//! analyze frame header.
private bool checkID3v1(ref BinaryReader br, ref sMP3Data data, BinaryReader tag_check)
{
byte[] tag_byte = new byte[3];
tag_check.Read(tag_byte, 0, 3);
string tag_name = Encoding.ASCII.GetString(tag_byte);
Console.Write("tag：{0}\n", tag_name);
//! "TAG" check.
if (tag_name == "TAG")
{
return true;
}
return false;
}
//! analyze ID3v2tag.
private bool analyzeID3v2(ref FileStream fs, ref BinaryReader br, ref sMP3Data data)
{
BinaryReader tag_br = new BinaryReader(fs);
byte[] tag_byte = new byte[3];
tag_br.Read(tag_byte, 0, 3);
string tag_name = Encoding.ASCII.GetString(tag_byte);
Console.Write("tag：{0}\n", tag_name);
//! "ID3" check.
if (tag_name != "ID3")
{
data.tag_name = "";
return true;
}
data.mb_HeaderID3v2 = new byte[10];
br.Read(data.mb_HeaderID3v2, 0, 10);
Console.Write("header_byte：0x");
for (int count = 0; count < 10; count++)
{
Console.Write("{0:x2}", data.mb_HeaderID3v2[count]);
}
Console.Write("\n");
//! header name.
string header_name = Encoding.ASCII.GetString(data.mb_HeaderID3v2, 0, 3);
Console.Write("header_name：{0}\n", header_name);
//! header version.
data.mh_ID3v2Version = BitConverter.ToInt16(data.mb_HeaderID3v2, 3);
Console.Write("header_version：0x{0:x8}\n", data.mh_ID3v2Version);
if (data.mh_ID3v2Version != 2)
{
return false;
}
//! header flag.
Console.Write("header_flag：0x{0:x8}\n", data.mb_HeaderID3v2[5]);
//! header size.
byte[] byte_switch = new byte[4];
byte byte_set_offset = 0;
for (int count = 0; count < 4; count++)
{
byte_switch[count] = (byte)(data.mb_HeaderID3v2[count + 6] & 0x7f);
}
for (int count = 0; count < 3; count++)
{
byte_set_offset = (byte)(byte_switch[2-count] << (7-count));
byte_switch[3-count] = (byte)(byte_switch[3-count] | byte_set_offset);
byte_switch[2-count] = (byte)(byte_switch[2-count] >> (1+count));
}
common_func.converIntValue(ref data.mh_ID3v2Size, byte_switch, 0);
Console.Write("header_size：{0}\n", data.mh_ID3v2Size);
Console.Write("header_size ：0x{0:x2}{1:x2}{2:x2}{3:x2}\n", data.mb_HeaderID3v2[6], data.mb_HeaderID3v2[7], data.mb_HeaderID3v2[8], data.mb_HeaderID3v2[9]);
Console.Write("header_switch：0x{0:x2}{1:x2}{2:x2}{3:x2}\n", byte_switch[0], byte_switch[1], byte_switch[2], byte_switch[3]);
data.mb_ID3v2TagInfo = new byte[data.mh_ID3v2Size];
br.Read(data.mb_ID3v2TagInfo, 0, data.mh_ID3v2Size);
return true;
}
//! search ID3v2tag info.
public bool searchID3v2(ref byte[] byte_info, ref int info_size, sMP3Data data, string tag)
{
int frame_check = 0;
byte[] byte_frame = new byte[6];
string frame_name;
byte[] byte_switch = new byte[4];
int frame_size = 0;
int compare = 0;
while (true)
{
//! frame size over break.
if (frame_check >= data.mh_ID3v2Size) break;
Console.Write("frame_check：{0}\n", frame_check);
//! frame name & size check.
for (int count = 0; count < 6; count++)
{
byte_frame[count] = data.mb_ID3v2TagInfo[frame_check + count];
}
Console.Write("byte_frame：0x{0:x2}{1:x2}{2:x2}{3:x2}{4:x2}{5:x2}\n", byte_frame[0], byte_frame[1], byte_frame[2], byte_frame[3], byte_frame[4], byte_frame[5]);
//! frame name check.
frame_name = Encoding.ASCII.GetString(byte_frame, 0, 3);
Console.Write("frame_name：{0}\n", frame_name);
byte_frame[2] = (byte)(byte_frame[2] & 0x00);
for (int count = 0; count < 4; count++)
{
byte_switch[count] = byte_frame[count + 2];
}
common_func.converIntValue(ref frame_size, byte_switch, 0);
Console.Write("frame_size：{0}\n", frame_size);
compare = string.Compare(tag, frame_name);
if (compare == 0)
{
byte_info = new byte[frame_size];
info_size = frame_size;
Array.Copy(data.mb_ID3v2TagInfo, frame_check + 6, byte_info, 0, frame_size);
return true;
}
frame_check += frame_size + 6;
}
return false;
}
//! analyze frame header.
private bool analyzeFrameHeader(ref BinaryReader br, ref sMP3Data data)
{
//! header 4byte.
byte[] header_byte = new byte[4];
br.Read(header_byte, 0, 4);
common_func.converIntValue(ref data.frame_bit, header_byte, 0);
Console.Write("header：0x{0:x8} {1}\n", data.frame_bit, sizeof(int));
//! check first bit.
int check_bit = data.frame_bit >> 21;
check_bit = check_bit & 0x00000FFF;
if (check_bit == 0)
{
return false;
}
//! get ID-bit.
int mpeg_ver = data.frame_bit >> 19;
mpeg_ver = mpeg_ver & 0x00000003;
data.mpeg_ver = (eMPEGVer)mpeg_ver;
Console.Write("mpeg_ver：0x{0:x8}\n", mpeg_ver);
//! get Layer-bit.
int layer_bit = data.frame_bit >> 17;
layer_bit = layer_bit & 0x00000003;
data.layer_bit = (eLayerBit)layer_bit;
Console.Write("layer_bit：0x{0:x8}\n", layer_bit);
//! Protection-Bit.
int protection_bit = data.frame_bit >> 16;
protection_bit = protection_bit & 0x00000001;
data.protection_bit = (eProtectionBit)protection_bit;
Console.Write("protection_bit：0x{0:x8}\n", protection_bit);
//! BitRateTable.
int bitrate = data.frame_bit >> 12;
bitrate = bitrate & 0x0000000F;
if (data.mpeg_ver == eMPEGVer.First)
{
switch (data.layer_bit)
{
case eLayerBit.Layer1:
data.bitrate = m_BitRateTable[0][bitrate];
break;
case eLayerBit.Layer2:
data.bitrate = m_BitRateTable[1][bitrate];
break;
case eLayerBit.Layer3:
data.bitrate = m_BitRateTable[2][bitrate];
break;
default:
Console.Write("Get Bitrate : None Layer\n");
break;
}
}
else if (data.mpeg_ver == eMPEGVer.Second || data.mpeg_ver == eMPEGVer.SecondHalf)
{
switch (data.layer_bit)
{
case eLayerBit.Layer1:
data.bitrate = m_BitRateTable[3][bitrate];
break;
case eLayerBit.Layer2:
case eLayerBit.Layer3:
data.bitrate = m_BitRateTable[4][bitrate];
break;
default:
Console.Write("Get Bitrate : None Layer\n");
break;
}
}
else
{
Console.Write("MPEG ver None BitrateTable\n");
return false;
}
Console.Write("bitrate：{0}\n", data.bitrate);
//! Sampling Frequency.
int sampling = data.frame_bit >> 10;
sampling = sampling & 0x00000003;
switch (data.mpeg_ver)
{
case eMPEGVer.First:
data.samplingrate = m_SamplingRateTable[0][sampling];
break;
case eMPEGVer.Second:
data.samplingrate = m_SamplingRateTable[1][sampling];
break;
case eMPEGVer.SecondHalf:
data.samplingrate = m_SamplingRateTable[2][sampling];
break;
default:
Console.Write("MPEG ver None SamplingRateTable\n");
break;
}
Console.Write("sampling：{0}\n", data.samplingrate);
//! Padding Bit.
int padding_bit = data.frame_bit >> 9;
padding_bit = padding_bit & 0x00000001;
data.padding_bit = padding_bit;
Console.Write("padding_bit：0x{0:x8}\n", data.padding_bit);
//! Private Bit.
int private_bit = data.frame_bit >> 8;
private_bit = private_bit & 0x00000001;
data.private_bit = private_bit;
Console.Write("private_bit：0x{0:x8}\n", data.private_bit);
//! Mode Bit.
int mode_bit = data.frame_bit >> 6;
mode_bit = mode_bit & 0x00000003;
data.mode_bit = (eModeBit)mode_bit;
Console.Write("mode_bit：0x{0:x8}\n", mode_bit);
//! ModeExtension Bit.
int modeEx_bit = data.frame_bit >> 4;
modeEx_bit = modeEx_bit & 0x00000003;
data.modeEx_bit = (eModeExtension)modeEx_bit;
Console.Write("modeEx_bit：0x{0:x8}\n", modeEx_bit);
//! Copyright.
int copyright_bit = data.frame_bit >> 3;
copyright_bit = copyright_bit & 0x00000001;
data.copyright_bit = copyright_bit;
Console.Write("copyright_bit：0x{0:x8}\n", data.copyright_bit);
//! Original Check.
int original_bit = data.frame_bit >> 2;
original_bit = original_bit & 0x00000001;
data.original_bit = original_bit;
Console.Write("original_bit：0x{0:x8}\n", data.original_bit);
//! Emphasis Bit.
int emphasis_bit = data.frame_bit & 0x00000003;
data.emphasis_bit = (eEmphasis)emphasis_bit;
Console.Write("emphasis_bit：0x{0:x8}\n", emphasis_bit);
//! Frame Size.
switch (data.layer_bit)
{
case eLayerBit.Layer1:
data.frame_size = ((12 * 1000 * data.bitrate / data.samplingrate) + data.padding_bit) * 4;
break;
case eLayerBit.Layer2:
data.frame_size = (144 * 1000 * data.bitrate / data.samplingrate) + data.padding_bit;
break;
case eLayerBit.Layer3:
if (data.mpeg_ver == eMPEGVer.First)
{
data.frame_size = (144 * 1000 * data.bitrate / data.samplingrate) + data.padding_bit;
}
else
{
data.frame_size = (72 * 1000 * data.bitrate / data.samplingrate) + data.padding_bit;
}
break;
default:
Console.Write("MPEG ver None Frame Size\n");
break;
}
Console.Write("frame_size：{0}\n", data.frame_size);
byte[] frame_size_byte = new byte[data.frame_size-4];
br.Read(frame_size_byte, 0, data.frame_size-4);
return true;
#if false
//! frame tag checktest.
byte[] get_info = null;
int info_size = 0;
bool ret = searchID3v2(ref get_info, ref info_size, data, "TSS");
if (ret)
{
string tss_name;
tss_name = Encoding.ASCII.GetString(get_info, 1, info_size-1);
Console.Write("string_code_bit：0x{0:x2}\n", get_info[0]);
Console.Write("tss_name：{0}\n", tss_name);
}
#endif
}
//! analyze start mp3.
public void readMp3Data(ref sMP3Data data, string filename)
{
//! file open.
FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
Console.Write("mp3 file name：{0}\n", filename);
//! analyze ID3v2tag.
FileStream tag_fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
bool ver_check = analyzeID3v2(ref tag_fs, ref br, ref data);
//! mp3 analyze version 2.2 only.
if (!ver_check)
{
return;
}
//! get header info.
while (true)
{
if (!analyzeFrameHeader(ref br, ref data))
{
break;
}
}
}
