MPEG2_VES_EssenceSubParser Class Reference

Class that handles parsing of MPEG-2 video elementary streams. More...

#include <esp_mpeg2ves.h>

Inheritance diagram for MPEG2_VES_EssenceSubParser:

List of all members.

Public Member Functions
	MPEG2_VES_EssenceSubParser ()
virtual EssenceSubParserPtr	NewParser (void) const
	Build a new parser of this type and return a pointer to it.
virtual StringList	HandledExtensions (void)
	Report the extensions of files this sub-parser is likely to handle.
virtual EssenceStreamDescriptorList	IdentifyEssence (FileHandle InFile)
	Examine the open file and return a list of essence descriptors.
virtual WrappingOptionList	IdentifyWrappingOptions (FileHandle InFile, EssenceStreamDescriptor &Descriptor)
	Examine the open file and return the wrapping options known by this parser.
virtual void	Use (UInt32 Stream, WrappingOptionPtr &UseWrapping)
	Set a wrapping option for future Read and Write calls.
virtual bool	SetEditRate (Rational EditRate)
	Set a non-native edit rate.
virtual Rational	GetEditRate (void)
	Get the current edit rate.
virtual Position	GetCurrentPosition (void)
	Get the current position in SetEditRate() sized edit units.
virtual void	SetIndexManager (IndexManagerPtr &TheManager, int StreamID=0)
	Set the IndexManager for this essence stream (and the stream ID if we are not the main stream).
virtual DataChunkPtr	Read (FileHandle InFile, UInt32 Stream, UInt64 Count=1)
	Read a number of wrapping items from the specified stream and return them in a data chunk.
virtual EssenceSourcePtr	GetEssenceSource (FileHandle InFile, UInt32 Stream, UInt64 Count=1)
	Build an EssenceSource to read a number of wrapping items from the specified stream.
virtual Length	Write (FileHandle InFile, UInt32 Stream, MXFFilePtr OutFile, UInt64 Count=1)
	Write a number of wrapping items from the specified stream to an MXF file.
virtual bool	SetOption (std::string Option, Int64 Param=0)
	Set a parser specific option.
virtual std::string	GetParserName (void) const
	Get a unique name for this sub-parser.
Protected Member Functions
MDObjectPtr	BuildMPEG2VideoDescriptor (FileHandle InFile, UInt64 Start=0)
	Read the sequence header at the specified position in an MPEG2 file to build an essence descriptor.
size_t	ReadInternal (FileHandle InFile, UInt32 Stream, UInt64 Count)
	Scan the essence to calculate how many bytes to transfer for the given edit unit count.
int	BuffGetU8 (FileHandle InFile)
	Get a byte from the current stream.
Protected Attributes
Rational	NativeEditRate
	The native edit rate of this essence.
Rational	SelectedEditRate
	Selected edit rate of this essence.
unsigned int	EditRatio
	Ratio of selected to native edit rate.
Position	PictureNumber
	Current picture number.
Position	AnchorFrame
	Picture number of last "anchor frame".
size_t	CachedDataSize
	The size of the next data to be read, or (size_t)-1 if not known.
UInt64	CachedCount
	The number of wrapping units that CachedDataSize relates to.
Position	CurrentPos
	Current position in the input file.
int	GOPOffset
	The stream position of this picture in the GOP.
bool	ClosedGOP
	True if the current GOP is flagged as closed.
UInt8	Buffer [MPEG2_VES_BUFFERSIZE]
	Buffer for efficient file reading.
int	BuffCount
	Count of bytes still unread in Buffer.
UInt8 *	BuffPtr
	Pointer to next byte to read from Buffer.
bool	EditPoint
	Set true each time an edit point (sequence header of a closed GOP) and false for other frames.
bool	SelectiveIndex
	True if each index entry is stored and only added to index by a call to SetOption("AddIndexEntry");.
bool	EndOfStream
	True once the end of the stream has been read.
MDObjectParent	CurrentDescriptor
	Pointer to the last essence descriptor we built.
Friends
class	MPEG2_VES_EssenceSubParser::ESP_EssenceSource
Classes
class	ESP_EssenceSource
	Class for EssenceSource objects for parsing/sourcing MPEG-VES essence. More...

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Detailed Description

Class that handles parsing of MPEG-2 video elementary streams.

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Constructor & Destructor Documentation

MPEG2_VES_EssenceSubParser

(

)

[inline]

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Member Function Documentation

virtual EssenceSubParserPtr NewParser

(

void

)

const [inline, virtual]

Build a new parser of this type and return a pointer to it.

Implements EssenceSubParser.

StringList HandledExtensions

(

void

)

[virtual]

Report the extensions of files this sub-parser is likely to handle.

Reimplemented from EssenceSubParser.

EssenceStreamDescriptorList IdentifyEssence

(

FileHandle

InFile

)

[virtual]

Examine the open file and return a list of essence descriptors.

Note:

Valid MPEG2-VES files with > 510 extra zeroes before the first start code will not be identifed!

< Start position of sequence header (when found)

< Number of bytes left in buffer to scan

Reimplemented from EssenceSubParser.

WrappingOptionList IdentifyWrappingOptions	(	FileHandle	InFile,
		EssenceStreamDescriptor &	Descriptor
	)			[virtual]

Examine the open file and return the wrapping options known by this parser.

Parameters:

	InFile	The open file to examine (if the descriptor does not contain enough info)
	Descriptor	An essence stream descriptor (as produced by function IdentifyEssence) of the essence stream requiring wrapping

Note:

The options should be returned in an order of preference as the caller is likely to use the first that it can support

Reimplemented from EssenceSubParser.

void Use	(	UInt32	Stream,
		WrappingOptionPtr &	UseWrapping
	)			[virtual]

Set a wrapping option for future Read and Write calls.

Reimplemented from EssenceSubParser.

bool SetEditRate

(

Rational

EditRate

)

[virtual]

Set a non-native edit rate.

Returns:

true if this rate is acceptable

Reimplemented from EssenceSubParser.

virtual Rational GetEditRate

(

void

)

[inline, virtual]

Get the current edit rate.

Implements EssenceSubParser.

Position GetCurrentPosition

(

void

)

[virtual]

Get the current position in SetEditRate() sized edit units.

Returns:

0 if position not known

Implements EssenceSubParser.

virtual void SetIndexManager	(	IndexManagerPtr &	TheManager,
		int	StreamID = 0
	)			[inline, virtual]

Set the IndexManager for this essence stream (and the stream ID if we are not the main stream).

Also force reordering to be used

Reimplemented from EssenceSubParser.

DataChunkPtr Read	(	FileHandle	InFile,
		UInt32	Stream,
		UInt64	Count = 1
	)			[virtual]

Read a number of wrapping items from the specified stream and return them in a data chunk.

If frame or line mapping is used the parameter Count is used to determine how many items are read. In frame wrapping it is in units of EditRate, as specified in the call to Use(), which may not be the frame rate of this essence

Note:

This is going to take a lot of memory in clip wrapping!

Implements EssenceSubParser.

virtual EssenceSourcePtr GetEssenceSource	(	FileHandle	InFile,
		UInt32	Stream,
		UInt64	Count = 1
	)			[inline, virtual]

Build an EssenceSource to read a number of wrapping items from the specified stream.

Implements EssenceSubParser.

Length Write	(	FileHandle	InFile,
		UInt32	Stream,
		MXFFilePtr	OutFile,
		UInt64	Count = 1
	)			[virtual]

Write a number of wrapping items from the specified stream to an MXF file.

If frame or line mapping is used the parameter Count is used to determine how many items are read. In frame wrapping it is in units of EditRate, as specified in the call to Use(), which may not be the frame rate of this essence stream

Note:

This is the only safe option for clip wrapping

Returns:

Count of bytes transferred

Implements EssenceSubParser.

bool SetOption	(	std::string	Option,
		Int64	Param = 0
	)			[virtual]

Set a parser specific option.

Returns:

true if the option was successfully set

Reimplemented from EssenceSubParser.

virtual std::string GetParserName

(

void

)

const [inline, virtual]

Get a unique name for this sub-parser.

The name must be all lower case, and must be unique. The recommended name is the part of the filename of the parser header after "esp_" and before the ".h". If the parser has no name return "" (however this will prevent named wrapping option selection for this sub-parser)

Reimplemented from EssenceSubParser.

MDObjectPtr BuildMPEG2VideoDescriptor	(	FileHandle	InFile,
		UInt64	Start = 0
	)			[protected]

Read the sequence header at the specified position in an MPEG2 file to build an essence descriptor.

DRAGONS: Currently rather scrappy

size_t ReadInternal	(	FileHandle	InFile,
		UInt32	Stream,
		UInt64	Count
	)			[protected]

Scan the essence to calculate how many bytes to transfer for the given edit unit count.

Note:

The file position pointer is moved to the start of the chunk at the end of this function, but CurrentPos points to the start of the next edit unit

PictureNumber is incremented for each picture found

Set true once the start of a picture has been found

int BuffGetU8

(

FileHandle

InFile

)

[protected]

Get a byte from the current stream.

Returns:

-1 if end of file

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Friends And Related Function Documentation

friend class MPEG2_VES_EssenceSubParser::ESP_EssenceSource [friend]

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Member Data Documentation

Rational NativeEditRate [protected]

The native edit rate of this essence.

Rational SelectedEditRate [protected]

Selected edit rate of this essence.

unsigned int EditRatio [protected]

Ratio of selected to native edit rate.

Position PictureNumber [protected]

Current picture number.

Position AnchorFrame [protected]

Picture number of last "anchor frame".

size_t CachedDataSize [protected]

The size of the next data to be read, or (size_t)-1 if not known.

UInt64 CachedCount [protected]

The number of wrapping units that CachedDataSize relates to.

Position CurrentPos [protected]

Current position in the input file.

Note:

Other functions may move the file pointer between calls to our functions

int GOPOffset [protected]

The stream position of this picture in the GOP.

The first picture in the GOP is picture 0

bool ClosedGOP [protected]

True if the current GOP is flagged as closed.

UInt8 Buffer[MPEG2_VES_BUFFERSIZE] [protected]

Buffer for efficient file reading.

int BuffCount [protected]

Count of bytes still unread in Buffer.

UInt8* BuffPtr [protected]

Pointer to next byte to read from Buffer.

bool EditPoint [protected]

Set true each time an edit point (sequence header of a closed GOP) and false for other frames.

Note:

This flag can be checked by calling SetOption("EditPoint") which will return the flag. The flag tells only if the last frame is the start of a new sequence.

bool SelectiveIndex [protected]

True if each index entry is stored and only added to index by a call to SetOption("AddIndexEntry");.

bool EndOfStream [protected]

True once the end of the stream has been read.

MDObjectParent CurrentDescriptor [protected]

Pointer to the last essence descriptor we built.

This is used as a quick-and-dirty check that we know how to process this source

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The documentation for this class was generated from the following files:

• esp_mpeg2ves.h
• esp_mpeg2ves.cpp

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