any link or good idea for reading mpeg4 header in c#??
octavia 0 Light Poster
Diamonddrake 397 Master Poster
I hear that quicktime has a COM api that allows for automatic parsing of file headers. But it's unconfirmed. Its just an idea. there is a Mpeg 1/2 class floating around.
This link might help It has a good amount of information about the mpeg-4 file format.
Parsing a header is complicated, especially with video headers as the container file has a header, and each stream has a header. So even with the most simple video there are actually 3 headers to parse. The container header, the video header, and the audio header. Its a serious task and not something you will throw together very quickly, But good luck.
octavia 0 Light Poster
Hi Diamonddrake, Thanks for your reply
Yes, it's a bit serious thing. Actually i want to know my video file resolution, bitrate,audio channel, compression used .. etc.
I already have some code which can read .mp3 file format. but i really don't know about .mp4 .
will get on mpeg1/2 .--
Diamonddrake 397 Master Poster
I found this for mpeg 1/2
public class MPEGInfo
{
#region index structures from mpgtx source
int[, ,] BitRateIndex = new int[2, 3, 16]
{
{ // MPEG 1
{0,32,64,96,128,160,192,224,256,288,320,352,384,416,448,0}, // layer 1
{0,32,48,56, 64, 80, 96,112,128,160,192,224,256,320,384,0}, // layer 2
{0,32,40,48, 56, 64, 80, 96,112,128,160,192,224,256,320,0} // layer 3
},
{// MPEG 2 or 2.5
{0,32,48,56, 64, 80, 96,112,128,144,160,176,192,224,256,0}, // layer 1
{0, 8,16,24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0}, // layer 2
{0, 8,16,24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160,0} // layer 3
}
};
int[,] SamplingIndex = new int[3, 4]
{
{44100,48000,32000,0}, // mpeg 1
{22050,24000,16000,0}, // mpeg 2
{11025,12000, 8000,0} // mpeg 2.5
};
double[] FrameRateIndex = new double[9]
{
0d, 24000d/1001d, 24d, 25d,
30000d/1001d, 30d, 50d,
60000d/1001d, 60d
};
string[] AspectRatioIndex = new string[5]
{
"Invalid",
"1/1 (VGA)",
"4/3 (TV)",
"16/9 (Large TV)",
"2.21/1 (Cinema)"
};
public string[] ModeIndex = new string[4] // these can change anytime specs change so be careful
{
"Stereo",
"Joint Stereo",
"Dual Channel",
"Mono",
};
public string[] EmphasisIndex = new string[4] // same as above
{
"No Emphasis",
"50/15 Micro seconds",
"Unknown",
"CCITT J 17",
};
#endregion
#region properties
public class Video
{
public int GopHeaders;
public int Height; // px
public int Width;
public double FrameRate; // fps
public int AspectRatioCode;
public string AspectRatio;
public int BitRate;
public double Duration; // seconds
public double MuxRate;
public int ChromaFormat;
public string ChromaFormatText;
public int Format;
public string FormatText;
public int Frames;
public int Version = 1; // by default its 1
}
public Video VideoInfo;
public class Audio
{
public double Version;
public int Layer;
public bool Protected;
public int BitRate;
public float ByteRate;
public int SamplingRate;
public bool Padding;
public int ModeCode;
public int ModeXt;
public bool Copyright;
public int EmphasisIndex;
public bool Original;
public int FrameLength;
// seconds; duration = file size / bit rate but from what i understand there is a timestamp
// for initial and one for when video ends, so accurate duration = timestamp end - timestamp start
public double Duration;
public int Frames;
}
public Audio AudioInfo;
#endregion
public bool EnableTrace; // debugging purposes
const byte PADDING_PACKET = 0xBE; // use these to compare instead of bytes every time
const byte VIDEO_PACKET = 0xE0;
const byte AUDIO_PACKET = 0xC0;
const byte SYSTEM_PACKET = 0xBB;
const double FLOAT_0x10000 = (double)((UInt32)1 << 16); // unsigned long in c++ is UInt32 in c#
const UInt32 STD_SYSTEM_CLOCK_FREQ = (UInt32)90000;
const int BUFFER_SIZE = 8192; // 8K buffer
int _mpegVersion = 1;
long _fileSize;
double _initialTS; // needed to fix video/audio duration
bool _mpeg2Found; // switch needed to fix video duration
byte[] _backwardBuffer;
byte[] _forwardBuffer;
FileStream _fs;
BinaryReader _br;
public MPEGInfo(string file)
{
if (!File.Exists(file))
{
return;
}
_fs = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
_br = new BinaryReader(_fs);
}
public void Parse()
{
if (_br != null)
{
_backwardBuffer = new byte[BUFFER_SIZE];
_forwardBuffer = new byte[BUFFER_SIZE];
_fileSize = _fs.Length;
VideoInfo = new Video();
AudioInfo = new Audio();
ParseVideo(0);
//_br.BaseStream.Seek(0, SeekOrigin.Begin); // go back to the start (redundant now)
ParseAudio();
//_br.BaseStream.Seek(0, SeekOrigin.Begin); // go back to the start
ParseSystem(0);
}
_br.Close();
_fs.Close();
}
int _backwardBufferStart = 0;
int _backwardBufferEnd = 0;
byte GetByteBackwards(int offset)
{
int pos = -1;
if (offset >= _backwardBufferEnd || offset < _backwardBufferStart) // need new buffer
{
//Trace(string.Format("-debug- new buffer needed; offset: {0}, buffer start: {1}, buffer end: {2}", offset,
// _backwardBufferStart, _backwardBufferEnd));
pos = offset - BUFFER_SIZE + 1;
if (pos < 0) { pos = 0; }
//Trace(string.Format("-debug- position: {0}", pos));
_backwardBufferStart = pos;
_backwardBufferEnd = offset;
//Trace(string.Format("-debug- buffer start: {0}, buffer end: {1}",
// _backwardBufferStart, _backwardBufferEnd));
_br.BaseStream.Seek(pos, SeekOrigin.Begin);
_br.Read(_backwardBuffer, 0, BUFFER_SIZE);
}
//Trace(string.Format("-debug- offset: {0}, buffer start: {1}",
// offset, _backwardBufferStart));
// got new buffer or still in range
return _backwardBuffer[offset - _backwardBufferStart];
}
int _forwardBufferStart = 0;
int _forwardBufferEnd = 0;
byte GetByte(int offset)
{
int pos = -1;
if (offset >= _forwardBufferEnd || offset < _forwardBufferStart) // need new buffer
{
//Trace(string.Format("-debug- new f buffer needed; offset: {0}, buffer start: {1}, buffer end: {2}", offset,
// _forwardBufferStart, _forwardBufferEnd));
pos = offset + BUFFER_SIZE;
if (pos > _fileSize) { pos = (int)_fileSize; }
//Trace(string.Format("-debug- f position: {0}", pos));
_forwardBufferStart = offset;
_forwardBufferEnd = pos;
//Trace(string.Format("-debug- f buffer start: {0}, buffer end: {1}",
// _forwardBufferStart, _forwardBufferEnd));
_br.BaseStream.Seek(offset, SeekOrigin.Begin);
_br.Read(_forwardBuffer, 0, BUFFER_SIZE);
}
//Trace(string.Format("-debug- f offset after creating/if statements: {0}, buffer start: {1}",
// offset, _forwardBufferStart));
// got new buffer or still in range
return _forwardBuffer[offset - _forwardBufferStart];
}
int GetSize(int offset)
{
return GetByte(offset) * 256 + GetByte(offset + 1);
}
/// <summary>
/// Find the specified marker given a starting position
/// </summary>
/// <param name="offset">Position to start searching from</param>
/// <param name="marker">Marker to search for</param>
/// <returns>True and the offset if the maker is found</returns>
bool EnsureMPEG(out int offset, byte marker)
{
offset = 0;
for (int i = 0; i < _fileSize - 4; i++)
{
if (GetByte(i) == 0x00
&& GetByte(i + 1) == 0x00
&& GetByte(i + 2) == 0x01
&& GetByte(i + 3) == marker)
{
offset = i;
return true;
}
}
return false;
}
/// <summary>
/// Find a specific marker by going through the file in reverse
/// TODO: Improve this (GetByte() is slow when using this method because it seeks from the start
/// </summary>
/// <param name="offset">Position to start searching from</param>
/// <param name="marker">Marker to search for</param>
/// <returns>Position of the marker</returns>
int FindMarkerBackwards(int offset, byte marker)
{
for (int i = offset; i > 0; i--)
{
if (GetByteBackwards(i) == 0x00
&& GetByteBackwards(i + 1) == 0x00
&& GetByteBackwards(i + 2) == 0x01
&& GetByteBackwards(i + 3) == marker)
{
return i;
}
}
return -1;
}
bool MarkerExistsAt(out int offset, byte marker, int from) // self explanatory / see above
{
offset = -1;
for (int i = from; i < _fileSize - 4; i++)
{
if (GetByte(i) == 0x00
&& GetByte(i + 1) == 0x00
&& GetByte(i + 2) == 0x01
&& GetByte(i + 3) == marker)
{
offset = i;
return true;
}
}
return false;
}
int FindNextMarker(int from, byte marker) // overloaded method / see above
{
int offset = from;
while (from >= 0 && from < _fileSize - 4)
{
offset = FindNextMarker(from);
if (offset == -1)
{
return -1;
}
else if (MarkerExistsAt(out offset, marker, from))
{
return offset;
}
else
{
from++;
}
}
return -1;
}
int FindNextMarker(int from, ref byte marker) // see above
{
int offset = FindNextMarker(from);
if (offset > -1)
{
marker = GetByte(offset + 3);
return offset;
}
return -1;
}
int FindNextMarker(int from) // see above
{
int offset;
for (offset = from; offset < (_fileSize - 4); offset++)
{
if (
(GetByte(offset + 0) == 0x00) &&
(GetByte(offset + 1) == 0x00) &&
(GetByte(offset + 2) == 0x01))
{
return offset;
}
}
return -1;
}
bool hasAudio = false;
void ParseSystem(int offset)
{
bool keepGoing = true;
byte mark = 0x00;
if (EnsureMPEG(out offset, 0xBA)) // make sure we'r parsing a mpeg header
{
//FindMuxRate(offset + 4);
int packLength = 0;
int packetSize = 0;
byte packetType = new byte();
while (keepGoing)
{
offset = FindNextMarker(offset, ref mark);
if (offset == -1)
{
break; // valid marker not found
}
if (mark == VIDEO_PACKET || mark == AUDIO_PACKET)
{
break; // end of system header
}
if (mark == PADDING_PACKET)
{
offset += GetSize(offset + 4);
continue;
}
if (mark == 0xBA)
{
FindMuxRate(offset + 4);
offset += 12;
continue;
}
if (mark != SYSTEM_PACKET)
{
offset += 4;
continue;
}
int startOfPack = FindNextMarker(offset, 0xBA);
if (startOfPack != -1)
{
if ((GetByte(startOfPack + 4) & 0xF0) == 0x20)
{
packLength = 12; // mpeg 1
}
else
{
if ((GetByte(startOfPack + 4) & 0xC0) == 0x40)
{
// mpeg 2 pack + stuffing
packLength = 14 + (GetByte(startOfPack + 13) & 0x07);
}
else
{
packLength = 12; // somethings not right
}
}
}
if (startOfPack == -1 || (startOfPack + packLength != offset))
{
//Trace(string.Format("-debug- startOfPack: {0}, packLength: {1}, offset: {2}",
// startOfPack, packLength, offset));
startOfPack = offset;
//return; keep going anyway
}
// TODO: Implement ParseSystemPacket
packetSize = GetSize(offset + 4);
packetType = GetByte(offset + 12);
//Trace(string.Format("-debug- packetSize: {0}, packetType: {1}, packLength: {2}, offset: {3}",
// packetSize, packetType, packLength, offset));
if (GetByte(offset + 15) == AUDIO_PACKET || GetByte(offset + 15) == VIDEO_PACKET)
{
packetType = VIDEO_PACKET;
}
if (packetType == AUDIO_PACKET)
{
// TODO: Implement this if needed
}
else if (packetType == VIDEO_PACKET)
{
// here we are finally!, this part will fix up the durations
if (packLength == 12)
{
_initialTS = ReadTS(offset - packLength); // find the initial timestamp
_mpeg2Found = false; // pack 12 so its not mpeg 2
}
else
{
_initialTS = ReadTSMpeg2(offset - packLength);
_mpeg2Found = true;
}
//Trace(string.Format("-debug- initial ts: {0}", _initialTS));
}
offset += 4; // keep going
}
}
/* hopefully it gets to here without crashing :P
* start searching from the end of the file and -12 because a pack is usually 12 bytes long
*/
int lastPack = FindMarkerBackwards((int)_fileSize - 13, 0xBA);
//Trace(string.Format("-debug- lastPack: {0}", lastPack));
double duration;
if ((GetByte(lastPack + 4) & 0xF0) == 0x20)
{
duration = ReadTS(lastPack + 4); // mpeg 1
}
else
{
lastPack = FindMarkerBackwards((int)_fileSize - 8, 0xB8);
//Trace(string.Format("-debug- lastPack 2: {0}", lastPack));
if (((GetByte(lastPack + 4) & 0xC0) == 0x40) || _mpeg2Found)
{
lastPack = FindMarkerBackwards((int)_fileSize - 8, 0xBA);
//Trace(string.Format("-debug- lastPack 3: {0}", lastPack));
duration = ReadTSMpeg2(lastPack + 4);
}
else
{
duration = ReadTSMpeg2(lastPack + 4);
}
}
//Trace(string.Format("-debug- duration before: {0}", duration));
duration -= _initialTS; // fix up the duration
//Trace(string.Format("-debug- duration after: {0}", duration));
if (this.VideoInfo.Duration > 0)
{
if (this.VideoInfo.Duration > duration)
{
this.VideoInfo.Duration = duration; // only update if existing is more than current
}
}
//Trace(string.Format("-debug- video duration: {0}", SecondsToHMS(this.VideoInfo.Duration)));
}
double ReadTS(int offset)
{
byte highBit;
UInt32 low4Bytes; // needs to be UInt32 otherwise won't work
double ts;
highBit = (byte)((GetByte(offset) >> 3) & 0x01);
low4Bytes = (UInt32)(((GetByte(offset) >> 1) & 0x03) << 30);
low4Bytes |= (UInt32)(GetByte(offset + 1) << 22);
low4Bytes |= (UInt32)((GetByte(offset + 2) >> 1) << 15);
low4Bytes |= (UInt32)(GetByte(offset + 3) << 7);
low4Bytes |= (UInt32)(GetByte(offset + 4) >> 1);
ts = (double)(highBit * FLOAT_0x10000 * FLOAT_0x10000);
ts += (double)(low4Bytes);
ts /= (double)STD_SYSTEM_CLOCK_FREQ;
return ts;
}
double ReadTSMpeg2(int offset)
{
byte highBit;
UInt32 low4Bytes;
UInt32 sysClockRef;
double ts;
highBit = (byte)((GetByte(offset) & 0x20) >> 5);
low4Bytes = (UInt32)(((GetByte(offset) & 0x18) >> 3) << 30);
low4Bytes |= (UInt32)((GetByte(offset) & 0x03) << 28);
low4Bytes |= (UInt32)(GetByte(offset + 1) << 20);
low4Bytes |= (UInt32)((GetByte(offset + 2) & 0xF8) << 12);
low4Bytes |= (UInt32)((GetByte(offset + 2) & 0x03) << 13);
low4Bytes |= (UInt32)(GetByte(offset + 3) << 5);
low4Bytes |= (UInt32)(GetByte(offset + 4) >> 3);
sysClockRef = (UInt32)((GetByte(offset + 4) & 0x3) << 7);
sysClockRef |= (UInt32)((GetByte(offset + 5) >> 1));
ts = (double)(highBit * FLOAT_0x10000 * FLOAT_0x10000);
ts += (double)low4Bytes;
// TODO: fix this up (confirm with mpgtx first)
if (sysClockRef == 0)
{
ts /= (double)STD_SYSTEM_CLOCK_FREQ;
}
else
{
ts /= (double)STD_SYSTEM_CLOCK_FREQ;
}
return ts;
}
void FindMuxRate(int offset)
{
int muxrate = 0;
if ((GetByte(offset) & 0xC0) == 0x40)
{
muxrate = GetByte(offset + 6) << 14;
muxrate |= GetByte(offset + 7) << 6;
muxrate |= GetByte(offset + 8) >> 2;
}
else
{
if ((GetByte(offset) & 0xF0) != 0x20)
{
//Trace("-debug- invalid offset for mux rate");
}
muxrate = (GetByte(offset + 5) & 0x7F) << 15;
muxrate |= (GetByte(offset + 6) << 7);
muxrate |= (GetByte(offset + 7) >> 1);
}
muxrate *= 50;
this.VideoInfo.MuxRate = (double)((muxrate * 8.0) / 1000000.0);
//Trace(string.Format("system mux rate: {0} mbps", this.VideoInfo.MuxRate.ToString("n2")));
}
void ParseAudio()
{
int offset = 0;
hasAudio = false;
// Trace("starting to parse audio");
offset = FindNextMarker(0, 0xC0); // find the audio marker
if (offset <= -1)
{
return;
}
if (offset > -1)
{
offset += 13;
}
// Trace(string.Format("offset of audio: {0}", offset));
if (!ParseAudio(offset))
{
// Trace("failed to parse audio");
while ((offset < _fileSize - 10) && !hasAudio) // go through the file until we find an audio marker
{
// Trace(string.Format("looping to find audio offset: {0}", offset));
if ((GetByte(offset) == 0xFF) && (GetByte(offset + 1) & 0xF0) == 0xF0) // found the proper sequence
{
if (ParseAudio(offset))
{
// Trace("found audio");
//this.AudioInfo.Frames++; this doesn't work right
hasAudio = true;
}
}
offset++; // try next offset
}
}
// Trace(string.Format("-debug- audio frames: {0}", this.AudioInfo.Frames));
}
bool ParseAudio(int offset)
{
hasAudio = false;
bool mpeg25 = false;
if ((GetByte(offset + 0) != 0xFF) || ((GetByte(offset + 1) & 0xF0) != 0xF0)) // see if this has mpeg 2.5
{
if ((GetByte(offset + 0) != 0xFF) || ((GetByte(offset + 1) & 0xE0) != 0xE0))
{
return false; // invalid sequence exit and try a different offset
}
else
{
mpeg25 = true;
}
}
// Trace(string.Format("-debug- offset: {0}", offset));
// Trace(string.Format("-debug- mpeg25: {0}", mpeg25));
if (Convert.ToBoolean((GetByte(offset + 1) & 0x08)))
{
if (!mpeg25)
{
this.AudioInfo.Version = 1.0d;
}
else
{
// Trace(string.Format("-debug- invalid 01"));
return false; // invalid version exit and try a different offset
}
}
else
{
if (!mpeg25)
{
this.AudioInfo.Version = 2.0d;
}
else
{
this.AudioInfo.Version = 3.0d; // for 2.5
}
}
// Trace(string.Format("-debug- audio version: {0}", this.AudioInfo.Version));
this.AudioInfo.Layer = (GetByte(offset + 1) & 0x06) >> 1;
switch (this.AudioInfo.Layer)
{
case 0:
this.AudioInfo.Layer = -1;
return false; // invalid layer exit and try a different offset
break;
case 1:
this.AudioInfo.Layer = 3;
break;
case 2:
this.AudioInfo.Layer = 2;
break;
case 3:
this.AudioInfo.Layer = 1;
break;
default:
this.AudioInfo.Layer = -1;
return false;
break;
}
// Trace(string.Format("-debug- audio layer: {0}", this.AudioInfo.Layer));
// TODO: confirm if 0 is true or 1 is true, mpgtx has 0 is false and 1 is true?
this.AudioInfo.Protected = Convert.ToBoolean(GetByte(offset + 1) & 0x01);
// Trace(string.Format("-debug- audio protection: {0}", this.AudioInfo.Protected));
int bitrateIndex = GetByte(offset + 2) >> 4;
int samplingIndex = (GetByte(offset + 2) & 0x0F) >> 2;
if (samplingIndex >= 3) { return false; } // invalid indexes, try another offset
if (bitrateIndex == 15) { return false; }
this.AudioInfo.BitRate = BitRateIndex[(int)this.AudioInfo.Version - 1, this.AudioInfo.Layer - 1, bitrateIndex];
this.AudioInfo.ByteRate = (float)((this.AudioInfo.BitRate * 1000) / 8.0d);
this.AudioInfo.SamplingRate = SamplingIndex[(int)this.AudioInfo.Version - 1, samplingIndex];
if (this.AudioInfo.BitRate <= 0
|| this.AudioInfo.ByteRate <= 0
|| this.AudioInfo.SamplingRate <= 0) { return false; }
//Trace(string.Format("-debug- audio bit rate: {0}", this.AudioInfo.BitRate));
//Trace(string.Format("-debug- audio byte rate: {0}", this.AudioInfo.ByteRate));
//Trace(string.Format("-debug- audio sampling rate: {0}", this.AudioInfo.SamplingRate));
if (Convert.ToBoolean(GetByte(offset + 2) & 0x02))
{
this.AudioInfo.Padding = true;
}
else
{
this.AudioInfo.Padding = false;
}
// Trace(string.Format("-debug- audio padding: {0}", this.AudioInfo.Padding));
this.AudioInfo.ModeCode = GetByte(offset + 3) >> 6;
// Trace(string.Format("-debug- audio mode: {0}", ModeIndex[this.AudioInfo.ModeCode]));
//TODO: add matching mode extension text
int modeExt = (GetByte(offset + 3) >> 4) & 0x03;
//Trace(string.Format("-debug- audio modeext: {0}", modeExt));
if (Convert.ToBoolean(GetByte(offset + 3) & 0x08))
{
this.AudioInfo.Copyright = true;
}
else
{
this.AudioInfo.Copyright = false;
}
//Trace(string.Format("-debug- audio copyright: {0}", this.AudioInfo.Copyright));
if (Convert.ToBoolean(GetByte(offset + 3) & 0x04))
{
this.AudioInfo.Original = true;
}
else
{
this.AudioInfo.Original = false;
}
// Trace(string.Format("-debug- audio original: {0}", this.AudioInfo.Original));
this.AudioInfo.EmphasisIndex = GetByte(offset + 3) & 0x03;
// Trace(string.Format("-debug- audio emphasis index: {0}",
//EmphasisIndex[this.AudioInfo.EmphasisIndex]));
if (this.AudioInfo.Version == 1)
{
if (this.AudioInfo.Layer == 1)
{
this.AudioInfo.FrameLength =
((48000 * this.AudioInfo.BitRate) / this.AudioInfo.SamplingRate)
+ 4 * Convert.ToInt32(this.AudioInfo.Padding);
}
else
{
this.AudioInfo.FrameLength =
((144000 * this.AudioInfo.BitRate) / this.AudioInfo.SamplingRate)
+ Convert.ToInt32(this.AudioInfo.Padding);
}
}
else if (this.AudioInfo.Version == 2)
{
if (this.AudioInfo.Layer == 1)
{
this.AudioInfo.FrameLength =
((24000 * this.AudioInfo.BitRate) / this.AudioInfo.SamplingRate)
+ 4 * Convert.ToInt32(this.AudioInfo.Padding);
}
else
{
this.AudioInfo.FrameLength =
((72000 * this.AudioInfo.BitRate) / this.AudioInfo.SamplingRate)
+ Convert.ToInt32(this.AudioInfo.Padding);
}
}
else
{
// Trace(string.Format("-debug- audio layer is invalid"));
return false;
}
if (this.AudioInfo.Protected)
{
// frame length sometimes gets offset by +- 2, got to find out why its happening, most likely its the protection switch (see above)
this.AudioInfo.FrameLength += 2;
}
// Trace(string.Format("-debug- audio frame length: {0}", this.AudioInfo.FrameLength));
this.AudioInfo.Duration = ((_fileSize * 1.0d) / this.AudioInfo.BitRate) * 0.008d;
// Trace(string.Format("-debug- audio duration: {0}", SecondsToHMS(this.AudioInfo.Duration)));
//CountAudioFrames();
hasAudio = true;
return hasAudio;
}
bool ParseVideo(int offset)
{
bool foundVideo = false;
// Trace(string.Format("-debug- file size: {0}", _fileSize));
if (EnsureMPEG(out offset, 0xB3))
{
foundVideo = true;
}
if (foundVideo)
{
// Trace(string.Format("-debug- offset: {0}", offset));
offset += 4; // move to the header location
this.VideoInfo.Width = GetSize(offset) >> 4;
this.VideoInfo.Height = GetSize(offset + 1) & 0x0FFF;
// Trace(string.Format("-debug- video height: {0}", this.VideoInfo.Height));
// Trace(string.Format("-debug- video width: {0}", this.VideoInfo.Width));
offset += 3;
int frameRateIndex = GetByte(offset) & 0x0F;
if (frameRateIndex > 8)
{
this.VideoInfo.FrameRate = 0.0d;
}
else
{
this.VideoInfo.FrameRate = FrameRateIndex[frameRateIndex];
}
// Trace(string.Format("-debug- video frame rate: {0}", this.VideoInfo.FrameRate));
this.VideoInfo.AspectRatioCode = (GetByte(offset) & 0xF0) >> 4;
if (this.VideoInfo.AspectRatioCode <= 4)
{
this.VideoInfo.AspectRatio = AspectRatioIndex[this.VideoInfo.AspectRatioCode];
}
else
{
this.VideoInfo.AspectRatio = "Unknown";
}
// Trace(string.Format("-debug- video aspect ratio code: {0}, string: {1}",
//this.VideoInfo.AspectRatioCode, this.VideoInfo.AspectRatio));
offset += 1;
this.VideoInfo.BitRate = GetSize(offset);
//Trace(string.Format("-debug- video bit rate: {0}", this.VideoInfo.BitRate));
this.VideoInfo.BitRate <<= 2;
//Trace(string.Format("-debug- video bit rate: {0}", this.VideoInfo.BitRate));
byte lastTwo = GetByte(offset + 2);
//Trace(string.Format("-debug- video lastTwo: {0}", lastTwo));
lastTwo >>= 6;
//Trace(string.Format("-debug- video lastTwo: {0}", lastTwo));
this.VideoInfo.BitRate |= lastTwo;
//Trace(string.Format("-debug- video bit rate: {0}", this.VideoInfo.BitRate));
this.VideoInfo.Duration = (_fileSize) /
((this.VideoInfo.BitRate * 400) / 8.0); // this gets fixed later when ParseSystem runs
//Trace(string.Format("-debug- video duration: {0}", SecondsToHMS(this.VideoInfo.Duration)));
//Trace(string.Format("-debug- video speed: {0} Mbps",
//(this.VideoInfo.BitRate / 2500).ToString("n2"))); // always 15mb/s?
// this part is needed to find video format and chroma format
byte mark = new byte();
while (true)
{
offset = FindNextMarker(offset, ref mark);
if (offset > -1)
{
if (mark == 0xB8) { break; }
switch (GetByte(offset + 3))
{
case 0xB5:
ParseExtension(offset);
break;
default:
break;
}
}
else
{
//Trace(string.Format("-debug- video offset is -1"));
break;
}
offset++;
}
switch (this.VideoInfo.ChromaFormat)
{
case 1:
this.VideoInfo.ChromaFormatText = "4:2:0";
break;
case 2:
this.VideoInfo.ChromaFormatText = "4:2:2";
break;
case 3:
this.VideoInfo.ChromaFormatText = "4:4:4";
break;
default:
this.VideoInfo.ChromaFormatText = "Unknown";
break;
}
switch (this.VideoInfo.Format)
{
case 0:
this.VideoInfo.FormatText = "Component";
break;
case 1:
this.VideoInfo.FormatText = "PAL";
break;
case 2:
this.VideoInfo.FormatText = "NTSC";
break;
case 3:
this.VideoInfo.FormatText = "SECAM";
break;
case 4:
this.VideoInfo.FormatText = "MAC";
break;
case 5:
this.VideoInfo.FormatText = "Unspecified";
break;
default:
this.VideoInfo.FormatText = "Unknown";
break;
}
//Trace(string.Format("-debug- video chroma format: {0} is {1}",
// this.VideoInfo.ChromaFormat, this.VideoInfo.ChromaFormatText));
//Trace(string.Format("-debug- video format: {0} is {1}",
// this.VideoInfo.Format, this.VideoInfo.FormatText));
//CountVideoFrames();// slows down the routine
// Trace(string.Format("-debug- video frames: {0}", this.VideoInfo.Frames));
}
return true;
}
// remove this and use TimeSpan
string SecondsToHMS(double duration)
{
int hours = (int)(duration / 3600);
int mins = (int)((duration / 60) - (hours * 60));
double seconds = duration - 60 * mins - 3600 * hours;
if (hours != 0)
{
return string.Format("{0:n0}h {1:n0}m {2:n2}s", hours, mins, seconds);
}
if (mins != 0)
{
return string.Format("{0:n0}m {1:n2}s", mins, seconds);
}
return string.Format("{0:n2}s", seconds);
}
void CountVideoFrames() // slow, find a better way of doing this
{
byte[] buffer = new byte[4];
_br.BaseStream.Seek(0, SeekOrigin.Begin);
int read = 0;
while ((read = _br.Read(buffer, 0, 4)) != 0)
{
if (buffer[0] == 0x00
&& buffer[1] == 0x00
&& buffer[2] == 0x01
&& buffer[3] == 0x00)
{
this.VideoInfo.Frames++;
}
}
}
void CountVideoGopHeaders() // slow, find a better way of doing this
{
byte[] buffer = new byte[4];
_br.BaseStream.Seek(0, SeekOrigin.Begin);
int read = 0;
while ((read = _br.Read(buffer, 0, 4)) != 0)
{
if (buffer[0] == 0x00
&& buffer[1] == 0x00
&& buffer[2] == 0x01
&& buffer[3] == 0xB8)
{
this.VideoInfo.GopHeaders++;
}
}
}
void ParseExtension(int offset)
{
offset += 4;
switch (GetByte(offset) >> 4)
{
case 1: ParseSequenceExt(offset);
break;
case 2:
ParseSequenceDisplayExt(offset);
break;
default:
break;
}
}
void ParseSequenceExt(int offset)
{
_mpegVersion = 2;
this.VideoInfo.Version = 2;
this.VideoInfo.ChromaFormat = (GetByte(offset + 1) & 0x06) >> 1;
}
void ParseSequenceDisplayExt(int offset)
{
this.VideoInfo.Format = (GetByte(offset) & 0x0E) >> 1;
}
int SkipPacketHeader(int offset)
{
byte mark = new byte();
if (_mpegVersion == 1)
{
offset += 6;
mark = GetByte(offset);
while (Convert.ToBoolean(mark & 0x80))
{
mark = GetByte(++offset);
}
if ((mark & 0xC0) == 0x40)
{
offset += 2;
}
mark = GetByte(offset);
if ((mark & 0xF0) == 0x20) { offset += 5; }
else if ((mark & 0xF0) == 0x30) { offset += 10; }
else offset++;
return offset;
}
else if (_mpegVersion == 2)
{
return (offset + 9 + GetByte(offset + 8));
}
else return (offset + 10);
}
void Trace(string msg)
{
if (this.EnableTrace)
{
Console.WriteLine(msg);
}
}
} octavia 0 Light Poster
Thanks a lot Diamonddrake :)
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