WriterBase.h

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/**
 * @file
 * @brief Header file for WriterBase class
 * @author Jonathan Thomas <jonathan@openshot.org>
 *
 * @section LICENSE
 *
 * Copyright (c) 2008-2014 OpenShot Studios, LLC
 * <http://www.openshotstudios.com/>. This file is part of
 * OpenShot Library (libopenshot), an open-source project dedicated to
 * delivering high quality video editing and animation solutions to the
 * world. For more information visit <http://www.openshot.org/>.
 *
 * OpenShot Library (libopenshot) is free software: you can redistribute it
 * and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * OpenShot Library (libopenshot) is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef OPENSHOT_WRITER_BASE_H
#define OPENSHOT_WRITER_BASE_H

#include <iostream>
#include <iomanip>
#include "ChannelLayouts.h"
#include "Fraction.h"
#include "Frame.h"
#include "ReaderBase.h"
#include "ZmqLogger.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 WriterBase 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
                bool has_single_image;          ///< Determines if this file only contains a single image
                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 pixels)
                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
                ChannelLayout channel_layout;   ///< The channel layout (mono, stereo, 5 point surround, etc...)
                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 WriterBase
        {
        protected:

                /// Append debug information as JSON
                void AppendDebugMethod(string method_name, string arg1_name, float arg1_value,
                                                                                                   string arg2_name, float arg2_value,
                                                                                                   string arg3_name, float arg3_value,
                                                                                                   string arg4_name, float arg4_value,
                                                                                                   string arg5_name, float arg5_value,
                                                                                                   string arg6_name, float arg6_value);

        public:
                /// Constructor for WriterBase class, many things are initialized here
                WriterBase();

                /// Enable or disable debug output. Output will display on the standard output, and you can
                /// optionally invoke the OutputDebugJSON() method, which will format the debug output as JSON.
                bool debug;

                /// Information about the current media file
                WriterInfo info;

                /// @brief This method copy's the info struct of a reader, and sets the writer with the same info
                /// @param reader The source reader to copy
                void CopyReaderInfo(ReaderBase* reader);

                /// Determine if writer is open or closed
                virtual bool IsOpen() = 0;

                /// This method is required for all derived classes of WriterBase.  Write a Frame to the video file.
                virtual void WriteFrame(tr1::shared_ptr<Frame> frame) throw(ErrorEncodingVideo, WriterClosed) = 0;

                /// This method is required for all derived classes of WriterBase.  Write a block of frames from a reader.
                virtual void WriteFrame(ReaderBase* reader, long int start, long int length) throw(ErrorEncodingVideo, WriterClosed) = 0;

                /// Get and Set JSON methods
                string Json(); ///< Generate JSON string of this object
                Json::Value JsonValue(); ///< Generate Json::JsonValue for this object
                void SetJson(string value) throw(InvalidJSON); ///< Load JSON string into this object
                void SetJsonValue(Json::Value root); ///< Load Json::JsonValue into this object

                /// Display file information in the standard output stream (stdout)
                void DisplayInfo();

                /// Open the writer (and start initializing streams)
                virtual void Open() = 0;
        };

}

#endif