PreviewGenerator Class Reference

#include <previewgenerator.h>

Detailed Description

This class creates a preview image of a recording.

The usage is simple: First, pass a ProgramInfo whose pathname points to a local or remote recording to the constructor. Then call either Start(void) or Run(void) to generate the preview.

Start(void) will create a thread that processes the request, creating a sockets the the backend if the recording is not local.

Run(void) will process the request in the current thread, and it uses the MythContext's server and event sockets if the recording is not local.

The PreviewGenerator will send Qt signals when the preview is ready and when the preview thread finishes running if Start(void) was called.

Definition at line 15 of file previewgenerator.h.


Public Slots
void	deleteLater ()
Signals
void	previewThreadDone (const QString &, bool &)
void	previewReady (const ProgramInfo *)
Public Member Functions
	PreviewGenerator (const ProgramInfo *pginfo, bool local_only=true)
	Constructor.
void	SetPreviewTime (long long time, bool in_seconds)
void	SetPreviewTimeAsSeconds (long long seconds_in)
void	SetPreviewTimeAsFrameNumber (long long frame_number)
void	SetOutputFilename (const QString &)
void	SetOutputSize (const QSize &size)
void	Start (void)
	This call starts a thread that will create a preview.
bool	Run (void)
void	AttachSignals (QObject *)
void	disconnectSafe (void)
	disconnects signals while holding previewLock, ensuring that no one will receive a signal from this class after this call.
Static Public Attributes
static const char *	kInUseID = "preview_generator"
Protected Member Functions
virtual	~PreviewGenerator ()
void	TeardownAll (void)
bool	RemotePreviewSetup (void)
bool	RemotePreviewRun (void)
void	RemotePreviewTeardown (void)
bool	LocalPreviewRun (void)
bool	IsLocal (void) const
bool	RunReal (void)
	This call creates a preview without starting a new thread.
Static Protected Member Functions
static void *	PreviewRun (void *)
static char *	GetScreenGrab (const ProgramInfo *pginfo, const QString &filename, long long seektime, bool time_in_secs, int &bufferlen, int &video_width, int &video_height, float &video_aspect)
	Returns a PIX_FMT_RGBA32 buffer containg a frame from the video.
static bool	SavePreview (QString filename, const unsigned char *data, uint width, uint height, float aspect, int desired_width, int desired_height)
static QString	CreateAccessibleFilename (const QString &pathname, const QString &outFileName)
Protected Attributes
QMutex	previewLock
pthread_t	previewThread
ProgramInfo	programInfo
bool	localOnly
bool	isConnected
bool	createSockets
MythSocket *	serverSock
QString	pathname
bool	timeInSeconds
	tells us whether to use time as seconds or frame number
long long	captureTime
	snapshot time in seconds or frame number, depending on timeInSeconds
QString	outFileName
QSize	outSize
Friends
int	preview_helper (const QString &chanid, const QString &starttime, long long previewFrameNumber, long long previewSeconds, const QSize &previewSize, const QString &infile, const QString &outfile)

Constructor & Destructor Documentation

PreviewGenerator::PreviewGenerator	(	const ProgramInfo *	pginfo,
		bool	local_only = `true`
	)

Constructor.

ProgramInfo::pathname must include recording prefix, so that the file can be found on the file system for local preview generation. When called by the backend 'local_only' should be set to true, otherwise the backend may deadlock if the PreviewGenerator can not find the file.

Parameters:

	pginfo	ProgramInfo for the recording we want a preview of.
	local_only	If set to true, the preview will only be generated if the file is local.

Definition at line 66 of file previewgenerator.cpp.

PreviewGenerator::~PreviewGenerator ( ) [protected, virtual]

Definition at line 93 of file previewgenerator.cpp.

Member Function Documentation

void PreviewGenerator::SetPreviewTime	(	long long	time,
		bool	in_seconds
	)			`[inline]`

Definition at line 29 of file previewgenerator.h.

Referenced by MainServer::HandleGenPreviewPixmap().

void PreviewGenerator::SetPreviewTimeAsSeconds ( long long seconds_in ) [inline]

Definition at line 31 of file previewgenerator.h.

Referenced by MythXML::GetPreviewImage(), and preview_helper().

void PreviewGenerator::SetPreviewTimeAsFrameNumber ( long long frame_number ) [inline]

Definition at line 33 of file previewgenerator.h.

Referenced by preview_helper(), NetworkControl::saveScreenshot(), and TV::ScreenShot().

void PreviewGenerator::SetOutputFilename ( const QString & fileName )

Definition at line 98 of file previewgenerator.cpp.

Referenced by MythXML::GetPreviewImage(), MainServer::HandleGenPreviewPixmap(), preview_helper(), NetworkControl::saveScreenshot(), and TV::ScreenShot().

void PreviewGenerator::SetOutputSize ( const QSize & size ) [inline]

Definition at line 36 of file previewgenerator.h.

Referenced by MainServer::HandleGenPreviewPixmap(), preview_helper(), NetworkControl::saveScreenshot(), and TV::ScreenShot().

void PreviewGenerator::Start ( void )

This call starts a thread that will create a preview.

Definition at line 156 of file previewgenerator.cpp.

bool PreviewGenerator::Run ( void )

Definition at line 194 of file previewgenerator.cpp.

Referenced by MythXML::GetPreviewImage(), MainServer::HandleGenPreviewPixmap(), PreviewRun(), NetworkControl::saveScreenshot(), and TV::ScreenShot().

void PreviewGenerator::AttachSignals ( QObject * obj )

Definition at line 132 of file previewgenerator.cpp.

Referenced by PlaybackBox::SetPreviewGenerator().

void PreviewGenerator::disconnectSafe ( void )

disconnects signals while holding previewLock, ensuring that no one will receive a signal from this class after this call.

Definition at line 146 of file previewgenerator.cpp.

Referenced by TeardownAll().

void PreviewGenerator::previewThreadDone	(	const QString &	,
		bool &
	)			`[signal]`

Referenced by AttachSignals(), and TeardownAll().

void PreviewGenerator::previewReady ( const ProgramInfo * ) [signal]

Referenced by AttachSignals(), and Run().

void PreviewGenerator::deleteLater ( void ) [slot]

Definition at line 126 of file previewgenerator.cpp.

Referenced by MythXML::GetPreviewImage(), MainServer::HandleGenPreviewPixmap(), preview_helper(), PreviewRun(), NetworkControl::saveScreenshot(), and TV::ScreenShot().

void PreviewGenerator::TeardownAll ( void ) [protected]

Definition at line 103 of file previewgenerator.cpp.

Referenced by deleteLater(), and ~PreviewGenerator().

bool PreviewGenerator::RemotePreviewSetup ( void ) [protected]

Definition at line 283 of file previewgenerator.cpp.

Referenced by RemotePreviewRun().

bool PreviewGenerator::RemotePreviewRun ( void ) [protected]

Definition at line 292 of file previewgenerator.cpp.

Referenced by Run(), and RunReal().

void PreviewGenerator::RemotePreviewTeardown ( void ) [protected]

Definition at line 414 of file previewgenerator.cpp.

Referenced by RemotePreviewRun().

bool PreviewGenerator::LocalPreviewRun ( void ) [protected]

Definition at line 492 of file previewgenerator.cpp.

Referenced by RunReal().

bool PreviewGenerator::IsLocal ( void ) const [protected]

Definition at line 558 of file previewgenerator.cpp.

Referenced by PreviewGenerator(), Run(), and RunReal().

bool PreviewGenerator::RunReal ( void ) [protected]

This call creates a preview without starting a new thread.

Definition at line 166 of file previewgenerator.cpp.

Referenced by preview_helper().

void * PreviewGenerator::PreviewRun ( void * param ) [static, protected]

Definition at line 271 of file previewgenerator.cpp.

Referenced by Start().

char * PreviewGenerator::GetScreenGrab	(	const ProgramInfo *	pginfo,
		const QString &	filename,
		long long	seektime,
		bool	time_in_secs,
		int &	bufferlen,
		int &	video_width,
		int &	video_height,
		float &	video_aspect
	)			`[static, protected]`

Returns a PIX_FMT_RGBA32 buffer containg a frame from the video.

Parameters:

	pginfo	Recording to grab from.
	filename	File containing recording.
	seektime	Seconds or frames into the video to seek before capturing a frame.
	time_in_secs	if true time is in seconds, otherwise it is in frames.
	bufferlen	Returns size of buffer returned (in bytes).
	video_width	Returns width of frame grabbed.
	video_height	Returns height of frame grabbed.
	video_aspect	Returns aspect ratio of frame grabbed.

Returns:: Buffer allocated with new containing frame in RGBA32 format if successful, NULL otherwise.

Definition at line 580 of file previewgenerator.cpp.

Referenced by LocalPreviewRun().

bool PreviewGenerator::SavePreview	(	QString	filename,
		const unsigned char *	data,
		uint	width,
		uint	height,
		float	aspect,
		int	desired_width,
		int	desired_height
	)			`[static, protected]`

Definition at line 423 of file previewgenerator.cpp.

Referenced by LocalPreviewRun().

QString PreviewGenerator::CreateAccessibleFilename	(	const QString &	pathname,
		const QString &	outFileName
	)			`[static, protected]`

Definition at line 527 of file previewgenerator.cpp.

Referenced by LocalPreviewRun(), and RemotePreviewRun().

Friends And Related Function Documentation

int preview_helper	(	const QString &	chanid,
		const QString &	starttime,
		long long	previewFrameNumber,
		long long	previewSeconds,
		const QSize &	previewSize,
		const QString &	infile,
		const QString &	outfile
	)			`[friend]`