ts::TSPacketQueue Class Reference

Transport stream packet queue for inter-thread communication. More...

#include <tsTSPacketQueue.h>

Public Member Functions
	TSPacketQueue (size_t size=DEFAULT_SIZE)
	Default constructor.
size_t	bufferSize () const
	Get the size of the buffer in packets.
size_t	currentSize () const
	Get the current number of packets in the buffer.
bool	eof () const
	Check if the writer thread has reported an end of file condition.
bool	getPacket (TSPacket &packet, TSPacketMetadata *mdata, BitRate &bitrate)
	Called by the reader thread to get the next packet without waiting.
bool	lockWriteBuffer (TSPacket *&buffer, TSPacketMetadata *&mdata, size_t &buffer_size, size_t min_size=1)
	Called by the writer thread to get a write buffer.
void	releaseWriteBuffer (size_t count)
	Called by the writer thread to release the write buffer.
void	reset (size_t size=NPOS)
	Reset and resize the buffer.
void	setBitrate (const BitRate &bitrate)
	Called by the writer thread to report the input bitrate.
void	setEOF ()
	Called by the writer thread to report the end of input thread.
void	stop ()
	Called by the reader thread to tell the writer thread to stop immediately.
bool	stopped () const
	Check if the reader thread has reported a stop condition.
bool	waitPackets (TSPacket *buffer, TSPacketMetadata *mdata, size_t buffer_count, size_t &actual_count, BitRate &bitrate)
	Called by the reader thread to wait for packets.

Static Public Attributes
static constexpr size_t	DEFAULT_SIZE = 1000
	Default size in packets of the buffer.

Detailed Description

Transport stream packet queue for inter-thread communication.

A writer thread produces packets. The input packets are directly written into the buffer. The writer thread invokes lockWriteBuffer() to get a write window inside the buffer. When packets have been written into this buffer, the writer thread calls releaseWriteBuffer().

A reader thread consumes packets. The packets are consumed one by one and copied out of the buffer using getPacket().

The input bitrate, if known, is transmitted to the reader thread. If the writer thread is aware of the exact bitrate, it calls setBitrate() and the specified value is returned to the reader thread. If the input bitrate is unknown, the buffer automatically computes it based on PCR's.

Termination conditions can be triggered on both sides.

Constructor & Destructor Documentation

TSPacketQueue()

ts::TSPacketQueue::TSPacketQueue

(

size_t

size = DEFAULT_SIZE

)

Default constructor.

Parameters

[in]

size

Size of the buffer in packets.

Member Function Documentation

reset()

void ts::TSPacketQueue::reset

(

size_t

size = NPOS

)

Reset and resize the buffer.

It is illegal to reset the buffer while the writer thread has locked the buffer. This is not enforced by this class. It is the responsibility of the application to check this.

Parameters

[in]

size

New size of the buffer in packets. By default, when set to NPOS, reset the queue without resizing the buffer.

bufferSize()

size_t ts::TSPacketQueue::bufferSize

(

)

const

Get the size of the buffer in packets.

Returns

The size of the buffer in packets.

currentSize()

size_t ts::TSPacketQueue::currentSize

(

)

const

Get the current number of packets in the buffer.

Returns

The current number of packets in the buffer.

lockWriteBuffer()

bool ts::TSPacketQueue::lockWriteBuffer	(	TSPacket *&	buffer,
		TSPacketMetadata *&	mdata,
		size_t &	buffer_size,
		size_t	min_size = 1
	)

Called by the writer thread to get a write buffer.

The writer thread is suspended until enough free space is made in the buffer or the reader thread triggers a stop condition.

Parameters

[out]	buffer	Address of the packet write buffer.
[out]	mdata	Address of the packet metadata write buffer.
[out]	buffer_size	Size in packets of the write buffer.
[in]	min_size	Minimum number of free packets to get. This is just a hint. The returned size can be smaller, for instance when the write window of the circular buffer is close to the end of the buffer.

Returns

True when the write buffer is correctly available. False when the reader thread has signalled a stop condition.

releaseWriteBuffer()

void ts::TSPacketQueue::releaseWriteBuffer

(

size_t

count

)

Called by the writer thread to release the write buffer.

The packets were written by the writer thread at the address which was returned by lockWriteBuffer().

Parameters

[in]

count

Number of packets which were written in the buffer. Must be no greater than the size which was returned by lockWriteBuffer().

setBitrate()

void ts::TSPacketQueue::setBitrate

(

const BitRate &

bitrate

)

Called by the writer thread to report the input bitrate.

Parameters

[in]

bitrate

Input bitrate. If zero, the input bitrate is unknown and will be computed from PCR's.

stopped()

bool ts::TSPacketQueue::stopped ( ) const

inline

Check if the reader thread has reported a stop condition.

Returns

True if the reader thread has reported a stop condition.

getPacket()

bool ts::TSPacketQueue::getPacket	(	TSPacket &	packet,
		TSPacketMetadata *	mdata,
		BitRate &	bitrate
	)

Called by the reader thread to get the next packet without waiting.

The reader thread is never suspended. If no packet is available, return false.

Parameters

[out]	packet	The returned packet. Unmodified when no packet is available.
[out]	mdata	The returned packet metadata, if not null. Unmodified when no packet is available.
[out]	bitrate	Input bitrate or zero if unknown.

Returns

True if a packet was returned in packet. False if none was available or an end of file occured.

waitPackets()

bool ts::TSPacketQueue::waitPackets	(	TSPacket *	buffer,
		TSPacketMetadata *	mdata,
		size_t	buffer_count,
		size_t &	actual_count,
		BitRate &	bitrate
	)

Called by the reader thread to wait for packets.

The reader thread is suspended until at least one packet is available.

Parameters

[out]	buffer	Address of packet buffer.
[out]	mdata	Address of the packet metadata buffer. Can be null.
[in]	buffer_count	Size of buffer in number of packets.
[out]	actual_count	Number of returned packets in buffer.
[out]	bitrate	Input bitrate or zero if unknown.

Returns

True if a packets were returned in buffer. False on error or end of file.

eof()

bool ts::TSPacketQueue::eof

(

)

const

Check if the writer thread has reported an end of file condition.

Returns

True if the writer thread has reported an end of file condition.

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

• tsTSPacketQueue.h