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setvideo

The setvideo command sets values associated with video playback and capture. Digital-video and VCR devices recognize this command.

To send this command, call the mciSendString function with the lpszCommand parameter set as follows.

_stprintf_s(
  lpszCommand, 
  TEXT("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.

Value Meaning Meaning
digitalvideo algorithm algorithm
bitsperpel to count
brightness to factor
clocktime
color to factor
contrast to factor
gamma to value
halftone
input
key color to r:g:b
key index to index
off
on
output
over duration
palette color color over index
   to newrgb
palette handle to handle
quality descriptor
record frame rate to rate
record on
record off
sharpness to factor
source to source number value
still algorithm algorithm
still quality descriptor
stream to number
tint to factor
vcr off
on
monitor to type number number
record off
record track track_number off
record on
record track track_number on
source to type number number
track track_number off
track track_number on

The following table lists the flags that can be specified in the lpszVideo parameter and their meanings.

Value Meaning
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
on
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
record off
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 Flags.

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.

Requirements

  Windows NT/2000/XP: Included in Windows NT 3.1 and later.
  Windows 95/98/Me: Included in Windows 95 and later.

See Also

MCI, MCI Command Strings, capture, list, put, quality, record, reserve, RGB, set, setaudio, window

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