The data that the buffer or clipboard contains will be defined differently for each media driver.
The following formula is necessary to allocate memory for digital audio
clipboard operations:
(BitsPerSample/8) x (SamplesPerSecond) x (Channels) x (Seconds)
Therefore, if an application is to copy 20 seconds of a 16-bit, 44 kHz, mono file into the clipboard using the caller's buffer; 1,764,000 bytes ((16/8) x (44100) x (1) x (20)) must be allocated and placed in the pBuff field of the MCI_EDIT_PARMS structure. For MCI_CUT, MCI_COPY, and MCI_PASTE, if MCI_TO_BUFFER or MCI_FROM_BUFFER is passed in, then the pBuff field should contain a valid pointer.
MCI_STATUS_CLIPBOARD returns MCI_TRUE if digital audio is in the clipboard; otherwise it returns MCI_FALSE. MCI_CUT removes the specified range and places the data in the buffer or clipboard. The position of the media will either be the from position if MCI_FROM is specified or the previous position if MCI_FROM is not specified. If the buffer is not large enough for the data an MCIERR_INVALID_BUFFER is returned. The units of MCI_FROM and MCI_TO must be supplied in the currently selected time format. If neither MCI_FROM or MCI_TO are specified, the operation will start from the current file position and continue to the end of the file. If audio data is already in the clipboard, it will be overwritten.
Note: The clipboard contents are emptied before the cut occurs.
MCI_COPY copies the specified range and places the data in the buffer or clipboard. The position of the media remains the same as it was before the copy operation.
MCI_PASTE deletes the selected range if the differences between the from and to position are greater than zero, then inserts the data provided in the buffer or clipboard. The media position will be at the end of what was pasted into the file. If neither MCI_FROM or MCI_TO are specified, MCI_PASTE inserts the clipboard contents at the current position. MCI_CONVERT_FORMAT converts the data that was in the clipboard to the destination file format. The following data format conversions can be performed:
Note: The MCI_CONVERT_FORMAT flag supports only the Pulse Code Modulation (PCM) format. The data format conversion can take a while to complete. If the notify flag is specified, the application is notified when the conversion is completed.
The following code fragment shows an example of the use of MCI_COPY and MCI_PASTE.
ULONG weMciCopy( HWND hwnd, ULONG ulMarkedStartBytes,
ULONG ulMarkedEndBytes, USHORT usDeviceID )
{
ULONG ulFlags;
MCI_EDIT_PARMS mcieditstr;
ULONG ulResult;
ulResult = 0L;
/*
* First, set all fields of the MCI_EDIT_PARMS structure to 0.
*/
memset( &mcieditstr, '\0', sizeof(MCI_EDIT_PARMS) );
/*
* The flags are NOTIFY, FROM, and TO.
*/
ulFlags = 0L;
ulFlags |= MCI_NOTIFY |
MCI_FROM |
MCI_TO;
mcieditstr.ulCallback = (ULONG)hwnd;
/*
* Set the from and to items to the beginning and end
* of the selected area.
*/
mcieditstr.ulFrom = ulMarkedStartBytes;
mcieditstr.ulTo = ulMarkedEndBytes;
ulResult = mciSendCommand( usDeviceID,
MCI_COPY,
ulFlags,
(ULONG)&mcieditstr,
0 );
return( ulResult );
{
ULONG weMciPaste( HWND hwnd, ULONG ulMarkedStartBytes,
ULONG ulMarkedEndBytes, USHORT usDeviceID )
{
ULONG ulFlags;
MCI_EDIT_PARMS mcieditstr;
ULONG ulResult;
ulResult = 0L;
/*
* First, set all fields of the MCI_EDIT_PARMS structure to 0.
*/
memset( &mcieditstr, '\0', sizeof(MCI_EDIT_PARMS) );
mcieditstr.ulCallback = (ULONG)hwnd;
ulFlags = 0L;
/*
* If there is an area of wave selected, then the flags are NOTIFY,
* FROM, TO, and CONVERT_FORMAT.
*/
if( ulMarkedEndBytes > ulMarkedStartBytes )
{
ulFlags |= MCI_NOTIFY |
MCI_FROM |
MCI_TO |
MCI_CONVERT_FORMAT;
/*
* Set the from and to items to the beginning and end
* of the selected area.
*/
mcieditstr.ulFrom = ulMarkedStartBytes;
mcieditstr.ulTo = ulMarkedEndBytes;
}
else
{
/*
* Otherwise, nothing in the wave is selected so the flags are
* only NOTIFY and CONVERT_FORMAT.
*/
ulFlags |= MCI_NOTIFY |
MCI_CONVERT_FORMAT;
/*
* Because this is a paste operation without FROM/TO,
* we have to SEEK so that the media position is set
* to the place that we want to paste.
*/
if( ulResult = weMciCall( hwnd,
MCI_SEEK ) )
return( ulResult );
}
ulResult = mciSendCommand( usDeviceID,
MCI_PASTE,
ulFlags,
(ULONG)&mcieditstr,
0 );
return( ulResult );
{
The following is an example of using the command string interface with editing commands to create a repeating sound.
open test.wav alias a wait copy a from 0 to 3000 wait seek a to end paste a wait paste a wait paste a wait