c# - 像Windows Volume Mixer一样的VU Meter

我正在开发一个屏幕录制软件，它具有音量控制。我下面粘贴的代码是我如何控制音量的方法。

static class NativeMethods
    {
        [DllImport("winmm.dll")]
        public static extern int waveOutGetVolume(IntPtr hwo, out uint dwVolume);

        [DllImport("winmm.dll", EntryPoint = "waveOutSetVolume")]
        public static extern int WaveOutSetVolume(IntPtr hwo, uint dwVolume);

        [DllImport("winmm.dll", SetLastError = true)]
        public static extern bool PlaySound(string pszSound, IntPtr hmod, uint fdwSound);
    }


//Event for handling volume control
    private void VolumeSlider(object sender, RoutedPropertyChangedEventArgs<double> e)
    {
        // Calculate the volume that's being set
     int NewVolume = ((ushort.MaxValue / 10) * (int)slider.Value);
        // Set the same volume for both the left and the right channels
        uint NewVolumeAllChannels = (((uint)NewVolume & 0x0000ffff) | ((uint)NewVolume << 16));
        // Set the volume
        NativeMethods.WaveOutSetVolume(IntPtr.Zero, NewVolumeAllChannels);
    }

通过在Windows上查看Volume Mixer，我可以看到它设置了应用程序的音量而不是设备的音量。这很棒，因为仅更改应用程序的音量会更改其录制的视频的音量。



现在，我想知道是否可以像Windows Volume Mixer中那样为应用程序的卷创建VU Meter。我尝试使用NAudio达到此效果，但不确定如何或是否可以实现。我对其他API持开放态度。

编辑:我不是在问如何改变音量...我只需要一个功能VU Meter像在搅拌机上的。

最佳答案

不想让这个问题没有答案，以防有人偶然发现。基本上@RickLiddle评论有答案。我将根据回答给出修改后的代码，并尝试进行解释。试图学习这一点，我对NAudio＆CSCore非常熟悉，因此，如果您需要进一步的帮助，请不要犹豫。

class PeakClass
{
    static int CurrentProcessID = 0000;

    private static void Main(string[] args)
    {
        //Basically gets your default audio device and session attached to it
        using (var sessionManager = GetDefaultAudioSessionManager2(DataFlow.Render))
        {
            using (var sessionEnumerator = sessionManager.GetSessionEnumerator())
            {
                //This will go through a list of all processes uses the device
                //the code got two line above.
                foreach (var session in sessionEnumerator)
                {
                    //This block of code will get the peak value(value needed for VU Meter)
                    //For whatever process you need it for (I believe you can also check by name
                    //but I found that less reliable)
                    using (var session2 = session.QueryInterface<AudioSessionControl2>())
                    {
                        if(session2.ProcessID == CurrentProcessID)
                        {
                            using (var audioMeterInformation = session.QueryInterface<AudioMeterInformation>())
                            {
                                Console.WriteLine(audioMeterInformation.GetPeakValue());
                            }
                        }
                    }

                   //Uncomment this block of code if you need the peak values
                   //of all the processes
                   //
                    //using (var audioMeterInformation = session.QueryInterface<AudioMeterInformation>())
                    //{
                    //    Console.WriteLine(audioMeterInformation.GetPeakValue());
                    //}
                }
            }
        }
    }

    private static AudioSessionManager2 GetDefaultAudioSessionManager2(DataFlow dataFlow)
    {
        using (var enumerator = new MMDeviceEnumerator())
        {
            using (var device = enumerator.GetDefaultAudioEndpoint(dataFlow, Role.Multimedia))
            {
                Console.WriteLine("DefaultDevice: " + device.FriendlyName);
                var sessionManager = AudioSessionManager2.FromMMDevice(device);
                return sessionManager;
            }
        }
    }
}