AVState Class Reference

#include <video.h>

Public Types
using	OnClearFrameQueueFunction = std::function< void()>

Public Member Functions
	AVState (Video &video)
	~AVState ()
void	init (int stream, AVCodec *codec, AVCodecContext *codecContext)
void	close ()
bool	isValid () const
int	getStream () const
void	startDecodeThread (const OnClearFrameQueueFunction &onClearFrameQueueFunction=OnClearFrameQueueFunction())
void	exitDecodeThread (bool join)
bool	isFinished () const
void	clearFrameQueue ()
void	clearPacketQueue ()
bool	matchesStream (const AVPacket &packet) const
bool	addSeekStartPacket (const bool &exitIOThreadSignalled)
bool	addSeekEndPacket (const bool &exitIOThreadSignalled, double seekTargetSecs)
bool	addEndOfFilePacket (const bool &exitIOThreadSignalled)
bool	addIOFinishedPacket (const bool &exitIOThreadSignalled)
bool	addPacket (AVPacket &packet, const bool &exitIOThreadSignalled)
bool	waitForFrameQueueEmpty (bool &exitIOThreadSignalled)
void	cancelWaitForFrameQueueEmpty ()
void	resetWaitForFrameQueueEmpty ()
bool	waitForEndOfFileProcessed ()
void	cancelWaitForEndOfFileProcessed ()
void	resetEndOfFileProcessed ()
void	waitSeekStartPacketProcessed ()
int	waitForReceiveFrame ()
void	drainSeekFrameQueue ()
Frame	popFrame ()
Frame	tryPopFrame (double pts)
Frame	peekFrame ()
Frame	popSeekFrame ()
void	notifyStartIOThread ()
void	notifyExitIOThread ()
AVCodec &	getCodec ()
AVCodecContext &	getCodecContext ()

Description

Full state for either audio or video. Responsible for pulling packets from the packet queue and decoding them into frames.

Member Typedef Documentation

OnClearFrameQueueFunction

using OnClearFrameQueueFunction = std::function<void()>

Constructor & Destructor Documentation

AVState()

AVState

(

Video &

video

)

Constructor

Parameters

video

video to play

~AVState()

~AVState

(

)

Destructor

Member Function Documentation

addEndOfFilePacket()

bool addEndOfFilePacket

(

const bool &

exitIOThreadSignalled

)

Adds the 'end of file' packet to the packet queue. The end of file packet is a special packet with a nullptr for data.

addIOFinishedPacket()

bool addIOFinishedPacket

(

const bool &

exitIOThreadSignalled

)

Adds the 'I/O finished' packet to the packet queue. This functions as a command to the decode thread.

addPacket()

bool addPacket	(	AVPacket &	packet,
		const bool &	exitIOThreadSignalled
	)

Adds a packet to the packet queue.

Parameters

packet	The packet to add.
exitIOThreadSignalled	When I/O thread is in exit mode, this must be true.

Returns

if packet was added

addSeekEndPacket()

bool addSeekEndPacket	(	const bool &	exitIOThreadSignalled,
		double	seekTargetSecs
	)

Adds the 'seek end' packet to the packet queue. This functions as a command to the decode thread.

addSeekStartPacket()

bool addSeekStartPacket

(

const bool &

exitIOThreadSignalled

)

Adds the 'seek start' packet to the packet queue. This functions as a command to the decode thread.

cancelWaitForEndOfFileProcessed()

void cancelWaitForEndOfFileProcessed

(

)

Cancel any outstanding waits for end of file to be processed

cancelWaitForFrameQueueEmpty()

void cancelWaitForFrameQueueEmpty

(

)

Cancel any outstanding waits for the frame queue to be empty

clearFrameQueue()

void clearFrameQueue

(

)

Clears frame queue.

clearPacketQueue()

void clearPacketQueue

(

)

Clears packet queue.

close()

void close

(

)

Destroys codec.

drainSeekFrameQueue()

void drainSeekFrameQueue

(

)

Consumes all frames in the frame queue until the decode thread needs new packets.

exitDecodeThread()

void exitDecodeThread

(

bool

join

)

Stops the decode thread and blocks waiting for it to exit if join is true.

Parameters

join	If true, the function blocks until the thread is exited, otherwise false.

getCodec()

AVCodec& getCodec

(

)

Returns

audio or video codec used to decode packets into frames.

getCodecContext()

AVCodecContext& getCodecContext

(

)

Returns

audio or video codec context used to decode packets into frames.

getStream()

int getStream

(

)

const

Returns

Index of this stream.

init()

void init	(	int	stream,
		AVCodec *	codec,
		AVCodecContext *	codecContext
	)

Initializes stream and codec.

Parameters

stream	Video or audio stream index.
codec	codec to use
codecContext	context associated with the codec

isFinished()

bool isFinished

(

)

const

Returns

True when there are no more frames to produce (there are no more packets to decode) and all frames have been consumed by the client.

isValid()

bool isValid

(

)

const

Returns

whether object is initialized.

matchesStream()

bool matchesStream

(

const AVPacket &

packet

)

const

Returns

true when the packet belongs to the stream for this AVState.

notifyExitIOThread()

void notifyExitIOThread

(

)

Unblocks synchronization primitives for succesful exit of I/O thread.

notifyStartIOThread()

void notifyStartIOThread

(

)

Prepares for start of I/O thread, reset synchronization primitives.

peekFrame()

Frame peekFrame

(

)

Returns

If there was a frame on the queue, returns it without removing it from the queue.

popFrame()

Frame popFrame

(

)

Block until a frame can be popped from the queue.

Returns

The next frame on the queue. If the thread was exited during this operation, an empty frame is returned.

popSeekFrame()

Frame popSeekFrame

(

)

Returns

If there was a frame on the 'seek' frame queue, returns it without removing it from the queue.

resetEndOfFileProcessed()

void resetEndOfFileProcessed

(

)

Reset the state of the end of file processed event so that subsequent waits will wait normally

resetWaitForFrameQueueEmpty()

void resetWaitForFrameQueueEmpty

(

)

Reset the state of the frame queue so that subsequent waits will wait normally

startDecodeThread()

void startDecodeThread

(

const OnClearFrameQueueFunction &

onClearFrameQueueFunction = OnClearFrameQueueFunction()

)

Spawns the decode thread.

Parameters

onClearFrameQueueFunction

An optional function that can be used to perform additional work when the frame queue is cleared.

tryPopFrame()

Frame tryPopFrame

(

double

pts

)

Non-blocking popping of the next frame. The pts is checked to see if the next frame is equal or greater than the pts passed. If so, the frame is popped. Otherwise, an empty frame is returned.

Parameters

pts	The 'current time' that is tested against the frames' PTS.

waitForEndOfFileProcessed()

bool waitForEndOfFileProcessed

(

)

Blocks until the EOF packet that was added by addEndOfFilePacket is consumed by the decode thread.

waitForFrameQueueEmpty()

bool waitForFrameQueueEmpty

(

bool &

exitIOThreadSignalled

)

Wait for the frame to be empty

Parameters

exitIOThreadSignalled

When I/O thread is in exit mode, this must be true.

Returns

if the queue emptied.

waitForReceiveFrame()

int waitForReceiveFrame

(

)

Blocks until the decode thread has called avcoded_receive. This is used to perform lock-step production of packets and frames.

Returns

Result of avcoded_receive_frame

waitSeekStartPacketProcessed()

void waitSeekStartPacketProcessed

(

)

Blocks until the 'seek start' packet that was added by addSeekStartPacket is consumed by the decode thread.