Wav 到 C# 中的位图转换

Question

我正在尝试编写一个程序来读取 .wav 文件，将其转换为位图，然后将位图转换回 wav 文件。我已经在 python 中使用 Wave 模块做到了这一点，并且能够通过这种方式创建一些声音上有趣的衰减。

我的代码运行了，但没有得到预期的结果，只有白噪音。

Wav转位图

 private void button1_Click(object sender, EventArgs e)
    {
        System.IO.Stream load_wav = new System.IO.MemoryStream();
        openFileDialog1.Filter = "WAV|*.wav";
        openFileDialog1.ShowDialog();
        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            try
            {
                if ((load_wav = openFileDialog1.OpenFile()) != null)
                {
                    using (load_wav)
                    {
                        using (WaveFileReader reader = new WaveFileReader(load_wav))
                        {

                            int BitsPerSample;
                            int SampleRate;
                            BitsPerSample = reader.WaveFormat.BitsPerSample;
                            SampleRate = reader.WaveFormat.SampleRate;
                            string config = SampleRate.ToString();
                            // Write sample config to .ini
                            System.IO.StreamWriter file = new System.IO.StreamWriter(".\config.ini");
                            file.WriteLine(config);
                            file.Close();
                            if (BitsPerSample == 16) // Check 16bit
                            {
                                // Read WAV
                                byte[] in_buffer = new byte[reader.Length];
                                int read = reader.Read(in_buffer, 0, in_buffer.Length);
                                MessageBox.Show("Load OK");

                                // Convert byte array to stream 
                                Bitmap output = new Bitmap(600, 600); 
                                Rectangle rect = new Rectangle(0, 0, output.Width, output.Height);
                                BitmapData bmpData = output.LockBits(rect, ImageLockMode.ReadWrite, output.PixelFormat);
                                IntPtr ptr = bmpData.Scan0;
                                System.Runtime.InteropServices.Marshal.Copy(in_buffer, 0, ptr, in_buffer.Length);
                                output.UnlockBits(bmpData);
                                pictureBox1.Image = output;
                                output.Save(".\output.bmp");



                            }

                            else
                            {
                                MessageBox.Show("16 bit WAV files only :-(");
                            }

位图转 Wav

 private void button2_Click(object sender, EventArgs e)
    {

        if ((pictureBox1.Image == null))
        {

        }
        else
        {
            // Read sample .ini
            System.IO.StreamReader file = new System.IO.StreamReader(".\config.ini");
            string config = file.ReadLine();
            file.Close();
            int SampleRate = Convert.ToInt32(config);
            // Convert bmp to byte array
            Bitmap output = Image.FromFile(".\output.bmp") as Bitmap;
            ImageConverter converter = new ImageConverter();
            byte[] out_bytes = (byte[])converter.ConvertTo(output, typeof(byte[]));
            // Convert byte array to stream
            System.IO.MemoryStream out_stream = new System.IO.MemoryStream(out_bytes);
            // Append valid WAV header to stream
            WaveFormat waveformat = new WaveFormat(SampleRate, 16, 2);
            var reader = new RawSourceWaveStream(out_stream, waveformat);
            using (var convertedStream = WaveFormatConversionStream.CreatePcmStream(reader))
            {
            // Save dialog
                SaveFileDialog savefiledialog1 = new SaveFileDialog();
                savefiledialog1.Title = "export wav";
                savefiledialog1.Filter = "wav|*.wav";
                savefiledialog1.ShowDialog();
                if (savefiledialog1.FileName != "")
                    {
                        WaveFileWriter.CreateWaveFile(savefiledialog1.FileName, convertedStream);
                    }
            }
            out_stream.Close();


        }
    }

我认为问题在于我将字节数组转换为流的方式。

Answer 1

查看我的 python 代码的 bmp 输出，生成的位图是 24 位的。我的 C# 代码生成的位图是 32 位的。

使用 EncoderParameters 解决

// Setup 24 bit bmp encoder
System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.ColorDepth; 
myEncoder = System.Drawing.Imaging.Encoder.ColorDepth;
EncoderParameters myEncoderParameters = new EncoderParameters(1);
EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, 24L);
myEncoderParameters.Param[0] = myEncoderParameter;
var codec = GetEncoderInfo("image/bmp");

根据需要，音频输出现在是音频输入的降级版本。

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