C# 基于NAudio实现对Wav音频文件剪切(限PCM格式)

前言

c#基于naudio工具对wav音频文件进行剪切，将一个音频文件剪切成多个音频文件

注：调用方法前需要导入naudio.dll或者在nuget程序管理器搜索naudio并安装

本文是按时间剪切

实现代码

using naudio.wave;
using system;
using system.collections.generic;
using system.linq;
using system.text;
using system.threading.tasks;

namespace xxx.util
{
    public static class wavfileutils
    {
        /// <summary>
        /// 基于naudio工具对wav音频文件剪切（限pcm格式）
        /// </summary>
        /// <param name="inpath">目标文件</param>
        /// <param name="outpath">输出文件</param>
        /// <param name="cutfromstart">开始时间</param>
        /// <param name="cutfromend">结束时间</param>
        public static void trimwavfile(string inpath, string outpath, timespan cutfromstart, timespan cutfromend)
        {
            using (wavefilereader reader = new wavefilereader(inpath))
            {
                int filelength = (int)reader.length;using (wavefilewriter writer = new wavefilewriter(outpath, reader.waveformat))
                {
                    float bytespermillisecond = reader.waveformat.averagebytespersecond / 1000f;
                    int startpos = (int)math.round(cutfromstart.totalmilliseconds * bytespermillisecond);
                    startpos = startpos - startpos % reader.waveformat.blockalign;
                    int endpos = (int)math.round(cutfromend.totalmilliseconds * bytespermillisecond);
                    endpos = endpos - endpos % reader.waveformat.blockalign;
                    //判断结束位置是否越界
                    endpos = endpos > filelength ? filelength : endpos;
                    trimwavfile(reader, writer, startpos, endpos);
                }
            }
        }

        /// <summary>
        /// 重新合并wav文件
        /// </summary>
        /// <param name="reader">读取流</param>
        /// <param name="writer">写入流</param>
        /// <param name="startpos">开始流</param>
        /// <param name="endpos">结束流</param>
        private static void trimwavfile(wavefilereader reader, wavefilewriter writer, int startpos, int endpos)
        {
            reader.position = startpos;
            byte[] buffer = new byte[1024];
            while (reader.position < endpos)
            {
                int bytesrequired = (int)(endpos - reader.position);
                if (bytesrequired > 0)
                {
                    int bytestoread = math.min(bytesrequired, buffer.length);
                    int bytesread = reader.read(buffer, 0, bytestoread);
                    if (bytesread > 0)
                    {
                        writer.write(buffer, 0, bytesread);
                    }
                }
            }
        }
    }
}

调用：

string filepath = "d:\\wav\\test.wav";//需要切割的文件路径
int cuttimespan = 20;//切割的时间片段时间（秒）
fileinfo fi = new fileinfo(filepath);
//获取录音文件时长（秒）
int filetime = (int)util.cover(util.getvoicetime(filepath)) / 1000;
//计算文件需要切割多少等份
decimal filenum = math.ceiling((decimal)filetime / cuttimespan);
int i = 0;
while (i < filenum)
{
    string nowtime = util.gettimestamp();//当前时间戳
    //切割后保存的文件绝对地址
    var outputpath = system.io.path.combine(fi.directory.fullname, string.format("{0}_{1}{2}", fi.name.replace(fi.extension, ""), nowtime, fi.extension));
    //切割的开始时间
    timespan cutfromstart = timespan.fromseconds(i * cuttimespan);
    //切割的结束时间
    timespan cutfromend = cutfromstart + timespan.fromseconds(cuttimespan);
    //音频切割
    wavfileutils.trimwavfile(recordfile.filepath, outputpath, cutfromstart, cutfromend);
    i++;
}

util 类：

using shell32;
using system;
using system.diagnostics;
using system.io;
using system.net;
using system.net.sockets;
using system.text.regularexpressions;
using system.threading;
using system.windows.forms;

namespace xxx.util
{
    class util
    {
        /// <summary>
        /// 获取时间戳
        /// </summary>
        /// <returns></returns>
        public static string gettimestamp()
        {
            timespan ts = datetime.utcnow - new datetime(1970, 1, 1, 0, 0, 0, 0);
            return convert.toint64(ts.totalmilliseconds).tostring();
        }

        /// <summary>
        /// 返回音频时长
        /// </summary>
        /// <param name="songpath">音频文件路径</param>
        /// <returns></returns>
        public static string getvoicetime(string songpath)
        {
            string dirname = path.getdirectoryname(songpath);
            string songname = path.getfilename(songpath);
            shellclass sh = new shellclass();
            folder dir = sh.namespace(dirname);
            folderitem item = dir.parsename(songname);
            string songtime = regex.match(dir.getdetailsof(item, -1), "\\d:\\d{2}:\\d{2}").value;//返回音频时长
            return songtime;
        }

　　　   /// <summary>
        /// 时间格式转毫秒值
        /// </summary>
        /// <param name="time">时间字符串</param>
        /// <returns></returns>
        public static long cover(string time)
        {
            string[] a = time.split(':');
            if (long.parse(a[0]) == 0 && long.parse(a[1]) == 0)
            {
                return long.parse(a[2]) * 1000;
            }
            else if (long.parse(a[0]) == 0 && long.parse(a[1]) != 0)
            {
                return (long.parse(a[1]) * 60 + long.parse(a[2])) * 1000;
            }
            else if (long.parse(a[0]) != 0 && long.parse(a[1]) == 0)
            {
                return ((long.parse(a[0]) * 60 * 60) + long.parse(a[2])) * 1000;
            }
            else if (long.parse(a[0]) != 0 && long.parse(a[1]) != 0)
            {
                return (((long.parse(a[0]) * 60) + long.parse(a[1])) * 60) * 1000;
            }
            return 0;
        }
    }
}

效果图

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