一些多媒体的技巧

Miu.C

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Miu.C

下面的定义以及代码可以实现播放一个Wav文件。
Private Declare Function mciExecute Lib "winmm.dll" (ByVal strFilename As String) As Integer

Dim lngResult As Long
lngResult = mciExecute(&quotlay C:\Windows\Media\logoff.wav")

Miu.C

声明：
Declare Function MCISendString& Lib "MMSYSTEM" (ByVal LPSTRCOMMAND$, ByVal LPSTRRETURNSTR As Any, ByVal WRETURNLEN%, ByVal HCALLBACK%)
开始播放：
R% = MCISendString&("OPEN EXAMPLE.MID TYPE SEQUENCER ALIAS NN", 0&, 0, 0)
R% = MCISendString&(&quotLAY NN FROM 0", 0&, 0, 0)
R% = MCISendString&("CLOSE ANIMATION", 0&, 0, 0)
停止：
R% = MCISendString&("OPEN EXAMPLE.MID TYPE SEQUENCER ALIAS NN", 0&, 0, 0)
R% = MCISendString&("STOP NN", 0&, 0, 0)
R% = MCISendString&("CLOSE ANIMATION", 0&, 0, 0)
其中EXAMPLE.MID 为播放的文件，NN为自定义名称标志。

Miu.C

WAV 文件基本信息包括如是否立体声，采样频率等。
声明：
Public Const RIFF_ID = 1179011410
Public Const RIFF_WAVE = 1163280727
Public Const RIFF_FMT = 544501094
'Typical header of a simple RIFF WAVE file
Public Type WAVInfo
  Riff_Format As Long
  chunk_size As Long
  ChunkID As Long fmt As Long
  Wave_Format As Integer
  Channels As Integer '0 = 单声道, 1 = 立体声
  SamplesPerSecond As Long
  AverageBytesPerSecond As Long '11.025kHz, 22.05kHz, 等
  BlockAlign As Integer 'Size of blocks for low level playback
End Type
函数：
Public Function GetWaveInfo(Byval filename As String, Byref w As WAVInfo) _
As Boolean

Dim ff As Integer
ff = FreeFile

On Error GoTo ehandler
Open filename For Binary Access Read As #ff

On Error GoTo ehandler_fo
Get #ff, , w
Close #ff

On Error GoTo ehandler

If w.Riff_Format = RIFF_ID And w.ChunkID = _
RIFF_WAVE And w.fmt = RIFF_FMT Then

GetWaveInfo = True
Else
GetWaveInfo = False
End If

Exit Function

ehandler_fo:
Close #ff
ehandler:
GetWaveInfo = False
End Function

Miu.C

Public Declare Function sndPlaySound& Lib "winmm.dll" Alias"sndPlaySoundA" (ByVal lpszSoundName As String, ByVal uFlags As Long)
Global Const SND_SYNC = &H0
Global Const SND_ASYNC = &H1
Global Const SND_NODEFAULT = &H2
Global Const SND_LOOP = &H8
Global Const SND_NOSTOP = &H10


Sub PlayWav(SoundName As String)
Dim tmpSoundName As String
Dim wFlags%, X%
tmpSoundName = pathWavFiles & SoundName
wFlags% = SND_ASYNC Or SND_NODEFAULT
X% = sndPlaySound(tmpSoundName, wFlags%)

Miu.C

VB 提供的方法使我们可以很容易地使用资源文件中的字符、图片等资源。我们可以用以下方法播放资源文件中的 wav 声音：
首先，在你的资源文件的源文件 (RC) 文件加入下面一行：
MySound WAVE c:\music\vanhalen.wav
然后将其编译为 RES 文件。
最后使用下面的声明及代码：
Private Declare Function PlaySound Lib _ "winmm.dll" Alias &quotlaySoundA" ( _ ByVal lpszName As String, _ ByVal hModule As Long, _ ByVal dwFlags As Long) As Long Private
Const SND_ASYNC& = &H1
Private Const SND_NODEFAULT& = &H2
Private Const SND_RESOURCE& = &H40004
Dim hInst As Long
Dim sSoundName As String
Dim lFlags As Long
Dim lRet As Long Private
Sub Command1_Click() hInst = App.hInstance
sSoundName = "MySound"
lFlags = SND_RESOURCE + SND_ASYNC + _ SND_NODEFAULT
lRet = PlaySound(sSoundName, hInst, lFlags)
End Sub

Miu.C

Declare Function mciSendString& Lib "MMSYSTEM" (ByVal pstrCommand$,
ByVal lpstrReturnStr As Any, ByVal wReturnLen%, ByVal CallBack%)

'Add this code to the appropriate event:

Dim CmdStr$
Dim ReturnVal&

    ' Modify path and filename as necessary
    CmdStr$ = "play G:\VFW_CINE\AK1.AVI"
    ReturnVal& = mciSendString(CmdStr$, 0&, 0, 0&)

' To play the AVI 'fullscreen' append to CmdStr$:

    CmdStr$ = "play G:\VFW_CINE\AK1.AVI fullscreen"

Miu.C

最后：你要实在嫌麻烦不如用自带的MediaPlayer控件。