public MpegAudio(String path)
{
const int dataLength = MaxMpegFrameLength * 2;
ResetData();
using (BinaryReader br = new BinaryReader(File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
int startPos = ID3v2.GetTagSize(br.BaseStream);
// Get file length
m_FileLength = br.BaseStream.Length;
// Seek past ID3v2 tag
br.BaseStream.Seek(startPos, SeekOrigin.Begin);
// Read first block of data and search for a frame
Byte[] data = br.ReadBytes(dataLength);
FindFrame(data, ref m_VBR);
m_VendorID = FindVendorID(data);
// Try to search in the middle of the file if no frame at the beginning found
if (!m_Frame.Found)
{
br.BaseStream.Seek((m_FileLength - startPos) / 2, SeekOrigin.Begin);
data = br.ReadBytes(dataLength);
FindFrame(data, ref m_VBR);
}
// Search for vendor ID at the end if CBR encoded
if (m_Frame.Found && String.IsNullOrEmpty(m_VendorID))
{
br.BaseStream.Seek(-(data.Length + ID3v1.GetTagSize(br.BaseStream)), SeekOrigin.End);
data = br.ReadBytes(dataLength);
FindFrame(data, ref m_VBR);
m_VendorID = FindVendorID(data);
}
}
if (m_Frame.Found == false)
{
ResetData();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="BasicLameTagReader"/> class.
/// </summary>
/// <param name="path">The path.</param>
public BasicLameTagReader(string path)
{
if (string.IsNullOrEmpty(path))
{
throw new ArgumentNullException("path");
}
// Initialize
_isLameTagFound = true;
_tag = new LameTag();
using (BinaryReader br = new BinaryReader(File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
int startPos = ID3v2.GetTagSize(br.BaseStream);
// Seek past ID3v2 tag
br.BaseStream.Seek(startPos, SeekOrigin.Begin);
// Get StartOfFile structure
StartOfFile startOfFile = StartOfFile.FromBinaryReader(br);
// Seek past ID3v2 tag
br.BaseStream.Seek(startPos, SeekOrigin.Begin);
string info1 = Encoding.ASCII.GetString(startOfFile.Info1);
string info2 = Encoding.ASCII.GetString(startOfFile.Info2);
string info3 = Encoding.ASCII.GetString(startOfFile.Info3);
if (info1 == "Xing" || info1 == "Info")
{
br.BaseStream.Seek(Info1Offset, SeekOrigin.Current);
}
else if (info2 == "Xing" || info2 == "Info")
{
br.BaseStream.Seek(Info2Offset, SeekOrigin.Current);
}
else if (info3 == "Xing" || info3 == "Info")
{
br.BaseStream.Seek(Info3Offset, SeekOrigin.Current);
}
else
{
_isLameTagFound = true;
}
// Read LAME tag structure
br.BaseStream.Seek(LAMETagOffset, SeekOrigin.Current);
_tag = LameTag.FromBinaryReader(br);
// Read old LAME header
br.BaseStream.Seek(0 - Marshal.SizeOf(typeof(LameTag)), SeekOrigin.Current);
OldLameHeader oldLameHeader = OldLameHeader.FromBinaryReader(br);
_versionStringNonLameTag = Encoding.ASCII.GetString(oldLameHeader.VersionString);
}
// Set version string
if (_tag.VersionString[1] == '.')
{
byte[] versionString = new byte[6];
int i;
for (i = 0; i < 4 || (i == 4 && _tag.VersionString[i] == 'b'); i++)
{
versionString[i] = _tag.VersionString[i];
}
Array.Resize(ref versionString, i);
_versionString = Encoding.ASCII.GetString(versionString);
}
else
{
_versionString = "";
}
// If encoder is not LAME, set IsLameTagFound to false
// TODO : How about other encoders that use the LAME tag?
if (Encoding.ASCII.GetString(_tag.Encoder) != "LAME")
{
_isLameTagFound = false;
}
// Set preset WORD
_preset = (ushort)(((_tag.Surround_Preset[0] << 8) + _tag.Surround_Preset[1]) & 0x07FF);
// Guess preset
_presetGuess = (new PresetGuesser()).GuessPreset(
VersionStringNonLameTag, /*m_Tag.VersionString*/
_tag.Bitrate,
_tag.Quality,
_tag.TagRevision_EncodingMethod,
_tag.NoiseShaping,
_tag.StereoMode,
_tag.EncodingFlags_ATHType,
_tag.Lowpass,
out _isPresetGuessNonBitrate);
}
