openshot::ChunkWriter Class Reference

This class takes any reader and generates a special type of video file, built with chunks of small video and audio data. More...

#include <ChunkWriter.h>

Inheritance diagram for openshot::ChunkWriter:

Public Member Functions
	ChunkWriter (string path, ReaderBase *reader)
	Constructor for ChunkWriter. Throws one of the following exceptions. More...
void	Close ()
	Close the writer. More...
int64_t	GetChunkSize ()
	Get the chunk size (number of frames to write in each chunk) More...
bool	IsOpen ()
	Determine if writer is open or closed. More...
void	Open ()
	Open writer. More...
void	SetChunkSize (int64_t new_size)
	Set the chunk size (number of frames to write in each chunk) More...
void	WriteFrame (std::shared_ptr< Frame > frame)
	Add a frame to the stack waiting to be encoded. More...
void	WriteFrame (int64_t start, int64_t length)
	Write a block of frames from a reader. More...
void	WriteFrame (ReaderBase *reader, int64_t start, int64_t length)
	Write a block of frames from a reader. More...
Public Member Functions inherited from openshot::WriterBase
void	CopyReaderInfo (ReaderBase *reader)
	This method copy's the info struct of a reader, and sets the writer with the same info. More...
void	DisplayInfo ()
	Display file information in the standard output stream (stdout) More...
string	Json ()
	Get and Set JSON methods. More...
Json::Value	JsonValue ()
	Generate Json::JsonValue for this object. More...
void	SetJson (string value)
	Load JSON string into this object. More...
void	SetJsonValue (Json::Value root)
	Load Json::JsonValue into this object. More...
	WriterBase ()
	Constructor for WriterBase class, many things are initialized here. More...

Additional Inherited Members
Public Attributes inherited from openshot::WriterBase
WriterInfo	info
	Information about the current media file. More...

Detailed Description

This class takes any reader and generates a special type of video file, built with chunks of small video and audio data.

These chunks can easily be passed around in a distributed computing environment, without needing to share the entire video file. They also allow a chunk to be frame accurate, since seeking inaccuracies are removed.

// This example demonstrates how to feed a reader into a ChunkWriter
FFmpegReader *r = new FFmpegReader("MyAwesomeVideo.mp4"); // Get a reader
r.Open(); // Open the reader

// Create a ChunkWriter (and a folder location on your computer)
ChunkWriter w("/folder_path_to_hold_chunks/", r);

// Open the writer
w.Open();

// Write a block of frames to the ChunkWriter (from frame 1 to the end)
w.WriteFrame(r, 1, r->info.video_length);

// Close the reader & writer
w.Close();
r.Close();

Definition at line 80 of file ChunkWriter.h.

Constructor & Destructor Documentation

ChunkWriter()

ChunkWriter::ChunkWriter	(	string	path,
		ReaderBase *	reader
	)

Constructor for ChunkWriter. Throws one of the following exceptions.

Parameters

path	The folder path of the chunk file to be created
reader	The initial reader to base this chunk file's meta data on (such as fps, height, width, etc...)

Definition at line 32 of file ChunkWriter.cpp.

Member Function Documentation

Close()

void ChunkWriter::Close

(

)

Close the writer.

Definition at line 224 of file ChunkWriter.cpp.

GetChunkSize()

int64_t openshot::ChunkWriter::GetChunkSize ( )

inline

Get the chunk size (number of frames to write in each chunk)

Definition at line 122 of file ChunkWriter.h.

IsOpen()

bool openshot::ChunkWriter::IsOpen ( )

inlinevirtual

Determine if writer is open or closed.

Implements openshot::WriterBase.

Definition at line 125 of file ChunkWriter.h.

Open()

void ChunkWriter::Open ( )

virtual

Open writer.

Implements openshot::WriterBase.

Definition at line 299 of file ChunkWriter.cpp.

SetChunkSize()

void openshot::ChunkWriter::SetChunkSize ( int64_t  new_size )

inline

Set the chunk size (number of frames to write in each chunk)

Parameters

new_size

The number of frames to write in this chunk file

Definition at line 132 of file ChunkWriter.h.

WriteFrame() [1/3]

void ChunkWriter::WriteFrame ( std::shared_ptr< Frame >  frame )

virtual

Add a frame to the stack waiting to be encoded.

Parameters

frame

The openshot::Frame object that needs to be written to this chunk file.

Implements openshot::WriterBase.

Definition at line 77 of file ChunkWriter.cpp.

WriteFrame() [2/3]

void ChunkWriter::WriteFrame	(	int64_t	start,
		int64_t	length
	)

Write a block of frames from a reader.

Parameters

start	The starting frame number to write (of the reader passed into the constructor)
length	The number of frames to write (of the reader passed into the constructor)

Definition at line 210 of file ChunkWriter.cpp.

WriteFrame() [3/3]

void ChunkWriter::WriteFrame ( ReaderBase *  reader, int64_t  start, int64_t  length  )

virtual

Write a block of frames from a reader.

Parameters

reader	The reader containing the frames you need
start	The starting frame number to write
length	The number of frames to write

Implements openshot::WriterBase.

Definition at line 196 of file ChunkWriter.cpp.

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

• ChunkWriter.h
• ChunkWriter.cpp