public MatroskaFile(string path)
{
this._path = path;
this._stream = new FastFileStream(path);
// read header
Element headerElement = this.ReadElement();
if (headerElement != null && headerElement.Id == ElementId.Ebml)
{
// read segment
this._stream.Seek(headerElement.DataSize, SeekOrigin.Current);
this._segmentElement = this.ReadElement();
if (this._segmentElement != null && this._segmentElement.Id == ElementId.Segment)
{
this._valid = true; // matroska file must start with ebml header and segment
}
}
}
/// <summary>
/// The read subtitle block.
/// </summary>
/// <param name="blockElement">
/// The block element.
/// </param>
/// <param name="clusterTimeCode">
/// The cluster time code.
/// </param>
/// <returns>
/// The <see cref="MatroskaSubtitle"/>.
/// </returns>
private MatroskaSubtitle ReadSubtitleBlock(Element blockElement, long clusterTimeCode)
{
int trackNumber = (int)this.ReadVariableLengthUInt();
if (trackNumber != this._subtitleRipTrackNumber)
{
this._stream.Seek(blockElement.EndPosition, SeekOrigin.Begin);
return null;
}
short timeCode = this.ReadInt16();
// lacing
byte flags = (byte)this._stream.ReadByte();
int frames;
switch (flags & 6)
{
case 0: // 00000000 = No lacing
Debug.Print("No lacing");
break;
case 2: // 00000010 = Xiph lacing
frames = this._stream.ReadByte() + 1;
Debug.Print("Xiph lacing ({0} frames)", frames);
break;
case 4: // 00000100 = Fixed-size lacing
frames = this._stream.ReadByte() + 1;
for (int i = 0; i < frames; i++)
{
this._stream.ReadByte(); // frames
}
Debug.Print("Fixed-size lacing ({0} frames)", frames);
break;
case 6: // 00000110 = EMBL lacing
frames = this._stream.ReadByte() + 1;
Debug.Print("EBML lacing ({0} frames)", frames);
break;
}
// save subtitle data
int dataLength = (int)(blockElement.EndPosition - this._stream.Position);
byte[] data = new byte[dataLength];
this._stream.Read(data, 0, dataLength);
return new MatroskaSubtitle(data, clusterTimeCode + timeCode);
}
/// <summary>
/// The read block group element.
/// </summary>
/// <param name="clusterElement">
/// The cluster element.
/// </param>
/// <param name="clusterTimeCode">
/// The cluster time code.
/// </param>
private void ReadBlockGroupElement(Element clusterElement, long clusterTimeCode)
{
MatroskaSubtitle subtitle = null;
Element element;
while (this._stream.Position < clusterElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.Block:
subtitle = this.ReadSubtitleBlock(element, clusterTimeCode);
if (subtitle == null)
{
return;
}
this._subtitleRip.Add(subtitle);
break;
case ElementId.BlockDuration:
long duration = (long)this.ReadUInt((int)element.DataSize);
if (subtitle != null)
{
subtitle.Duration = duration;
}
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
}
/// <summary>
/// The read cluster.
/// </summary>
/// <param name="clusterElement">
/// The cluster element.
/// </param>
private void ReadCluster(Element clusterElement)
{
long clusterTimeCode = 0;
Element element;
while (this._stream.Position < clusterElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.Timecode:
clusterTimeCode = (long)this.ReadUInt((int)element.DataSize);
break;
case ElementId.BlockGroup:
this.ReadBlockGroupElement(element, clusterTimeCode);
break;
case ElementId.SimpleBlock:
MatroskaSubtitle subtitle = this.ReadSubtitleBlock(element, clusterTimeCode);
if (subtitle != null)
{
this._subtitleRip.Add(subtitle);
}
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
}
/// <summary>
/// The read tracks element.
/// </summary>
/// <param name="tracksElement">
/// The tracks element.
/// </param>
private void ReadTracksElement(Element tracksElement)
{
this._tracks = new List<MatroskaTrackInfo>();
Element element;
while (this._stream.Position < tracksElement.EndPosition && (element = this.ReadElement()) != null)
{
if (element.Id == ElementId.TrackEntry)
{
this.ReadTrackEntryElement(element);
}
else
{
this._stream.Seek(element.DataSize, SeekOrigin.Current);
}
}
}
/// <summary>
/// The read info element.
/// </summary>
/// <param name="infoElement">
/// The info element.
/// </param>
private void ReadInfoElement(Element infoElement)
{
Element element;
while (this._stream.Position < infoElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.TimecodeScale:
// Timestamp scale in nanoseconds (1.000.000 means all timestamps in the segment are expressed in milliseconds)
this._timecodeScale = (int)this.ReadUInt((int)element.DataSize);
break;
case ElementId.Duration:
// Duration of the segment (based on TimecodeScale)
this._duration = element.DataSize == 4 ? this.ReadFloat32() : this.ReadFloat64();
this._duration /= this._timecodeScale * 1000000.0;
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
}
/// <summary>
/// The read content encoding element.
/// </summary>
/// <param name="contentEncodingElement">
/// The content encoding element.
/// </param>
/// <param name="contentCompressionAlgorithm">
/// The content compression algorithm.
/// </param>
/// <param name="contentEncodingType">
/// The content encoding type.
/// </param>
private void ReadContentEncodingElement(Element contentEncodingElement, ref int contentCompressionAlgorithm, ref int contentEncodingType)
{
Element element;
while (this._stream.Position < contentEncodingElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.ContentEncodingOrder:
ulong contentEncodingOrder = this.ReadUInt((int)element.DataSize);
Debug.WriteLine("ContentEncodingOrder: " + contentEncodingOrder);
break;
case ElementId.ContentEncodingScope:
ulong contentEncodingScope = this.ReadUInt((int)element.DataSize);
Debug.WriteLine("ContentEncodingScope: " + contentEncodingScope);
break;
case ElementId.ContentEncodingType:
contentEncodingType = (int)this.ReadUInt((int)element.DataSize);
break;
case ElementId.ContentCompression:
Element compElement;
while (this._stream.Position < element.EndPosition && (compElement = this.ReadElement()) != null)
{
switch (compElement.Id)
{
case ElementId.ContentCompAlgo:
contentCompressionAlgorithm = (int)this.ReadUInt((int)compElement.DataSize);
break;
case ElementId.ContentCompSettings:
ulong contentCompSettings = this.ReadUInt((int)compElement.DataSize);
Debug.WriteLine("ContentCompSettings: " + contentCompSettings);
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
}
/// <summary>
/// The read track entry element.
/// </summary>
/// <param name="trackEntryElement">
/// The track entry element.
/// </param>
private void ReadTrackEntryElement(Element trackEntryElement)
{
long defaultDuration = 0;
bool isVideo = false;
bool isAudio = false;
bool isSubtitle = false;
int trackNumber = 0;
string name = string.Empty;
string language = string.Empty;
string codecId = string.Empty;
string codecPrivate = string.Empty;
// var biCompression = string.Empty;
int contentCompressionAlgorithm = -1;
int contentEncodingType = -1;
Element element;
while (this._stream.Position < trackEntryElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.DefaultDuration:
defaultDuration = (int)this.ReadUInt((int)element.DataSize);
break;
case ElementId.Video:
this.ReadVideoElement(element);
isVideo = true;
break;
case ElementId.Audio:
isAudio = true;
break;
case ElementId.TrackNumber:
trackNumber = (int)this.ReadUInt((int)element.DataSize);
break;
case ElementId.Name:
name = this.ReadString((int)element.DataSize, Encoding.UTF8);
break;
case ElementId.Language:
language = this.ReadString((int)element.DataSize, Encoding.ASCII);
break;
case ElementId.CodecId:
codecId = this.ReadString((int)element.DataSize, Encoding.ASCII);
break;
case ElementId.TrackType:
switch (this._stream.ReadByte())
{
case 1:
isVideo = true;
break;
case 2:
isAudio = true;
break;
case 17:
isSubtitle = true;
break;
}
break;
case ElementId.CodecPrivate:
codecPrivate = this.ReadString((int)element.DataSize, Encoding.UTF8);
// if (codecPrivate.Length > 20)
// biCompression = codecPrivate.Substring(16, 4);
break;
case ElementId.ContentEncodings:
contentCompressionAlgorithm = 0; // default value
contentEncodingType = 0; // default value
Element contentEncodingElement = this.ReadElement();
if (contentEncodingElement != null && contentEncodingElement.Id == ElementId.ContentEncoding)
{
this.ReadContentEncodingElement(element, ref contentCompressionAlgorithm, ref contentEncodingType);
}
break;
}
this._stream.Seek(element.EndPosition, SeekOrigin.Begin);
}
this._tracks.Add(new MatroskaTrackInfo { TrackNumber = trackNumber, IsVideo = isVideo, IsAudio = isAudio, IsSubtitle = isSubtitle, Language = language, CodecId = codecId, CodecPrivate = codecPrivate, Name = name, ContentEncodingType = contentEncodingType, ContentCompressionAlgorithm = contentCompressionAlgorithm });
if (isVideo)
{
if (defaultDuration > 0)
{
this._frameRate = 1.0 / (defaultDuration / 1000000000.0);
}
this._videoCodecId = codecId;
}
}
/// <summary>
/// The read video element.
/// </summary>
/// <param name="videoElement">
/// The video element.
/// </param>
private void ReadVideoElement(Element videoElement)
{
Element element;
while (this._stream.Position < videoElement.EndPosition && (element = this.ReadElement()) != null)
{
switch (element.Id)
{
case ElementId.PixelWidth:
this._pixelWidth = (int)this.ReadUInt((int)element.DataSize);
break;
case ElementId.PixelHeight:
this._pixelHeight = (int)this.ReadUInt((int)element.DataSize);
break;
default:
this._stream.Seek(element.DataSize, SeekOrigin.Current);
break;
}
}
}
/// <summary>
/// The find track start in cluster.
/// </summary>
/// <param name="cluster">
/// The cluster.
/// </param>
/// <param name="targetTrackNumber">
/// The target track number.
/// </param>
/// <returns>
/// The <see cref="long"/>.
/// </returns>
private long FindTrackStartInCluster(Element cluster, int targetTrackNumber)
{
long clusterTimeCode = 0L;
long trackStartTime = -1L;
bool done = false;
Element element;
while (this._stream.Position < cluster.EndPosition && (element = this.ReadElement()) != null && !done)
{
switch (element.Id)
{
case ElementId.None:
done = true;
break;
case ElementId.Timecode:
// Absolute timestamp of the cluster (based on TimecodeScale)
clusterTimeCode = (long)this.ReadUInt((int)element.DataSize);
break;
case ElementId.BlockGroup:
this.ReadBlockGroupElement(element, clusterTimeCode);
break;
case ElementId.SimpleBlock:
int trackNumber = (int)this.ReadVariableLengthUInt();
if (trackNumber == targetTrackNumber)
{
// Timecode (relative to Cluster timecode, signed int16)
trackStartTime = this.ReadInt16();
done = true;
}
break;
}
this._stream.Seek(element.EndPosition, SeekOrigin.Begin);
}
return (clusterTimeCode + trackStartTime) * this._timecodeScale / 1000000;
}
