在.NET Assembly mscorlib System.IO命名空间中,我使用ReadInt16()方法循环音频数据字节并将有符号整数值转储到文本文件中。如何解释与一个采样率相关的两个值?也就是说,如果我有一秒钟的单声道数据将有88200字节,因此使用ReadInt16()返回88200个离散整数。这是太多的信息,我应该只有44100个整数。所以我需要使用不同的方法,或者每次迭代可以将循环推进1。
非常感谢..........米奇
答案 0 :(得分:0)
通常,当您读取数据数组时,您的代码应如下所示:
for(int i = 0; i < totalNumberOfEntries; i++)
{
// read all data for this entry
var component1 = reader.ReadXXX();
var component2 = reader.ReadXXX();
// deal with data for this entry
someEntryStroage.Add(new Entry(component1, component2);
}
在您的情况下,您很可能(我不知道Wave文件格式)您需要读取Int16值对(如果样本在一起),或者如果一个通道的数据在另一个通道之后,则分别读取通道。
答案 1 :(得分:0)
你必须阅读chunkinfos。数据块告诉您必须读取多少字节。 WaveFormat告诉你很多Averagebytespersecond你有,等等。我有一些VB代码......
答案 2 :(得分:0)
将带有sharpdevelop的VB代码转换为C#也许它有点帮助...
using System;
using System.IO;
public class ChunkInfo
{
private byte[] m_Header;
private long m_Length;
private long m_OffSet;
public ChunkInfo(string Header)
{
m_Header = new byte[Header.Length];
for (int i = 0; i <= m_Header.GetUpperBound(0); i++)
{
m_Header[i] = (byte)Header[i];
}
}
public ChunkInfo(byte[] Header)
{
m_Header = Header;
}
public void Read(BinaryReader br)
{
m_OffSet = SearchOffset(br);
if (m_OffSet >= 0)
{
br.BaseStream.Position = m_OffSet + m_Header.Length;
m_Length = br.ReadInt32();
}
}
public void Write(BinaryWriter bw)
{
bw.Write(m_Header);
bw.Write(m_Length);
}
public long Length
{
get { return m_Length; }
}
public long OffSet
{
get { return m_OffSet; }
}
private long SearchOffset(BinaryReader br)
{
byte[] haystack = null;
bool found = false;
long offset = 0;
long basepos = 0;
int hlength = 260;
long basepos_grow = hlength - m_Header.Length;
while (!(found || (basepos >= br.BaseStream.Length)))
{
br.BaseStream.Position = basepos;
haystack = br.ReadBytes(hlength);
offset = BoyerMooreHorspool.find(haystack, m_Header);
found = offset >= 0;
if (found)
{
offset += basepos;
break;
}
else
{
basepos += basepos_grow;
}
}
return offset;
}
}
public static class BoyerMooreHorspool
{
//detects a needle in the haystack
const int UBYTE_MAX = 255;
static int[] bad_char_skip4 = new int[UBYTE_MAX + 3];
static int[] bad_char_skip8 = new int[UBYTE_MAX + 3];
static bool IsInitialized = false;
public static void init()
{
//little optimization for needles with length 4 or 8
for (int i = 0; i <= UBYTE_MAX + 2; i++)
{
bad_char_skip4[i] = 4;
bad_char_skip8[i] = 8;
}
IsInitialized = true;
}
public static int find(byte[] haystack, byte[] needle, int start = 0)
{
if (!IsInitialized) init();
int i_n = 0;
//needle index
int n_n = needle.Length;
int[] bad_char_skip = null;
switch (n_n)
{
case 4:
bad_char_skip = bad_char_skip4;
break;
case 8:
bad_char_skip = bad_char_skip8;
break;
default:
bad_char_skip = new int[UBYTE_MAX + 3];
for (i_n = 0; i_n <= UBYTE_MAX + 2; i_n++)
{
bad_char_skip[i_n] = n_n;
}
break;
}
int ifind = -1;
//if not found then return - 1
int i_h = start;
//haystack index
int n_h = haystack.Length;
if (n_n > n_h)
throw new ArgumentOutOfRangeException("needle", "needle is to long");
int last = n_n - 1;
for (i_n = 0; i_n <= last - 1; i_n++)
{
bad_char_skip[needle[i_n]] = last - i_n;
}
byte bcs = 0;
int bhs = 0;
while ((n_h - start) >= n_n)
{
i_n = last;
while (haystack[i_h + i_n] == needle[i_n])
{
i_n -= 1;
if (i_n == 0)
{
ifind = i_h;
break;
}
}
bhs = haystack[i_h + last];
bcs = (byte)(bad_char_skip[bhs]);
n_h -= bcs;
i_h += bcs;
}
return ifind;
}
}
答案 3 :(得分:0)
using System;
using System.IO;
public struct WaveFormat
{
private short m_FormatTag; // most often PCM = 1
private short m_nChannels; // number of channels
private int m_SamplesPerSecond; // samples per second eg 44100
private int m_AvgBytesPerSecond; // bytes per second eg 176000
private short m_BlockAlign; // blockalign (byte per sample) eg 4 bytes
private short m_BitsPerSample; // bits per sample, 8, 16, 24
public WaveFormat(byte BPS, int SPS, byte nChn)
{
m_FormatTag = 1; //PCM
m_nChannels = nChn;
m_SamplesPerSecond = SPS;
m_BitsPerSample = BPS;
m_BlockAlign = (short)(m_nChannels * m_BitsPerSample / 8);
m_AvgBytesPerSecond = (int)(m_BlockAlign * m_SamplesPerSecond);
}
public short FormatTag
{
get { return m_FormatTag; }
set { m_FormatTag = value; }
}
public short Channels
{
get { return m_nChannels; }
}
public int SamplesPerSecond
{
get { return m_SamplesPerSecond; }
}
public int AvgBytesPerSecond
{
get { return m_AvgBytesPerSecond; }
}
public short BlockAlign
{
get { return m_BlockAlign; }
}
public short BitsPerSample
{
get { return m_BitsPerSample; }
}
public void Read(BinaryReader br)
{
m_FormatTag = br.ReadInt16();
m_nChannels = br.ReadInt16();
m_SamplesPerSecond = br.ReadInt32();
m_AvgBytesPerSecond = br.ReadInt32();
m_BlockAlign = br.ReadInt16();
m_BitsPerSample = br.ReadInt16();
}
public void Write(BinaryWriter bw)
{
bw.Write(m_FormatTag);
bw.Write(m_nChannels);
bw.Write(m_SamplesPerSecond);
bw.Write(m_AvgBytesPerSecond);
bw.Write(m_BlockAlign);
bw.Write(m_BitsPerSample);
}
public override string ToString()
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
sb.AppendLine("FormatTag: " + m_FormatTag.ToString());
sb.AppendLine("nChannels: " + m_nChannels.ToString());
sb.AppendLine("SamplesPerSecond: " + m_SamplesPerSecond.ToString());
sb.AppendLine("AvgBytesPerSecond: " + m_AvgBytesPerSecond.ToString());
sb.AppendLine("BlockAlign: " + m_BlockAlign.ToString());
sb.AppendLine("BitsPerSample: " + m_BitsPerSample.ToString());
return sb.ToString();
}
}