C# BASS音频库 EQ设置效果

上篇简单的介绍了 BASS的播放和频谱的使用，这篇文章主要讲 BASS插件的音效设置。直接上代码。
效果图：
代码：
 1 using System;
 2 using System.Windows.Forms;
 3 using Un4seen.Bass;
 4 
 5 namespace WindowsFormsApp4
 6 {
 7     public partial class Form1 : Form
 8     {
 9         public Form1()
10         {
11             InitializeComponent();
12         }
13         string file = "";
14         int _stream = 0;
15         private void Form1_Load(object sender, EventArgs e)
16         {
17             bool r = Bass.BASS_Init(-1, 48000, BASSInit.BASS_DEVICE_CPSPEAKERS, this.Handle);
18 
19             if (!r)
20             {
21                 MessageBox.Show("出错了，" + Bass.BASS_ErrorGetCode().ToString());
22                 return;
23             }
24         }
25 
26         /// <summary>
27         /// 打开文件
28         /// </summary>
29         /// <param name="sender"></param>
30         /// <param name="e"></param>
31         private void btnOpen_Click(object sender, EventArgs e)
32         {
33             OpenFileDialog o = new OpenFileDialog();
34             if (o.ShowDialog() == DialogResult.OK)
35             {
36                 file = o.FileName;
37 
38                 if (_stream != 0)
39                     Bass.BASS_ChannelStop(_stream);
40 
41                 //第一个参数是文件名，
42                 //第二个参数是文件流开始位置，
43                 //第三个是文件流长度 0为使用文件整个长度，
44                 //最后一个是流的创建模式
45                 _stream = Bass.BASS_StreamCreateFile(file, 0L, 0L, BASSFlag.BASS_SAMPLE_FLOAT);
46 
47                 LoadEQ_(_stream);//应用EQ设置
48 
49                 Bass.BASS_ChannelPlay(_stream, true);//播放
50             }
51         }
52 
53 
54         private int[] _fxEQ = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
55         private float[] _fxCenter = { 31, 63, 125, 250, 500, 1000, 2000, 4000, 8000, 16000 };
56         private float[] _fxGain = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };//增益效果
57 
58         /// <summary>
59         /// 应用EQ设置
60         /// </summary>
61         /// <param name="_stream"></param>
62         private void LoadEQ_(int _stream)
63         {
64             BASS_DX8_PARAMEQ eq = new BASS_DX8_PARAMEQ();
65             for (int i = 0; i < _fxCenter.Length; i++)
66             {
67                 _fxEQ[i] = Bass.BASS_ChannelSetFX(_stream, BASSFXType.BASS_FX_DX8_PARAMEQ, 0);
68                 eq.fBandwidth = 18f;
69                 eq.fCenter = _fxCenter[i];
70                 eq.fGain = _fxGain[i];
71                 Bass.BASS_FXSetParameters(_fxEQ[i], eq);
72             }
73         }
74 
75         /// <summary>
76         /// 设置EQ
77         /// </summary>
78         /// <param name="band"></param>
79         /// <param name="gain"></param>
80         private void UpdateEQ(int band, float gain)
81         {
82             BASS_DX8_PARAMEQ eq = new BASS_DX8_PARAMEQ();
83             if (Bass.BASS_FXGetParameters(_fxEQ[band], eq))
84             {
85                 eq.fGain = _fxGain[band] = gain;
86                 Bass.BASS_FXSetParameters(_fxEQ[band], eq);
87             }
88         }
89 
90         private void trackBar_Scroll(object sender, EventArgs e)
91         {
92             TrackBar t = (TrackBar)sender;
93             int band = int.Parse(t.Tag.ToString());
94             UpdateEQ(band, t.Value);
95         }
96 
97         
98     }
99 }
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