cv::cudacodec::VideoReader Class Reference

Video reader interface. More...

#include <opencv2/cudacodec.hpp>

Public Member Functions
virtual	~VideoReader ()
virtual FormatInfo	format () const =0
	Returns information about video file format. More...
virtual int	get (const VideoReaderProps property, const int propertyVal=-1) const =0
	Returns the specified VideoReader property. More...
virtual bool	grab (Stream &stream=Stream::Null())=0
	Grabs the next frame from the video source. More...
virtual bool	nextFrame (GpuMat &frame, Stream &stream=Stream::Null())=0
	Grabs, decodes and returns the next video frame. More...
virtual bool	retrieve (OutputArray frame, const size_t idx=static_cast< size_t >(VideoReaderProps::PROP_DECODED_FRAME_IDX)) const =0
	Returns previously grabbed video data. More...
virtual bool	set (const VideoReaderProps property, const double propertyVal)=0
	Sets a property in the VideoReader. More...

Detailed Description

Video reader interface.

Note

• An example on how to use the videoReader class can be found at opencv_source_code/samples/gpu/video_reader.cpp

Constructor & Destructor Documentation

~VideoReader()

virtual cv::cudacodec::VideoReader::~VideoReader ( )

inlinevirtual

Member Function Documentation

format()

virtual FormatInfo cv::cudacodec::VideoReader::format ( ) const

pure virtual

Returns information about video file format.

get()

virtual int cv::cudacodec::VideoReader::get ( const VideoReaderProps  property, const int  propertyVal = -1  ) const

pure virtual

Returns the specified VideoReader property.

Parameters

property	Property identifier from cv::cudacodec::VideoReaderProps (eg. cv::cudacodec::PROP_DECODED_FRAME_IDX, cv::cudacodec::PROP_EXTRA_DATA_INDEX, ...)
propertyVal	Optional value for the property.

Returns

Value for the specified property. Value -1 is returned when querying a property that is not supported.

grab()

virtual bool cv::cudacodec::VideoReader::grab ( Stream &  stream = Stream::Null() )

pure virtual

Grabs the next frame from the video source.

Returns

true (non-zero) in the case of success.

The method/function grabs the next frame from video file or camera and returns true (non-zero) in the case of success.

The primary use of the function is for reading both the encoded and decoded video data when rawMode is enabled. With rawMode enabled retrieve() can be called following grab() to retrieve all the data associated with the current video source since the last call to grab() or the creation of the VideoReader.

nextFrame()

virtual bool cv::cudacodec::VideoReader::nextFrame ( GpuMat &  frame, Stream &  stream = Stream::Null()  )

pure virtual

Grabs, decodes and returns the next video frame.

If no frames has been grabbed (there are no more frames in video file), the methods return false . The method throws Exception if error occurs.

retrieve()

virtual bool cv::cudacodec::VideoReader::retrieve ( OutputArray  frame, const size_t  idx = static_cast< size_t >(VideoReaderProps::PROP_DECODED_FRAME_IDX)  ) const

pure virtual

Returns previously grabbed video data.

Parameters

[out]	frame	The returned data which depends on the provided idx. If there is no new data since the last call to grab() the image will be empty.
	idx	Determins the returned data inside image. The returned data can be the: Decoded frame, idx = get(PROP_DECODED_FRAME_IDX). Extra data if available, idx = get(PROP_EXTRA_DATA_INDEX). Raw encoded data package. To retrieve package i, idx = get(PROP_RAW_PACKAGES_BASE_INDEX) + i with i < get(PROP_NUMBER_OF_RAW_PACKAGES_SINCE_LAST_GRAB)

Returns

false if no frames has been grabbed

The method returns data associated with the current video source since the last call to grab() or the creation of the VideoReader. If no data is present the method returns false and the function returns an empty image.

set()

virtual bool cv::cudacodec::VideoReader::set ( const VideoReaderProps  property, const double  propertyVal  )

pure virtual

Sets a property in the VideoReader.

Parameters

property	Property identifier from cv::cudacodec::VideoReaderProps (eg. cv::cudacodec::PROP_DECODED_FRAME_IDX, cv::cudacodec::PROP_EXTRA_DATA_INDEX, ...)
propertyVal	Value of the property.

Returns

true if the property has been set.

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

• opencv2/cudacodec.hpp