使用 VBA 在 PowerPoint 中的特定幻灯片上淡化背景媒体的音量 [英] Fade volume of background media on specific slide in PowerPoint using VBA

问题描述

我有一个 PowerPoint，它以自动播放的媒体文件开头.第一张幻灯片被编程为在 20 秒后转换，同时音乐一直播放.我希望它在幻灯片放映期间继续播放，但在第二张幻灯片出现后逐渐降低音量，并在演示的其余部分保持这种状态.我看过这个 Powerpoint 在宏中更改音效音量 但是它似乎不能满足我的需求.

I have a PowerPoint which begins with a a media file automatically playing. The first slide is programmed to transition after 20 seconds, all the while the music keeps playing. I would like for it to keep playing for the duration of the slideshow, but fade to a lower volume once the second slide appears and remain that way for the rest of the presentation. I've looked at this Powerpoint change sound effect volume in macro but it doesn't seem to satisfy my needs.

我试过了:

Sub fadeVolSlideChange(ByVal ShowPos As SlideShowWindow)
    Dim ShowPos As Integer
    Dim bkgMusic As Shape
    Dim Step As Long
    
    ShowPos = ShowPos.View.CurrentShowPosition
    Set bkgMusic = ActiveWindow.Selection.ShapeRange(1)

    If ShowPos = 2 Then
        Set Step = 0.05
        For i = 1 To 0.5
            With bkgMusic.MediaFormat
                .Volume = i
                .Muted = False
            End With
            i = i - Step
            Application.Wait (Now + 0.0000025)
        Next i
    End If

End Sub

没有运气.想法?

这是最新的编辑(仍然没有运气让它工作):

Here's the latest edit (still no luck getting it to work):

Sub OnSlideShowPageChange()
    Dim i As Integer
    Dim bkgMusic As Shape
    Dim bkgVol As Long
    Dim inc As Long
    i = ActivePresentation.SlideShowWindow.View.CurrentShowPosition
    Set bkgMusic = ActivePresentation.Slides(1).Shapes("Opening Theme")
    
    If i = 1 Then
        'Do nothing
    ElseIf i <> 1 Then
        inc = 0.05
        For bkgVol = 1 To 0.1
            With bkgMusic.MediaFormat
                .Volume = bkgVol
                .Muted = False
            End With
            bkgVol = bkgVol - inc
            Application.Wait (Now + TimeValue("0:00:01"))
        Next bkgVol
    End If
    
End Sub

推荐答案

这个几乎有效，但 PPT 最终让我们失望.运行后，声音文件的音量降低了，但在幻灯片放映过程中没有变化.

This almost works, but PPT shoots us down in the end. After it runs, the volume of the sound file has been reduced, but it doesn't change during the slideshow.

Sub OnSlideShowPageChange()
    Dim i As Integer
    Dim bkgMusic As Shape
    ' This needs to be single, not Long
    Dim bkgVol As Single
    Dim inc As Long
    Dim lCounter As Long
    
    i = ActivePresentation.SlideShowWindow.View.CurrentShowPosition

    Set bkgMusic = ActivePresentation.Slides(1).Shapes("Opening Theme")
    
    If i = 2 Then
        inc = 0.05
        ' Changing the value by fractions so must be a single, not a long, and
        ' decreasing the value requires Step and a negative number:
        For bkgVol = 1 To 0.1 Step -0.1
            With bkgMusic.MediaFormat
                .Volume = bkgVol
                .Muted = False
            End With
            'bkgVol = bkgVol - inc
            ' Application.Wait is not supported in PPT
            'Application.Wait (Now + TimeValue("0:00:01"))
            WaitForIt
            SlideShowWindows(1).View.GotoSlide (2)
        Next bkgVol
    End If
    
End Sub


Sub WaitForIt()

Dim x As Long

For x = 1 To 1000000
    DoEvents
Next
    'MsgBox "Done waiting"
End Sub

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