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libopenshot/include/FileWriterBase.h

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3.4 KiB
C++

#ifndef OPENSHOT_FILE_WRITER_BASE_H
#define OPENSHOT_FILE_WRITER_BASE_H
/**
* \file
* \brief Header file for FileWriterBase class
* \author Copyright (c) 2011 Jonathan Thomas
*/
#include <iostream>
#include <iomanip>
#include "Fraction.h"
#include "Frame.h"
#include "FileReaderBase.h"
using namespace std;
namespace openshot
{
/**
* \brief This struct contains info about encoding a media file, such as height, width, frames per second, etc...
*
* Each derived class of FileWriterBase is responsible for updating this struct to reflect accurate information
* about the streams.
*/
struct WriterInfo
{
bool has_video; ///< Determines if this file has a video stream
bool has_audio; ///< Determines if this file has an audio stream
float duration; ///< Length of time (in seconds)
int file_size; ///< Size of file (in bytes)
int height; ///< The height of the video (in pixels)
int width; ///< The width of the video (in pixesl)
int pixel_format; ///< The pixel format (i.e. YUV420P, RGB24, etc...)
Fraction fps; ///< Frames per second, as a fraction (i.e. 24/1 = 24 fps)
int video_bit_rate; ///< The bit rate of the video stream (in bytes)
Fraction pixel_ratio; ///< The pixel ratio of the video stream as a fraction (i.e. some pixels are not square)
Fraction display_ratio; ///< The ratio of width to height of the video stream (i.e. 640x480 has a ratio of 4/3)
string vcodec; ///< The name of the video codec used to encode / decode the video stream
long int video_length; ///< The number of frames in the video stream
int video_stream_index; ///< The index of the video stream
Fraction video_timebase; ///< The video timebase determines how long each frame stays on the screen
bool interlaced_frame; // Are the contents of this frame interlaced
bool top_field_first; // Which interlaced field should be displayed first
string acodec; ///< The name of the audio codec used to encode / decode the video stream
int audio_bit_rate; ///< The bit rate of the audio stream (in bytes)
int sample_rate; ///< The number of audio samples per second (44100 is a common sample rate)
int channels; ///< The number of audio channels used in the audio stream
int audio_stream_index; ///< The index of the audio stream
Fraction audio_timebase; ///< The audio timebase determines how long each audio packet should be played
};
/**
* \brief This abstract class is the base class, used by writers. Writers are types of classes that encode
* video, audio, and image files.
*
* The only requirements for a 'writer', are to derive from this base class, and implement the
* WriteFrame method.
*/
class FileWriterBase
{
public:
/// Information about the current media file
WriterInfo info;
/// This method is required for all derived classes of FileWriterBase. Write a Frame to the video file.
virtual void WriteFrame(tr1::shared_ptr<Frame> frame) = 0;
/// This method is required for all derived classes of FileWriterBase. Write a block of frames from a reader.
virtual void WriteFrame(FileReaderBase* reader, int start, int length) = 0;
/// Initialize the values of the WriterInfo struct. It is important for derived classes to call
/// this method, or the WriterInfo struct values will not be initialized.
void InitFileInfo();
/// Display file information in the standard output stream (stdout)
void DisplayInfo();
};
}
#endif