/// <summary> /// 文件裁剪截取 /// </summary> 健康知识平台重庆保胆取石 重庆胆结石医院 public class WavScissorHelper { public static bool GetWavFileScissor(string OriginalAudioFilePath, string DestinedAudioFilePath, int beginCutTime, int endCutTime, ref string errorInfo) { if (!File.Exists(OriginalAudioFilePath)) { errorInfo = string.Format("源文件:[{0}]不存在!", OriginalAudioFilePath); return false; } if (!Directory.Exists(Path.GetDirectoryName(DestinedAudioFilePath))) { errorInfo = string.Format("文件夹:[{0}]不存在!", Path.GetDirectoryName(DestinedAudioFilePath)); return false; } if ((beginCutTime < 0) || (endCutTime < 0) || (beginCutTime > endCutTime)) { errorInfo = string.Format("截取时间[{0}][{1}]有误!", beginCutTime, endCutTime); return false; } try { WavFile oldFile = new WavFile(OriginalAudioFilePath); if (endCutTime > oldFile.PlayTime) { errorInfo = string.Format("结束截取时间[{0}]大于音频文件播放时间[{1}]!", endCutTime, oldFile.PlayTime); return false; } int timeSpan = endCutTime - beginCutTime; WavFile newFile = new WavFile(DestinedAudioFilePath); newFile.WavFormat = oldFile.WavFormat; byte[] newAudioBytes = new byte[oldFile.WavFormat.ByteRate * timeSpan]; Array.Copy(oldFile.AudioDataBytes, oldFile.WavFormat.ByteRate * beginCutTime, newAudioBytes, 0, newAudioBytes.Length); newFile.WriteWavFile(newAudioBytes); return true; } catch (Exception e) { return false; } } } /// <summary> /// 淡入淡出处理 /// </summary> public class WavFadeHelper { private WavFile _wavFile; public WavFadeHelper(string wavFilePath) { _wavFile = new WavFile(wavFilePath); } public bool FadeAtFirstSec(FadeMode fadeMode, long fadeLength) { return FadeAtSec(fadeMode, 0, fadeLength); } public bool FadeAtEndSec(FadeMode fadeMode, long fadeLength) { long totalTime = _wavFile.PlayTime; if (totalTime < fadeLength) fadeLength = totalTime; long startTime = totalTime - fadeLength; return FadeAtSec(fadeMode, startTime, startTime + fadeLength); } public bool FadeAtSec(FadeMode fadeMode, long startSec, long endSec) { //总播放时间 long totalTime = _wavFile.PlayTime; //采样位数 // 16 bit 纵坐标为采样系数 细化为 2^16= 65535份 16位二进制表示 [ 0000 0000 0000 0000 ] // 即为2Byte (每单位时间内产生 2Byte 的音频数据) int byteNumPerSample = _wavFile.WavFormat.BitsPerSample / 8; //采样频率 // 11025Hz 横坐标为采样频率 单位时间为: 1/11025 s //单位时间内产生的的音频数据大小为 2Byte * 11025Hz * 声道数 //audioData 是按字节处理 16bit采样 每次获取两个字节进行处理 //开始位置 存储单元索引 long startIndex = startSec * byteNumPerSample * _wavFile.WavFormat.SampleRate; if (startIndex % byteNumPerSample > 0) startIndex -= startIndex % byteNumPerSample; //结束位置 存储单元索引 long endIndex = endSec * byteNumPerSample * _wavFile.WavFormat.SampleRate; if (endIndex > _wavFile.AudioDataBytes.Length - 1) endIndex = _wavFile.AudioDataBytes.Length - 1; //字节数组 音频数据 byte[] audioDatas = _wavFile.AudioDataBytes; //初始衰减率 double rate = 1.0; //对每个单位时间内的 样点幅值 进行衰减 //从淡化开始时间到结束时间共有 [ 采样频率 * 时间段(s) * 采样位数/8(Byte) ] 个存储单元 //每次取出 采样位数/8(Byte) 个存储单元进行衰减 // i 的值为每次衰减处理时的 字节读取位置 (索引) for (int i = (int)startIndex; i < endIndex; i += byteNumPerSample) { //衰减率的方向与淡入淡出有关 //衰减率的大小与当前读取处理字节的索引位置有关 if (fadeMode == FadeMode.FadeOut) rate = (double)(endIndex - i) / (endIndex - startIndex); else rate = (double)(i - startIndex) / (endIndex - startIndex); //单位时间内的字节数为1 即采用8bit采样位数 每次只需要对一个字节进行衰减 if (byteNumPerSample == 1) { //获取需要衰减的字节值 byte audioData = audioDatas[i]; //进行衰减线性处理 byte changedAudioData = (byte)((double)audioData * rate); //byte changedAudioData = Convert.ToByte((double)audioData * rate); //对原来的值进行更改 audioDatas[i] = changedAudioData; } else if (byteNumPerSample == 2) { //16bit 量化 每单位时间产生2Byte数据 因此取 2Byte 的数据进行衰减处理 byte[] audioData = new byte[2]; Array.Copy(audioDatas, i, audioData, 0, 2); //单个样点幅值 double sample = 0; //转换为整数进行线性处理 sample = (double)BitConverter.ToInt16(audioData, 0) * rate; //转换为字节存储 byte[] buffer = BitConverter.GetBytes(Convert.ToInt16(sample)); if (!BitConverter.IsLittleEndian) Array.Reverse(buffer); Array.Copy(buffer, 0, audioDatas, i, 2); } } _wavFile.WriteWavFile(audioDatas); return true; } } /// <summary> /// 淡入淡出模式 /// </summary> public enum FadeMode { FadeIn, FadeOut } /// <summary> /// WAV 文件 /// </summary> public class WavFile { private WavFormat _wavFormat; //文件格式 private long _fileLength; //文件长度 private string _filePath; //文件路径 private byte[] _audioData; //语音数据 private WavFile() { } public WavFile(string filePath) { _filePath = filePath; } /// <summary> /// 文件格式 /// </summary> public WavFormat WavFormat { get { if (_wavFormat == null) _wavFormat = GetWavFormat(); return _wavFormat; } set { _wavFormat = value; } } /// <summary> /// 文件大小 /// </summary> public long FileLength { get { if (_wavFormat == null) _wavFormat = GetWavFormat(); return _fileLength; } set { _fileLength = value; } } /// <summary> /// 播放时长 /// </summary> public long PlayTime { get { if (_wavFormat == null) _wavFormat = GetWavFormat(); return _audioData.Length / _wavFormat.ByteRate; } } /// <summary> /// 语音数据 /// </summary> public byte[] AudioDataBytes { get { if (_wavFormat == null) _wavFormat = GetWavFormat(); return _audioData; } set { _audioData = value; } } /// <summary> /// 设置Wav文件格式 /// </summary> /// <param name="bitsPerSample">采样位数</param> /// <param name="channels">声道数</param> /// <param name="sampleRate">采样率</param> public void SetWavFormat(int bitsPerSample, int channels, int sampleRate) { _wavFormat = new WavFormat(); _wavFormat.BitsPerSample = bitsPerSample; _wavFormat.Channels = channels; _wavFormat.SampleRate = sampleRate; } /// <summary> /// 写文件 /// </summary> /// <param name="audioData">音频数据</param> public void WriteWavFile(byte[] audioData) { WriteWavFile(_wavFormat, audioData, 0, audioData.Length); } /// <summary> /// 写文件 /// </summary> /// <param name="wavFormat">文件格式</param> /// <param name="audioData">音频数据</param> /// <param name="startIndex">audioData数组开始索引位置</param> /// <param name="length">写入audioData数组长度</param> public void WriteWavFile(WavFormat wavFormat, byte[] audioData, int startIndex, int length) { FileStream fs = null; BinaryWriter bw = null; try { fs = new FileStream(_filePath, FileMode.Create, FileAccess.Write); bw = new BinaryWriter(fs); fs.Position = 0; bw.Write(new char[4] { 'R', 'I', 'F', 'F' }); //ChunkFileSize bw.Write((int)(length + 44 - 8)); bw.Write(new char[8] { 'W', 'A', 'V', 'E', 'f', 'm', 't', ' ' }); bw.Write((int)16); bw.Write((short)1); bw.Write((short)wavFormat.Channels); bw.Write(wavFormat.SampleRate); bw.Write((int)(wavFormat.SampleRate * ((wavFormat.BitsPerSample * wavFormat.Channels) / 8))); bw.Write((short)((wavFormat.BitsPerSample * wavFormat.Channels) / 8)); bw.Write((short)wavFormat.BitsPerSample); bw.Write(new char[4] { 'd', 'a', 't', 'a' }); bw.Write(length); bw.Write(audioData, startIndex, length); } finally { if (bw != null) bw.Close(); if (fs != null) { fs.Close(); fs.Dispose(); } } } /// <summary> /// 获取Wav文件格式 /// </summary> /// <returns></returns> private WavFormat GetWavFormat() { FileStream fs = null; BinaryReader br = null; WavFormat wavFormat = new WavFormat(); try { fs = new FileStream(_filePath, FileMode.Open, FileAccess.Read); br = new BinaryReader(fs); _fileLength = fs.Length; fs.Position = 22; wavFormat.Channels = br.ReadInt16(); fs.Position = 24; wavFormat.SampleRate = br.ReadInt32(); fs.Position = 28; wavFormat.ByteRate = br.ReadInt32(); fs.Position = 34; wavFormat.BitsPerSample = br.ReadInt16(); //The audio data fs.Position = 44; int dataByteSize = (int)(fs.Length - 44); if (_audioData == null) _audioData = new byte[dataByteSize]; fs.Read(_audioData, 0, dataByteSize); } finally { if (br != null) br.Close(); if (fs != null) { fs.Close(); fs.Dispose(); } } return wavFormat; } } /// <summary> /// WAV 文件格式 /// </summary> public class WavFormat { /// <summary> /// 采样位数 /// </summary> public int BitsPerSample; /// <summary> /// 声道数 /// </summary> public int Channels; /// <summary> /// 采样率 /// </summary> public int SampleRate; /// <summary> /// 传输速率(播放速率) /// </summary> public long ByteRate; }