private int getBitrate()
{
// If the file has a variable bitrate, then we return an integer average bitrate,
// otherwise, we use a lookup table to return the bitrate
if (IsVBR())
{
//double medFrameSize = (double)lngFileSize / (double)getNumberOfFrames();
double medFrameSize = (double)getAudioFileSize() / (double)getNumberOfFrames();
return((int)((medFrameSize * (double)firstFrame.getFrequency()) / (1000.0 * ((firstFrame.LayerIndex == 3) ? 12.0 : 144.0))));
}
else
{
return(firstFrame.getBitrate());
}
}
public MP3(string FileName)
{
Console.WriteLine(FileName);
FileStream fs = new FileStream(FileName, FileMode.Open, FileAccess.Read);
Valid = false;
// Set the filename not including the path information
strFileName = @fs.Name;
char[] chrSeparators = new char[] { '\\', '/' };
string[] strSeparator = strFileName.Split(chrSeparators);
int intUpper = strSeparator.GetUpperBound(0);
strFileName = strSeparator[intUpper];
// Replace ' with '' for the SQL INSERT statement
strFileName = strFileName.Replace("'", "''");
// Set the file size
lngFileSize = fs.Length;
byte[] bytHeader = new byte[4];
byte[] bytVBitRate = new byte[12];
int intPos = 0;
// Keep reading 4 bytes from the header until we know for sure that in
// fact it's an MP3
int nextFrame = 0; //Jeff - Location in stream to next Frame (current position + framesize)
//Read if id3v1 exists
id3v1 = new ID3v1Tag(fs);
//Read if id3v2 exists
id3v2 = new ID3v2Tag(fs);
//Read if lyrics3 exists
lyrics3 = new Lyrics3Tag(fs, id3v1.Exists);
//Read if APEv2 exists
apev2 = new APEv2Tag(fs, id3v1, lyrics3, true);
//Pass up the ID3v2 tag (if it exists)
if (id3v2.Exists)
{
if (!id3v2.FooterExists)
{
intPos = (int)id3v2.TagSize + 10; //+10 for header
}
else
{
intPos = (int)id3v2.TagSize + 20; //+20 for header and footer
}
}
fs.Position = intPos;
fs.Read(bytHeader, 0, 4);
MPEGAudioFrame temp = new MPEGAudioFrame(bytHeader, 0);
if (temp.Valid == false)
{
if (Encoding.ASCII.GetString(bytHeader, 0, 3) == "ID3")
{
//Another ID3v2 Tag?
Console.WriteLine("Another ID3v2 tag was found after the initial one");
Console.WriteLine();
}
else if (Encoding.ASCII.GetString(bytHeader, 0, 3) == "APE")
{
//APETAGEX has appeared before audio data
Console.WriteLine("APEv2 Tag Found after ID3v2 tag");
Console.WriteLine();
}
else
{
//Unknown - Somthing is here that is not supposed to be
Console.WriteLine("Garbage found after ID3v2 tag");
Console.WriteLine();
}
}
//ID3v2 Tag was not valid, so the reported size may not be the actual size. Search backwards to try and find the first mpeg audio frame.
if (!id3v2.Valid)
{
//Search Backwards (Max Search 16384)
int intPosPrev = intPos;
int maxPos = intPos - 16384;
if (maxPos < 0)
{
maxPos = 0;
}
do
{
fs.Position = intPos;
fs.Read(bytHeader, 0, 4);
firstFrame = new MPEGAudioFrame(bytHeader, intPos);
if (firstFrame.Valid)
{
nextFrame = intPos + firstFrame.FrameSize;
fs.Position = nextFrame;
bytHeader = new byte[4]; //Reset bytHeader array
fs.Read(bytHeader, 0, 4);
MPEGAudioFrame SecondHeader = new MPEGAudioFrame(bytHeader, nextFrame);
if (SecondHeader.Valid)
{
Valid = true;
break;
}
else
{
//The next frame did not appear valid - reset stream position
fs.Position = intPos;
}
}
intPos--;
} while (!Valid && (fs.Position >= maxPos) && intPos >= 0);
if (!Valid)
{
intPos = intPosPrev;
}
}
//Search Forwards
do
{
fs.Position = intPos;
fs.Read(bytHeader, 0, 4);
firstFrame = new MPEGAudioFrame(bytHeader, intPos);
if (firstFrame.Valid)
{
nextFrame = intPos + firstFrame.FrameSize;
fs.Position = nextFrame;
bytHeader = new byte[4]; //Reset bytHeader array
fs.Read(bytHeader, 0, 4);
MPEGAudioFrame SecondHeader = new MPEGAudioFrame(bytHeader, nextFrame);
if (SecondHeader.Valid)
{
Valid = true;
break;
}
else
{
//The next frame did not appear valid - reset stream position
fs.Position = intPos;
}
}
intPos++;
}while (!Valid && (fs.Position != fs.Length));
// If the current file stream position is equal to the length,
// that means that we've read the entire file and it's not a valid MP3 file
if (Valid && (fs.Position != fs.Length))
{
intPos += 4; //Bypass the 4 byte header
//The following is retrieved from XING SDK //http://www.mp3-tech.org/programmer/decoding.html
if (firstFrame.getVersion() == 1.0) //MPEG Version 1
{
if (firstFrame.ChannelModeIndex == 3) //Single Channel (Mono)
{
intPos += 17;
}
else
{
intPos += 32;
}
}
else //MPEG Version 2.0 or 2.5
{
if (firstFrame.ChannelModeIndex == 3) //Single Channel (Mono)
{
intPos += 9;
}
else
{
intPos += 17;
}
}
// Check to see if the MP3 has a variable bitrate
fs.Position = intPos;
//fs.Read(bytVBitRate,0,12);
//bVBR = LoadVBRHeader(bytVBitRate);
vbrFrameInfo = new VBRHeader(fs, (long)intPos);
// Find the last Audio Frame of the MP3
findLastFrame(fs);
// Once the file's read in, then assign the properties of the file to the public variables
intBitRate = getBitrate();
intFrequency = firstFrame.getFrequency();
strMode = firstFrame.getChannelMode();
intLength = getLengthInSeconds();
strLengthFormatted = getFormattedLength();
fs.Close();
}
}