OpalVideoTranscoder Class Reference

#include <vidcodec.h>

Inheritance diagram for OpalVideoTranscoder:

Public Types
typedef PluginCodec_Video_FrameHeader	FrameHeader
Public Member Functions
Construction

	OpalVideoTranscoder (const OpalMediaFormat &inputMediaFormat, const OpalMediaFormat &outputMediaFormat)
Operations

virtual bool	UpdateMediaFormats (const OpalMediaFormat &inputMediaFormat, const OpalMediaFormat &outputMediaFormat)
virtual PINDEX	GetOptimalDataFrameSize (PBoolean input) const
virtual PBoolean	ExecuteCommand (const OpalMediaCommand &command)
virtual PBoolean	Convert (const RTP_DataFrame &input, RTP_DataFrame &output)
virtual void	GetStatistics (OpalMediaStatistics &statistics) const
bool	WasLastFrameIFrame () const
void	ForceIFrame ()
PINDEX	GetMaxEncoderOutputSize () const
Protected Attributes
PINDEX	inDataSize
PINDEX	outDataSize
PINDEX	videoEncoderMaxOutputSize
bool	forceIFrame
bool	lastFrameWasIFrame
DWORD	m_totalFrames
DWORD	m_keyFrames

Detailed Description

This class defines a transcoder implementation class that will encode/decode video.

An application may create a descendent off this class and override functions as required for descibing a specific transcoder.

Member Typedef Documentation

typedef PluginCodec_Video_FrameHeader OpalVideoTranscoder::FrameHeader

Constructor & Destructor Documentation

OpalVideoTranscoder::OpalVideoTranscoder	(	const OpalMediaFormat &	inputMediaFormat,
		const OpalMediaFormat &	outputMediaFormat
	)

Create a new video transcoder implementation.

Parameters:

	inputMediaFormat	Input media format
	outputMediaFormat	Output media format

Member Function Documentation

virtual PBoolean OpalVideoTranscoder::Convert	(	const RTP_DataFrame &	input,
		RTP_DataFrame &	output
	)			`[virtual]`

Convert the data from one format to another. This function takes the input data as a RTP_DataFrame and converts it to its output format, placing it into the RTP_DataFrame provided.

This is a dummy function as nearly all video conversion will does not have a one to one input to output frames ratio, so the ConvertFrames() function is used instead.

Returns PFalse if the conversion fails.

Parameters:

	input	Input data
	output	Output data

Implements OpalTranscoder.

virtual PBoolean OpalVideoTranscoder::ExecuteCommand ( const OpalMediaCommand & command ) [virtual]

Execute the command specified to the transcoder. The commands are highly context sensitive, for example VideoFastUpdate would only apply to a video transcoder.

The default behaviour checks for a OpalVideoUpdatePicture and sets the updatePicture member variable if that is the command.

Parameters:

command

Command to execute.

Reimplemented from OpalTranscoder.

Reimplemented in OpalPluginVideoTranscoder.

void OpalVideoTranscoder::ForceIFrame ( ) [inline]

References forceIFrame.

PINDEX OpalVideoTranscoder::GetMaxEncoderOutputSize ( ) const [inline]

References videoEncoderMaxOutputSize.

virtual PINDEX OpalVideoTranscoder::GetOptimalDataFrameSize ( PBoolean input ) const [virtual]

Get the optimal size for data frames to be converted. This function returns the size of frames that will be most efficient in conversion. A RTP_DataFrame will attempt to provide or use data in multiples of this size. Note that it may not do so, so the transcoder must be able to handle any sized packets.

Parameters:

input

Flag for input or output data size

Implements OpalTranscoder.

virtual void OpalVideoTranscoder::GetStatistics ( OpalMediaStatistics & statistics ) const [virtual]

Reimplemented from OpalTranscoder.

virtual bool OpalVideoTranscoder::UpdateMediaFormats	(	const OpalMediaFormat &	inputMediaFormat,
		const OpalMediaFormat &	outputMediaFormat
	)			`[virtual]`

Update the input and output media formats. This can be used to adjust the parameters of a codec at run time. Note you cannot change the basic media format, eg change GSM0610 to G.711, only options for that format, eg 6k3 mode to 5k3 mode in G.723.1. If the formats are different then a OpalMediaFormat::Merge() is performed.

If a format is empty (invalid) it is ignored and does not update the internal variable. In this way only the input or output side can be updated.

The default behaviour updates the inputMediaFormat and outputMediaFormat member variables.

Parameters: