORD command.
MCI_GETDEVCAPS_CAN_SAVE
The dwReturn
member is set to TRUE if the device can save a file; otherwise, it is set to
FALSE.
MCI_GETDEVCAPS_USES_FILES
The dwReturn
member is set to TRUE if the device requires a filename; it is set to FALSE
otherwise. Only compound devices use files.
The following
flags can be specified in the dwItem member of MCI_GETDEVCAPS_PARMS for the digitalvideo
device type:
MCI_DGV_GETDEVCAPS_CAN_FREEZE
The dwReturn
member is set to TRUE if the device can freeze frames; otherwise, it is set to
FALSE.
MCI_DGV_GETDEVCAPS_CAN_LOCK
The dwReturn
member is set to TRUE if the device can lock; otherwise, it is set to FALSE.
MCI_DGV_GETDEVCAPS_CAN_REVERSE
The dwReturn
member is set to TRUE if the device can play in reverse; otherwise, it is set
to FALSE.
MCI_DGV_GETDEVCAPS_CAN_STR_IN
The dwReturn
member is set to TRUE if the device can stretch input; otherwise, it is set to
FALSE.
MCI_DGV_GETDEVCAPS_CAN_STRETCH
The dwReturn
member is set to TRUE if the device can stretch an image; otherwise, it is set
to FALSE.
MCI_DGV_GETDEVCAPS_CAN_TEST
The dwReturn
member is set to TRUE if the device can perform tests; otherwise, it is set to
FALSE.
MCI_DGV_GETDEVCAPS_HAS_STILL
The dwReturn
member is set to TRUE if the device can display still images; otherwise, it is
set to FALSE.
MCI_DGV_GETDEVCAPS_MAX_WINDOWS
The dwReturn
member is set to the maximum number of windows that the device can handle
simultaneously.
MCI_DGV_GETDEVCAPS_MAXIMUM_RATE
The dwReturn
member is set to the maximum play rate for the device, in frames per second.
MCI_DGV_GETDEVCAPS_MINIMUM_RATE
The dwReturn
member is set to the minimum play rate for the device, in frames per second.
MCI_DGV_GETDEVCAPS_PALETTES
The dwReturn
member is set to TRUE if the device can return a palette handle; otherwise, it
is set to FALSE.
The following
flags can be specified in the dwItem member of MCI_GETDEVCAPS_PARMS for the vcr device
type:
MCI_GETDEVCAPS_CLOCK_INCREMENT_RATE
The dwReturn
member is set to the number of increments per second.
MCI_VCR_GETDEVCAPS_CAN_DETECT_LENGTH
The dwReturn
member is set to TRUE if the device is capable of detecting the length of the
media; otherwise, it is set to FALSE.
MCI_VCR_GETDEVCAPS_CAN_FREEZE
The dwReturn
member is set to TRUE if the device is capable of freezing the output image;
otherwise, it is set to FALSE.
MCI_VCR_GETDEVCAPS_CAN_MONITOR_SOURCES
The dwReturn
member is set to TRUE if the device is capable of monitoring sources;
otherwise, it is set to FALSE.
MCI_VCR_GETDEVCAPS_CAN_PREROLL
The dwReturn
member is set to TRUE if the device is capable of preroll; otherwise, it is set
to FALSE.
MCI_VCR_GETDEVCAPS_CAN_PREVIEW
The dwReturn
member is set to TRUE if the device is capable of previews; otherwise, it is
set to FALSE.
MCI_VCR_GETDEVCAPS_CAN_REVERSE
The dwReturn
member is set to TRUE if the device is capable of playing in reverse;
otherwise, it is set to FALSE.
MCI_VCR_GETDEVCAPS_CAN_TEST
The dwReturn
member is set to TRUE if the device is capable of testing; otherwise, it is set
to FALSE.
MCI_VCR_GETDEVCAPS_HAS_CLOCK
The dwReturn
member is set to TRUE if the device supports an external clock; otherwise, it
is set to FALSE.
MCI_VCR_GETDEVCAPS_HAS_TIMECODE
The dwReturn
member is set to TRUE if device has timecode capability or if this capability
is unknown; otherwise, it is set to FALSE.
MCI_VCR_GETDEVCAPS_NUMBER_OF_MARKS
The dwReturn
member is set to the number of marks (99).
MCI_VCR_GETDEVCAPS_SEEK_ACCURACY
The dwReturn
member is set to the seek accuracy of the device.
The following
flags can be specified in the dwItem member of MCI_GETDEVCAPS_PARMS for the overlay
device type:
MCI_OVLY_GETDEVCAPS_CAN_FREEZE
The dwReturn
member is set to TRUE if the device can freeze the image; otherwise, it is set
to FALSE.
MCI_OVLY_GETDEVCAPS_CAN_STRETCH
The dwReturn
member is set to TRUE if the device can stretch the image to fill the frame;
otherwise, it is set to FALSE.
MCI_OVLY_GETDEVCAPS_MAX_WINDOWS
The dwReturn
member is set to the maximum number of windows that the device can handle
simultaneously.
The following
flags can be specified in the dwItem member of MCI_GETDEVCAPS_PARMS for the videodisc
device type:
MCI_VD_GETDEVCAPS_CAN_REVERSE
The dwReturn
member is set to TRUE if the videodisc player can play in reverse; otherwise,
it is set to FALSE. Some players can play CLV discs in reverse as well as CAV
discs.
MCI_VD_GETDEVCAPS_CAV
When combined
with other items, specifies that the return information applies to CAV format
videodiscs. This is the default if no videodisc is inserted.
MCI_VD_GETDEVCAPS_CLV
When combined
with other items, specifies that the return information applies to CLV format
videodiscs.
MCI_VD_GETDEVCAPS_FAST_RATE
The dwReturn
member is set to the standard fast play rate in frames per second.
MCI_VD_GETDEVCAPS_NORMAL_RATE
The dwReturn
member is set to the normal play rate in frames per second.
MCI_VD_GETDEVCAPS_SLOW_RATE
The dwReturn
member is set to the standard slow play rate in frames per second.
The following
flags can be specified in the dwItem member of MCI_GETDEVCAPS_PARMS for the waveaudio
device type:
MCI_WAVE_GETDEVCAPS_INPUT
The dwReturn
member is set to the total number of waveform input (recording) devices.
MCI_WAVE_GETDEVCAPS_OUTPUT
The dwReturn
member is set to the total number of waveform output (playback) devices.
See Also