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：

using System;
using System.Windows.Forms;
using Un4seen.Bass;

namespace WindowsFormsApp4
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        string file = "";
        int _stream = 0;
        private void Form1_Load(object sender, EventArgs e)
        {
            bool r = Bass.BASS_Init(-1, 48000, BASSInit.BASS_DEVICE_CPSPEAKERS, this.Handle);

            if (!r)
            {
                MessageBox.Show("出错了，" + Bass.BASS_ErrorGetCode().ToString());
                return;
            }
        }

        /// <summary>
        /// 打开文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog o = new OpenFileDialog();
            if (o.ShowDialog() == DialogResult.OK)
            {
                file = o.FileName;

                if (_stream != 0)
                    Bass.BASS_ChannelStop(_stream);

                //第一个参数是文件名，
                //第二个参数是文件流开始位置，
                //第三个是文件流长度 0为使用文件整个长度，
                //最后一个是流的创建模式
                _stream = Bass.BASS_StreamCreateFile(file, 0L, 0L, BASSFlag.BASS_SAMPLE_FLOAT);

                LoadEQ_(_stream);//应用EQ设置

                Bass.BASS_ChannelPlay(_stream, true);//播放
            }
        }


        private int[] _fxEQ = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        private float[] _fxCenter = { 31, 63, 125, 250, 500, 1000, 2000, 4000, 8000, 16000 };
        private float[] _fxGain = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };//增益效果

        /// <summary>
        /// 应用EQ设置
        /// </summary>
        /// <param name="_stream"></param>
        private void LoadEQ_(int _stream)
        {
            BASS_DX8_PARAMEQ eq = new BASS_DX8_PARAMEQ();
            for (int i = 0; i < _fxCenter.Length; i++)
            {
                _fxEQ[i] = Bass.BASS_ChannelSetFX(_stream, BASSFXType.BASS_FX_DX8_PARAMEQ, 0);
                eq.fBandwidth = 18f;
                eq.fCenter = _fxCenter[i];
                eq.fGain = _fxGain[i];
                Bass.BASS_FXSetParameters(_fxEQ[i], eq);
            }
        }

        /// <summary>
        /// 设置EQ
        /// </summary>
        /// <param name="band"></param>
        /// <param name="gain"></param>
        private void UpdateEQ(int band, float gain)
        {
            BASS_DX8_PARAMEQ eq = new BASS_DX8_PARAMEQ();
            if (Bass.BASS_FXGetParameters(_fxEQ[band], eq))
            {
                eq.fGain = _fxGain[band] = gain;
                Bass.BASS_FXSetParameters(_fxEQ[band], eq);
            }
        }

        private void trackBar_Scroll(object sender, EventArgs e)
        {
            TrackBar t = (TrackBar)sender;
            int band = int.Parse(t.Tag.ToString());
            UpdateEQ(band, t.Value);
        }

        
    }
}