jami::MediaFilter Class Reference

Provides access to libavfilter. More...

#include <media_filter.h>

Collaboration diagram for jami::MediaFilter:

Public Member Functions
int	feedInput (AVFrame *frame, const std::string &inputName)
	Give the specified source filter an input frame.
void	flush ()
	Flush filter to indicate EOF.
std::string	getFilterDesc () const
	Returns the current filter graph string.
const MediaStream &	getInputParams (const std::string &inputName) const
	Returns a MediaStream object describing the input specified by @inputName.
MediaStream	getOutputParams () const
	Returns a MediaStream struct describing the frames that will be output.
int	initialize (const std::string &filterDesc, const std::vector< MediaStream > &msps)
	Initializes the filter graph with one or more inputs and one output.
	MediaFilter ()
bool	needsReinitForNewStream (const std::string &name) const
	Determines if the media filter needs to be reinitialized for a new stream.
std::unique_ptr< MediaFrame >	readOutput ()
	Pull a frame from the filter graph.
	~MediaFilter ()

Detailed Description

Provides access to libavfilter.

Can be used for filters with unlimited number of inputs. Multiple outputs are not supported. They add complexity for little gain.

For information on how to write a filter graph description, see: https://ffmpeg.org/ffmpeg-filters.html http://trac.ffmpeg.org/wiki/FilteringGuide

It is required to name each filter graph input. These names are used to feed the correct input. It is the same name that will be passed as second argument to feedInput(AVFrame*, std::string).

Examples:

• "[in1] scale=320:240" Scales the input to 320x240.
• "[in1] scale=iw/4:ih/4 [mid]; [in2] [mid] overlay=main_w-overlay_w-10:main_h-overlay_h-10" in1 will be scaled to 1/16th its size and placed over in2 in the bottom right corner. When feeding frames to the filter, you need to specify whether the frame is destined for in1 or in2.

Definition at line 60 of file media_filter.h.

Constructor & Destructor Documentation

MediaFilter()

jami::MediaFilter::MediaFilter

(

)

Definition at line 35 of file media_filter.cpp.

~MediaFilter()

jami::MediaFilter::~MediaFilter

(

)

Definition at line 37 of file media_filter.cpp.

Member Function Documentation

feedInput()

int jami::MediaFilter::feedInput	(	AVFrame *	frame,
		const std::string &	inputName
	)

Give the specified source filter an input frame.

Caller is responsible for freeing the frame.

NOTE Will fail if @inputName is not found in the graph.

Definition at line 159 of file media_filter.cpp.

References jami::emitSignal().

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flush()

void jami::MediaFilter::flush

(

)

Flush filter to indicate EOF.

Definition at line 229 of file media_filter.cpp.

References jami::emitSignal(), jami::libav_utils::getError(), and JAMI_ERR.

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getFilterDesc()

std::string jami::MediaFilter::getFilterDesc

(

)

const

Returns the current filter graph string.

Definition at line 43 of file media_filter.cpp.

getInputParams()

const MediaStream & jami::MediaFilter::getInputParams

(

const std::string &

inputName

)

const

Returns a MediaStream object describing the input specified by @inputName.

Definition at line 115 of file media_filter.cpp.

References jami::emitSignal().

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getOutputParams()

MediaStream jami::MediaFilter::getOutputParams

(

)

const

Returns a MediaStream struct describing the frames that will be output.

When called in an invalid state, the returned format will be invalid (less than 0).

Definition at line 124 of file media_filter.cpp.

References jami::emitSignal().

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initialize()

int jami::MediaFilter::initialize	(	const std::string &	filterDesc,
		const std::vector< MediaStream > &	msps
	)

Initializes the filter graph with one or more inputs and one output.

Returns a negative code on error.

Definition at line 49 of file media_filter.cpp.

References jami::emitSignal(), and JAMI_DBG.

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needsReinitForNewStream()

bool jami::MediaFilter::needsReinitForNewStream

(

const std::string &

name

)

const

Determines if the media filter needs to be reinitialized for a new stream.

Definition at line 106 of file media_filter.cpp.

readOutput()

std::unique_ptr< MediaFrame > jami::MediaFilter::readOutput

(

)

Pull a frame from the filter graph.

Caller owns the frame reference.

Returns AVERROR(EAGAIN) if filter graph requires more input.

NOTE Frame reference belongs to the caller

Definition at line 195 of file media_filter.cpp.

References jami::emitSignal(), and JAMI_WARN.

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

• media_filter.h
• media_filter.cpp