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list

The list command determines the number and types of video and audio inputs. 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("list %s %s %s"), 
  lpszDeviceID, 
  lpszList, 
  lpszFlags
); 

Parameters

lpszDeviceID

Identifier of an MCI device. This identifier or alias is assigned when the device is opened.

lpszList

Flag that identifies the number and types of video and audio inputs. The following table lists device types that recognize the list command and the flags used by each type.

Value Meaning Meaning
digitalvideo audio algorithm
audio quality algorithm algorithm
audio stream
count
number index
still algorithm
still quality algorithm algorithm
video algorithm
video quality algorithm algorithm
video source
video stream
vcr audio source count
audio source number index
video source count
video source number index

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

Value Meaning
audio algorithm Specifies the command should retrieve audio algorithm names.
audio quality algorithm algorithm Specifies the command should retrieve quality levels associated with the specified algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
audio source count Returns the total number of audio inputs.
audio source number index Returns the type of audio input of source index.
audio stream Specifies the command should retrieve the names of the audio streams associated with the workspace. These strings (such as "English" or "German") are embedded in the file and identify the stream.
count Returns the number of options of the specified type.
number index Returns a string describing a specific option (as identified by index) of the specified option type. Index must be an integer between 1 and the value returned by "count".
still algorithm Specifies the command should retrieve still algorithm names.
still quality algorithm algorithm Specifies the command should retrieve quality levels associated with the specified still algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
video algorithm Specifies the command should retrieve video algorithm names.
video quality algorithm algorithm Specifies the command should retrieve quality levels associated with the specified video algorithm. If algorithm is "current", the quality level of the current algorithm is returned.
video source Specifies the command should return information about the video sources. When used with the "count" flag, it returns the number of video sources. When used with the "number" flag, it returns the type of a video source. MCI defines the following constants for type: "ntsc", "rgb", "pal", "secam", "svideo", and "generic". There might be more than one source of each type returned. The "generic" source type is used when more than one signal is allowed for that connector.
video source count Returns total number of video inputs.
video source number index Returns the type of video input of source index.
video stream Specifies the command should retrieve the names of video streams associated with the workspace. These strings (such as "funny ending" or "sad ending") are embedded in the file and identify the stream.

lpszFlags

Can be "wait", "notify", or "test". 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, either "video source" or "audio source" must be specified with either the "count" or "number" flags. If "count" is specified, the total number of inputs of video or audio is returned. If "number" is specified, the driver returns a type corresponding to the input. The type can be any one of the following: "tuner", "line", "svideo", "aux", or "generic". Typically, you should first query the VCR for the "count" and then use the count as the range for the "number" flag. The "source" numbers start from 1.

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

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