setvideo
The setvideo
command sets values associated with video playback and capture. Digital-video
and VCR devices recognize this command.
wsprintf(lpstrCommand, "setvideo %s %s
%s", lpszDeviceID, lpszVideo,
lpszFlags);
Parameters
lpszDeviceID
Identifier of
an MCI device. This identifier or alias is assigned when the device is opened.
lpszVideo
Flag for
video playback and capture. The following table lists device types that
recognize the setvideo command and the flags used by each type:
|
digitalvideo |
algorithm algorithm |
over duration |
|
vcr |
off |
record on |
The following
table lists the flags that can be specified in the lpszVideo parameter
and their meanings:
|
algorithm algorithm |
Specifies a
video compression algorithm for use by a subsequent reserve or record command. Algorithms
supported by a device are device specific. MCI defines the constants mpeg
and h261 for algorithm. If the
specified algorithm conflicts with the current file format, the file format
is changed to the default format for the algorithm. |
|
bitsperpel
to count |
Sets the
number of bits per pixel for saving data with the capture or record command. |
|
brightness
to factor |
Sets the
video brightness level. |
|
clocktime |
Indicates
that the time specified in the over flag is in milliseconds. The time is
absolute and not in step with the playing of the workspace. |
|
color to factor |
Sets the
color-saturation level. |
|
contrast to
factor |
Sets the
video-contrast level. |
|
gamma to value |
Specifies
the gamma correction exponent multiplied by 1000. For example, to specify an
exponent of 2.2, use 2200 for value. A gamma value of 1.0 (1000)
indicates no gamma correction is applied. Gamma correction adjusts the
mapping between the intensity encoded in the presentation source and the displayed
brightness. |
|
halftone |
Causes the
halftone palette to be used instead of the default palette. This flag is
recognized only by the MCIAVI digital-video driver. |
|
input |
Modifies
the brightness , color , contrast , gamma , sharpness , or tint flag
so that it affects the input signal and modifies what is recorded. If
possible, this is the default when monitoring the input. |
|
key color
to r:g:b |
Sets the
key color. The r:g:b variable is a Windows RGB value. Colons (:) separate
the individual red, green, and blue values. |
|
key index
to index |
Sets the
key index. The index variable is a physical palette index. |
|
monitor to type
number number |
Controls
which source input will be passed to the VCR output, without changing the
recording source input selection. Type can be output , or one of the
valid input sources. If number is not specified, then the first input of
that type is chosen. |
|
off |
Enables or
disables display of video. Disabling video sets the pixels in the put destination rectangle
(or its default, the client region of the current window) to a solid color.
It has no effect on the frame buffer. The video
source, whether the workspace or an external input, might continue to store
new images in the frame buffer. They are not displayed until video is
enabled. You can use the window state command to hide the window. The
default is setvideo on . |
|
output |
Modifies
the brightness , color , contrast , gamma , sharpness , or tint flag
so that it modifies only the displayed signal and not what is recorded. If
possible, this is the default when monitoring a file. |
|
over duration |
Specifies
how long it should take to make a change that uses a factor variable.
The units for duration are in the current time format. Changes occur
in step with the playing of the workspace. When playing is suspended, the
change is also suspended until the play continues. If over is not used or
not supported, the change occurs immediately. |
|
palette
color color over index to newrgb |
Sets a new
palette color. The color and palette index to be changed are specified by the
color and index parameters; the new color is specified by newrgb.
This flag is recognized only by the MCIAVI digital-video driver. |
|
palette
handle to handle |
Specifies
the handle to a palette the device must use for rendering. This item is
supported only by devices that use palettes. If handle is zero, the
default palette is used. Digital-video
devices should not free the palette passed with this command. Applications
should free it after they close the device. |
|
quality descriptor |
Specifies
the characteristics of the video compression performed when video is recorded
to a file. All devices support the three descriptors: low , medium , and
high . The default is device specific. The significance of these names
depends on the algorithm and the device. Devices might define additional
descriptor names. The quality command can be used to define additional descriptor
names. If the
algorithm flag is not used, the descriptor applies to the current
algorithm. |
|
record
frame rate to rate |
Sets the
recording for motion video. The recording rate is specified in units
of frames per second multiplied by 1000. For example, the NTSC frame rate of
29.97 frames per second is represented as 29970. |
|
record on |
Enables or
disables recording of video data. Recording video data is the default. |
|
record
track track_number off |
Clears the
video-source selection so that no video will be recorded with the next record command. Track allows
independent track selection. If track is not specified, a default value of
1 is assumed. It might be necessary to first issue a set assemble record off
command before the video recording can be turned off. |
|
record
track track_number on |
Selects the
video source to be recorded with the next record command. Track allows
independent track selection. Track 2 corresponds to the PCM track in Hi8. If
track is not specified, a default of 1 is assumed. |
|
sharpness
to factor |
Sets the
video sharpness level. |
|
source to source
number value |
Sets the
source of the video input. This usually corresponds to external connectors.
The constants defined for source include rgb , pal , ntsc ,
svideo , and secam . If more than one input of the specified type exists,
the optional number value indicates the desired input. For example, setvideo
source to ntsc number 2 specifies the second NTSC input. If to source
is omitted, then the absolute source is used as defined by the list video source command. |
|
source to type
number number |
Selects the
video source to be recorded on the tape. Type must be tuner , line ,
svideo , aux , generic , mute , or rgb . |
|
still
algorithm algorithm |
Specifies
the still image compression algorithm used by the capture command. Every device
must support an algorithm of none , which means no compression. This
is the default. In this case, digital-video devices save still images as RGB format device-independent
bitmaps. Devices might also support a device-specific list of additional
algorithms. |
|
still
quality descriptor |
Specifies
the characteristics of the still-image compression performed while capturing
a still image. All devices support the descriptors low , medium , and
high . The default is device specific. If the
algorithm flag is not used, the descriptor applies to the current
algorithm. The quality command can be used to
define other descriptor names. |
|
stream to number |
Specifies
the video stream played back from the workspace. If the stream is not
specified and a default stream is not defined by the file format, then the
physically first interleaved video stream is played. |
|
tint to
factor |
Sets the
image tint. Typically, this adjustment is modeled after the tint control of
many color television sets, with 250 meaning green, 750 meaning red, and 0
(or 1000) meaning blue. The nominal value is always 500. |
|
track track_number
off |
Disables an
individual video track. |
|
track track_number
on |
Enables an
individual video track. |
lpszFlags
Can be
wait , notify , test , or a combination of these. For more information about
these flags, see The Wait, Notify, and Test Flags4FW.04J.
Return Values
Returns zero
if successful or an error otherwise.
Remarks
For VCR
devices, using setvideo with a flag that turns off an individual track
( track track_number off ) might cause your application to receive a status
message indicating that the command could not be carried out. Some VCRs can
turn off only combinations of tracks, not individual tracks; for example, the
first audio track and a video track of a video cassette. In this case, simply
use setaudio
and setvideo to continue to turn off the other tracks that make up the
combination. The driver will turn off the tracks when it receives the command
to turn off the last track in the combination.
See Also