public Media.Container.Node ReadUnit(TransportStreamUnit.PacketIdentifier name, long offset = 0)
{
long positionStart = Position;
Media.Container.Node result = ReadUnits(offset, Length - offset, name).FirstOrDefault();
Position = positionStart;
return(result);
}
public static string ToTextualConvention(TransportStreamReader reader, byte[] identifier)
{
TransportStreamUnit.PacketIdentifier result = TransportStreamUnit.GetPacketIdentifier(identifier, reader.UnitOverhead);
if (TransportStreamUnit.IsReserved(result))
{
return("Reserved");
}
if (TransportStreamUnit.IsDVBMetaData(result))
{
return("DVBMetaData");
}
if (TransportStreamUnit.IsUserDefined(result))
{
return("UserDefined");
}
return(result.ToString());
}
internal protected virtual void ParseDescriptionTable(Container.Node node)
{
int offset = ReadPointerField(node);
//Get the table id
TransportStreamUnit.TableIdentifier tableId = (TransportStreamUnit.TableIdentifier)node.Data[offset++];
if (tableId != TransportStreamUnit.TableIdentifier.ProgramAssociation)
{
return;
}
TransportStreamUnit.PacketIdentifier pcrPid = (TransportStreamUnit.PacketIdentifier)(Common.Binary.ReadU16(node.Data, offset, Common.Binary.IsLittleEndian) & TransportStreamUnit.PacketIdentifierMask);
int infoLength = Common.Binary.ReadU16(node.Data, ref offset, Common.Binary.IsLittleEndian) & 0x0FFF;
//Determine where to end (don't count the crc)
int end = (infoLength + 3) - 4;
while (offset < end)
{
byte esType = node.Data[offset++];
//Could store two bytes and have methods to extract with masks.
TransportStreamUnit.PacketIdentifier esPid = (TransportStreamUnit.PacketIdentifier)(Common.Binary.ReadU16(node.Data, offset, Common.Binary.IsLittleEndian) & TransportStreamUnit.PacketIdentifierMask);
ushort descLength = (ushort)(Common.Binary.ReadU16(node.Data, offset, Common.Binary.IsLittleEndian) & 0x0FFF);
var entry = new Tuple <TransportStreamUnit.PacketIdentifier, ushort>(esPid, descLength);
m_ProgramDescriptions.AddOrUpdate(esType, entry, (a, old) => entry);
offset += 2;
}
//CRC
}
//Static and take reader?
//Maps from Program to PacketIdentifer?
internal protected virtual void ParseProgramAssociationTable(Container.Node node)
{
int offset = ReadPointerField(node);
//Get the table id
TransportStreamUnit.TableIdentifier tableId = (TransportStreamUnit.TableIdentifier)node.Data[offset++];
if (tableId != TransportStreamUnit.TableIdentifier.ProgramAssociation)
{
return;
}
/*
* Program Association Table (PAT) section syntax
* syntax bit index # of bits mnemonic
* table_id 0 8 uimsbf
* section_syntax_indicator 8 1 bslbf
* '0' 9 1 bslbf
* reserved 10 2 bslbf
* section_length 12 12 uimsbf
* transport_stream_id 24 16 uimsbf
* reserved 40 2 bslbf
* version_number 42 5 uimsbf
* current_next_indicator 47 1 bslbf
* section_number 48 8 bslbf
* last_section_number 56 8 bslbf
* for i = 0 to N
* program_number 56 + (i * 4) 16 uimsbf
* reserved 72 + (i * 4) 3 bslbf
* if program_number = 0
* network_PID 75 + (i * 4) 13 uimsbf
* else
* program_map_pid 75 + (i * 4) 13 uimsbf
* end if
* next
* CRC_32 88 + (i * 4) 32 rpchof
* Table section legend
*/
//section syntax indicator, 0 bit, and 2 reserved bits.
//Section Length The number of bytes that follow for the syntax section (with CRC value) and/or table data. These bytes must not exceed a value of 1021.
// section_length field is a 12-bit field that gives the length of the table section beyond this field
//Since it is carried starting at bit index 12 in the section (the second and third bytes), the actual size of the table section is section_length + 3.
ushort sectionLength = (ushort)(Common.Binary.ReadU16(node.Data, ref offset, Common.Binary.IsLittleEndian) & 0x0FFF);
//transport_stream_id 24 16 uimsbf
ushort transportStreamId = (ushort)(Common.Binary.ReadU16(node.Data, ref offset, Common.Binary.IsLittleEndian) & 0x0FFF);
//Skip reserved, version number and current/next indicator.
++offset;
//Skip section number
++offset;
//Skip last section number
++offset;
//Determine where to end (don't count the crc)
int end = (sectionLength + 3) - 4;
//4 bytes per ProgramInfo in node.Data
while (offset < end)
{
//2 Bytes ProgramNumber
ushort programNumber = Common.Binary.ReadU16(node.Data, offset, Common.Binary.IsLittleEndian);
//3 bits reserved
//2 Bytes ProgramID
TransportStreamUnit.PacketIdentifier pid = TransportStreamUnit.GetPacketIdentifier(node.Data, offset + 2);
//Add or update the entry
m_ProgramAssociations.AddOrUpdate(programNumber, pid, (id, old) => pid);
//Move the offset
offset += 4;
}
//CRC
}
/// <summary>
/// Enumerates each unit found in the TransportStream.
/// When a unit is found it is either added to the Streams or it is parsed to obtain information.
/// </summary>
/// <returns></returns>
public override IEnumerator <Container.Node> GetEnumerator()
{
//Ensure a Unit remains
while (Remaining >= TransportUnitSize)
{
//Read a unit
Container.Node next = ReadNext();
//No more units stops the enumeration
if (next == null)
{
yield break;
}
//Return the unit for external handling
yield return(next);
//Get the type of packet this is
TransportStreamUnit.PacketIdentifier pid = GetPacketIdentifier(this, next.Identifier);
//Need to parse the packet to ensure that GetTracks can always be updated.
switch (pid)
{
case TransportStreamUnit.PacketIdentifier.ProgramAssociationTable:
{
/*
*
* The Program Association Table (PAT) is the entry point for the Program Specific Information (PSI) tables.
*
* It is always carried in packets with PID (packet ID) = 0. For each assigned program number, the PAT lists the PID for packets containing that program's PMT.
*
* The PMT lists all the PIDs for packets containing elements of a particular program (audio, video, aux data, and Program Clock Reference (PCR)).
*
* The PAT also contains the PIDs for the NIT(s).
*
* The NIT is an optional table that maps channel frequencies, transponder numbers, and other guide information for programs.
*
*/
ParseProgramAssociationTable(next);
goto default;
}
case TransportStreamUnit.PacketIdentifier.DescriptionTable: // TableIdentifier.ProgramMap
{
//Parse the table
ParseDescriptionTable(next);
goto default;
}
//case PacketIdentifier.Program
case TransportStreamUnit.PacketIdentifier.ConditionalAccessTable:
case TransportStreamUnit.PacketIdentifier.SelectionInformationTable:
case TransportStreamUnit.PacketIdentifier.NetworkInformationTable:
{
//Todo
goto default;
}
default:
{
//Include the PId with the StreamId
m_ProgramIds.Add(pid);
break;
}
}
//Done with the unit
Skip(next.DataSize);
}
}
