ffmpeg 转成MP3采样率8000

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.IO;
using System.Threading;

namespace Win
{
    public partial class Form1 : Form
    {
        public static string url="";
        public Form1()
        {
            InitializeComponent();
        }
        static FileSystemWatcher watcher = new FileSystemWatcher();
        /// <summary>       
        /// 初始化监听       
        /// </summary>       
        /// <param name="StrWarcherPath">需要监听的目录</param>       
        /// <param name="FilterType">需要监听的文件类型(筛选器字符串)</param>       
        /// <param name="IsEnableRaising">是否启用监听</param>       
        /// <param name="IsInclude">是否监听子目录</param>        
        private static void WatcherStrat(string StrWarcherPath, string FilterType, bool IsEnableRaising, bool IsInclude)
        {
            //初始化监听           
            watcher.BeginInit();
            //设置监听文件类型           
            watcher.Filter = FilterType;
            //设置是否监听子目录           
            watcher.IncludeSubdirectories = IsInclude;
            //设置是否启用监听?           
            watcher.EnableRaisingEvents = IsEnableRaising;
            //设置需要监听的更改类型(如:文件或者文件夹的属性,文件或者文件夹的创建时间;NotifyFilters枚举的内容)          
            watcher.NotifyFilter = NotifyFilters.Attributes | NotifyFilters.CreationTime | NotifyFilters.DirectoryName | NotifyFilters.FileName | NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.Security | NotifyFilters.Size;
            //设置监听的路径           
            watcher.Path = StrWarcherPath;
            //注册创建文件或目录时的监听事件           
            watcher.Created += new FileSystemEventHandler(watch_created);
            //注册当指定目录的文件或者目录发生改变的时候的监听事件  
            watcher.Changed += new FileSystemEventHandler(watch_changed);
            //注册当删除目录的文件或者目录的时候的监听事件           
            watcher.Deleted += new FileSystemEventHandler(watch_deleted);
            //当指定目录的文件或者目录发生重命名的时候的监听事件           
            watcher.Renamed += new RenamedEventHandler(watch_renamed);
            //结束初始化           
            watcher.EndInit();
        }

        /// <summary>       
        /// 创建文件或者目录时的监听事件      
        /// </summary>      
        /// <param name="sender"></param>       
        /// <param name="e"></param>       
        private static void watch_created(object sender, FileSystemEventArgs e)
        {
            //事件内容
            string fileName = e.FullPath;
            string targetFileName = "";
            WavConvertAmr.ConvertToMP3 toamr = new WavConvertAmr.ConvertToMP3();
            try
            {
                if (!System.IO.Path.GetExtension(fileName).Equals(".mp3", StringComparison.CurrentCultureIgnoreCase))
                {
                    targetFileName = e.FullPath.Substring(0, e.FullPath.LastIndexOf(".")) + ".mp3";
                    toamr.ConvertToAmr(System.Windows.Forms.Application.StartupPath, fileName, targetFileName);
                }
                //转换采样率
                targetFileName = e.FullPath.Substring(0, e.FullPath.LastIndexOf(".")) + ".wav";
                toamr.ConvertToAmr(System.Windows.Forms.Application.StartupPath, fileName, targetFileName);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        /// <summary>       
        /// 当指定目录的文件或者目录发生改变的时候的监听事件      
        /// </summary>       
        /// <param name="sender"></param>       
        /// <param name="e"></param>       
        private static void watch_changed(object sender, FileSystemEventArgs e)
        {
            //事件内容    
            //MessageBox.Show("发生改变");
        }
        /// <summary>       
        /// 当删除目录的文件或者目录的时候的监听事件       
        /// </summary>       
        /// <param name="sender"></param>             
        /// <param name="e"></param>      
        private static void watch_deleted(object sender, FileSystemEventArgs e)
        {
            //事件内容
        }
        /// <summary>       
        /// 当指定目录的文件或者目录发生重命名的时候的事件      
        /// </summary>      
        /// <param name="sender"></param>       
        /// <param name="e"></param>       
        private static void watch_renamed(object sender, RenamedEventArgs e)
        {
            //事件内容      
        }
        /// <summary>       
        /// 启动或者停止监听       
        /// </summary>       
        /// <param name="IsEnableRaising">True:启用监听,False:关闭监听</param>       
        private void WatchStartOrSopt(bool IsEnableRaising)
        {
            watcher.EnableRaisingEvents = IsEnableRaising;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Record re = new Record();
            re.Show();
        }
        private void button1_Click_1(object sender, EventArgs e)
        {
            //url = System.AppDomain.CurrentDomain.BaseDirectory.Replace("WavConvertAmr\Win\bin\Debug\", "") + textBox1.Text;
            try
            {
                url = System.AppDomain.CurrentDomain.BaseDirectory.Replace("Debug\", "") + textBox1.Text;
                WatcherStrat(url, "*", true, false);
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            this.panel1.Visible = true;
            MessageBox.Show("启动成功！");
        }

        private void button2_Click_1(object sender, EventArgs e)
        {
            OpenFileDialog open = new OpenFileDialog();
            if (open.ShowDialog() == DialogResult.OK)
            {
                string fileName = open.FileName;
                string targetFileName = open.FileName.Substring(0, open.FileName.LastIndexOf(".")) + ".wav";
                WavConvertAmr.ConvertToMP3 toamr = new WavConvertAmr.ConvertToMP3();
                toamr.ConvertToAmr(System.Windows.Forms.Application.StartupPath, fileName, targetFileName);
                MessageBox.Show("转换成功");

            }
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace WavConvertAmr
{
    public class ConvertToMP3
    {
        
        /// <summary>
        /// 将Wav音频转成Amr手机音频
        /// </summary>
        /// <param name="applicationPath">ffmeg.exe文件路径</param>
        /// <param name="fileName">WAV文件的路径(带文件名)</param>
        /// <param name="targetFilName">生成目前amr文件路径（带文件名）</param>
        public void ConvertToAmr(string applicationPath, string fileName, string targetFilName)
        {
            //string c = applicationPath + @"ffmpeg.exe -y -i " + fileName + " -ar 8000 -ab 128 -ac 1 " + targetFilName;
            string c = """ + applicationPath + @"ffmpeg.exe" + """ + " -i  " + """ + fileName + """ + " -ar 8000  -y  " + """ + targetFilName + """;
            Cmd(c);
        }

        /// <summary>
        /// 执行Cmd命令
        /// </summary>
        private void Cmd(string c)
        {
            try
            {
                System.Diagnostics.Process process = new System.Diagnostics.Process();
                process.StartInfo.FileName = "cmd.exe";
                process.StartInfo.UseShellExecute = false;
                process.StartInfo.CreateNoWindow = true;
                process.StartInfo.RedirectStandardOutput = true;
                process.StartInfo.RedirectStandardInput = true;
                process.Start();

                process.StandardInput.WriteLine(c);
                process.StandardInput.AutoFlush = true;
                process.StandardInput.WriteLine("exit");
                StreamReader reader = process.StandardOutput;//截取输出流
                //process.WaitForExit();
            }
            catch
            { }
        }
    }     
}