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我試圖從基於此答案WAV文件繪製的波形: https://stackoverflow.com/a/1215472/356635企圖拉攏波的形式,但沒有得出任何數據
不幸的是,它會產生一個大黑方每次。我正在努力研究這是爲什麼,有人能夠發現問題嗎? normalisedData
中的所有值都介於-1 and +1
之間。 test.wav
文件是播放5秒鐘警報聲音的Windows wav文件。
這裏是我的代碼:
using System;
using System.Drawing;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
const string rootDir = "C:\\inetpub\\wwwroot\\";
if (File.Exists(rootDir + "test.png"))
{
File.Delete(rootDir + "test.png");
}
var stream = new MemoryStream(File.ReadAllBytes(rootDir + "test.wav"));
var data = stream.ToArray();
stream.Dispose();
var normalisedData = FloatArrayFromByteArray(data);
// Get max value in data
var maxValue = 0f;
for (var i = 0; i < normalisedData.Length; i++)
{
if (normalisedData[i] > maxValue) maxValue = normalisedData[i];
}
// Normalise data
for (var i = 0; i < normalisedData.Length; i++)
{
normalisedData[i] = (data[i]/maxValue) * 100f;
}
// Save picture
var picture = DrawNormalizedAudio(normalisedData, Color.LimeGreen);
picture.Save(rootDir + "test.png", System.Drawing.Imaging.ImageFormat.Png);
picture.Dispose();
}
public static Bitmap DrawNormalizedAudio(float[] data, Color color)
{
Bitmap bmp;
bmp = new Bitmap(500,500);
int BORDER_WIDTH = 5;
int width = bmp.Width - (2 * BORDER_WIDTH);
int height = bmp.Height - (2 * BORDER_WIDTH);
using (Graphics g = Graphics.FromImage(bmp))
{
g.Clear(Color.Black);
Pen pen = new Pen(color);
int size = data.Length;
for (int iPixel = 0; iPixel < width; iPixel++)
{
// determine start and end points within WAV
int start = (int)((float)iPixel * ((float)size/(float)width));
int end = (int)((float)(iPixel + 1) * ((float)size/(float)width));
float min = float.MaxValue;
float max = float.MinValue;
for (int i = start; i < end; i++)
{
float val = data[i];
min = val < min ? val : min;
max = val > max ? val : max;
}
int yMax = BORDER_WIDTH + height - (int)((max + 1) * .5 * height);
int yMin = BORDER_WIDTH + height - (int)((min + 1) * .5 * height);
g.DrawLine(pen, iPixel + BORDER_WIDTH, yMax,
iPixel + BORDER_WIDTH, yMin);
}
}
return bmp;
}
public float[] FloatArrayFromByteArray(byte[] input)
{
float[] output = new float[input.Length/4];
System.Buffer.BlockCopy(input, 0, output, 0, input.Length);
return output;
}
}
如果不考慮文件頭,等等? –
啊,可以解釋它! –