/// <summary>
/// Provides setting of the mp3 frame header used to convert between time per frame and frame number.
/// </summary>
/// <param name="header">MP3AudioFrameHeader used to calculate the time each MP3AudioFrame contains.</param>
public void SetFrameLength(MP3AudioFrameHeader header)
{
if (header == null)
{
throw new ArgumentNullException("Header");
}
ticksPerFrame = header.SampleCount * TimeSpan.TicksPerSecond / header.SamplingRate;
}
/// <summary>
/// 获取数据帧长度
/// </summary>
/// <returns></returns>
private int GetAuidoFrameLength(out double playTime)
{
playTime = 0;
byte[] headerBuffer = MP3Buffer.GetRange(0, 4).ToArray();
//MP3Stream.Read(headerBuffer, 0, headerBuffer.Length);
////读取位置回到ff fb
//MP3Stream.Position = MP3Stream.Position - 4;
if (headerBuffer[0] != 0xFF)
{
Console.WriteLine("没有读取到FF头");
return(0);
}
MP3AudioFrameHeader header = new MP3AudioFrameHeader(headerBuffer);
int length = 0;
//每帧采样数
int frameCount = FrameCountDictionary[header.Version][header.Layer];
//比特率
int kbps = KBPSDictionary[header.Version][header.Layer][header.BitrateIndex];
//采样率
double khz = KHZDictionary[header.Version][header.SamplingFrequency];
switch (header.Layer)
{
//11 -> Layer 1, L1
case "11":
break;
//10 -> Layer 2, L2
//01 -> Layer 3, L3
case "10":
case "01":
length = (int)Math.Floor(((frameCount / 8 * kbps) / khz)) + (header.Padding == "0" ? 0 : 1);
playTime = frameCount / khz;
break;
default:
break;
}
return(length);
}
