vrs::Record Class Reference

Essential VRS class holding a record's details and payload in memory during creation. More...

#include <Record.h>

Classes
struct	uninitialized_byte
	Public for testing. More...

Public Types
enum class	Type : uint8_t {   UNDEFINED = 0 , STATE = 1 , CONFIGURATION = 2 , DATA = 3 ,   TAGS = 4 , COUNT }

Public Member Functions
void	recycle ()
void	set (double timestamp, Type type, uint32_t formatVersion, const DataSource &data, uint64_t creationOrder)
void	addDirectWriteRecordData (std::unique_ptr< DirectWriteRecordData > &&directWriteRecordData)
	Add some data to write directly at the end of the record when it's written to disk.
bool	shouldTryToCompress () const
uint32_t	compressRecord (Compressor &compressor)
int	writeRecord (WriteFileHandler &file, StreamId streamId, uint32_t &inOutRecordSize, Compressor &compressor, uint32_t compressedSize)
double	getTimestamp () const
	Get the record's timestamp.
uint64_t	getCreationOrder () const
size_t	getSize () const
	Get the record's payload size, uncompressed.
Type	getRecordType () const
	Get the record's record type.

Static Public Member Functions
static const char *	typeName (Type type)
	Get a record type as a text string.

Static Public Attributes
static const double	kMaxTimestamp = numeric_limits<double>::max()
	Maximum timestamp for a record.

Friends
class	RecordManager

Detailed Description

Essential VRS class holding a record's details and payload in memory during creation.

Record are containers for data captured at a specific point in time (their timestamp).

Records can only be created using Recordable::createRecord(), and are then owned and managed by the recordable's private RecordManager.

There are 3 types of user records: configuration, state and data records.

Configuration records are meant to describe how the device (or virtual device, such as an algorithm), is configured: this could represent the resolution of a camera sensor, its framerate, its exposure setting if it's fixed, etc. Whenever the configuration of a device changes, a new configuration record should be generated. At the beginning of any recording, a configuration record is also expected, and VRS itself might call a Recordable's createConfigurationRecord() method to be sure a configuration record is created.

State records are meant to describe the internal state of the device or virtual device. A camera might be configured in auto-exposure mode, so that the exposure of the camera might evolve over time, based on the images recorded. Similarly, algorithms, in particular vision algorithms, may have an internal state, and it might be useful to record that state. However, we do not necessarily want to record every state change. The internal exposure of a camera might change at every frame, and the potentially very large internal state of a vision algorithm is also likely to change each time a sensor record is processed. Devices with changing internal state are expected to generate state records, as necessary, but at a controlled rate, so as to allow to reproduce replay conditions without generating an overwhelming amount of data. Similarly to configuration records, State records might be requested by VRS, by calling a Recordable's createStateRecord method.

Data records are used to capture the actual sensor data. Devices are expected to create Data records whenever data is received from some kind of device driver, or arbitrarily in the case of synthetic data.

Records and compressed Records have space for a RecordHeader allocated before their data, so records can be written in a single write operation.

See Recordable::createRecord() to see how to create records.

Member Enumeration Documentation

Type

enum class vrs::Record::Type : uint8_t

strong

Record type definitions. Only Configuration, State and Data records are used by the client users of the APIs. Tags records are internal to VRS, and will not be exposed in the RecordFileReader's index even when they are used internally.

Enumerator
UNDEFINED	don't use.
STATE	device or algorithm state information.
CONFIGURATION	device or algorithm configuration.
DATA	device or algorithm data.
TAGS	tags record (VRS internal type).
COUNT	Count of enum values.

Member Function Documentation

compressRecord()

uint32_t vrs::Record::compressRecord

(

Compressor &

compressor

)

Try to compress the record.

Returns

The compressed size, or 0 if the compression did not work.

recycle()

void vrs::Record::recycle

(

)

When VRS is done using a record, it recycles it, rather than delete it.

set()

void vrs::Record::set	(	double	timestamp,
		Type	type,
		uint32_t	formatVersion,
		const DataSource &	data,
		uint64_t	creationOrder
	)

Copy data into the record, so that we can write it to disk later if we needed.

shouldTryToCompress()

bool vrs::Record::shouldTryToCompress

(

)

const

Tell if an attempt should be made to compress the record. If compression can't reduce the size of the record, then the record is written uncompressed.

writeRecord()

int vrs::Record::writeRecord	(	WriteFileHandler &	file,
		StreamId	streamId,
		uint32_t &	inOutRecordSize,
		Compressor &	compressor,
		uint32_t	compressedSize
	)

Write a possibly compressed record to a file (header + data).

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

• vrs/Record.h
• vrs/Record.cpp