OpenShot Library | libopenshot 0.3.3
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ImageWriter.cpp
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1
9// Copyright (c) 2008-2019 OpenShot Studios, LLC, Fabrice Bellard
10//
11// SPDX-License-Identifier: LGPL-3.0-or-later
12
13//Require ImageMagick support
14#ifdef USE_IMAGEMAGICK
15
16#include "MagickUtilities.h"
17#include "QtUtilities.h"
18
19#include "ImageWriter.h"
20#include "Exceptions.h"
21#include "Frame.h"
22#include "ReaderBase.h"
23#include "ZmqLogger.h"
24
25using namespace openshot;
26
28 path(path), cache_size(8), write_video_count(0), image_quality(75), number_of_loops(1),
29 combine_frames(true), is_open(false)
30{
31 info.has_audio = false;
32 info.has_video = true;
33}
34
35// Set video export options
37 std::string format, Fraction fps, int width, int height,
38 int quality, int loops, bool combine)
39{
40 // Set frames per second (if provided)
41 info.fps = fps;
42
43 // Set image magic properties
44 image_quality = quality;
45 number_of_loops = loops;
46 combine_frames = combine;
47 info.vcodec = format;
48
49 // Set the timebase (inverse of fps)
51
52 info.width = std::max(1, width);
53 info.height = std::max(1, height);
54
55 info.video_bit_rate = quality;
56
57 // Calculate the DAR (display aspect ratio)
58 Fraction size(
61
62 // Reduce size fraction
63 size.Reduce();
64
65 // Set the ratio based on the reduced fraction
66 info.display_ratio = size;
67
69 "ImageWriter::SetVideoOptions (" + format + ")",
70 "width", width,
71 "height", height,
72 "size.num", size.num,
73 "size.den", size.den,
74 "fps.num", fps.num,
75 "fps.den", fps.den);
76}
77
78// Open the writer
80{
81 is_open = true;
82}
83
84// Add a frame to the queue waiting to be encoded.
85void ImageWriter::WriteFrame(std::shared_ptr<Frame> frame)
86{
87 // Check for open reader (or throw exception)
88 if (!is_open) {
89 throw WriterClosed(
90 "The ImageWriter is closed. "
91 "Call Open() before calling this method.", path);
92 }
93
94 // Copy and resize image
95 auto qimage = frame->GetImage();
96 auto frame_image = openshot::QImage2Magick(qimage);
97 frame_image->magick( info.vcodec );
98 frame_image->backgroundColor(Magick::Color("none"));
99 MAGICK_IMAGE_ALPHA(frame_image, true);
100 frame_image->quality(image_quality);
101 frame_image->animationDelay(info.video_timebase.ToFloat() * 100);
102 frame_image->animationIterations(number_of_loops);
103
104 // Calculate correct DAR (display aspect ratio)
105 int new_height = info.height * frame->GetPixelRatio().Reciprocal().ToDouble();
106
107 // Resize image
108 Magick::Geometry new_size(info.width, new_height);
109 new_size.aspect(true);
110 frame_image->resize(new_size);
111
112
113 // Put resized frame in vector (waiting to be written)
114 frames.push_back(*frame_image.get());
115
116 // Keep track of the last frame added
117 last_frame = frame;
118}
119
120// Write a block of frames from a reader
121void ImageWriter::WriteFrame(ReaderBase* reader, int64_t start, int64_t length)
122{
124 "ImageWriter::WriteFrame (from Reader)",
125 "start", start,
126 "length", length);
127
128 // Loop through each frame (and encoded it)
129 for (int64_t number = start; number <= length; number++)
130 {
131 // Get the frame
132 std::shared_ptr<Frame> f = reader->GetFrame(number);
133
134 // Encode frame
135 WriteFrame(f);
136 }
137}
138
139// Close the writer and encode/output final image to the disk.
141{
142 // Write frame images to file
143 Magick::writeImages(frames.begin(), frames.end(), path, combine_frames);
144
145 // Clear frames vector & counters, close writer
146 frames.clear();
147 write_video_count = 0;
148 is_open = false;
149
150 ZmqLogger::Instance()->AppendDebugMethod("ImageWriter::Close");
151}
152
153#endif //USE_IMAGEMAGICK
Header file for all Exception classes.
Header file for Frame class.
Header file for ImageWriter class.
Header file for MagickUtilities (IM6/IM7 compatibility overlay)
#define MAGICK_IMAGE_ALPHA(im, a)
Header file for QtUtilities (compatibiity overlay)
Header file for ReaderBase class.
Header file for ZeroMQ-based Logger class.
This class represents a fraction.
Definition Fraction.h:30
int num
Numerator for the fraction.
Definition Fraction.h:32
float ToFloat()
Return this fraction as a float (i.e. 1/2 = 0.5)
Definition Fraction.cpp:35
void Reduce()
Reduce this fraction (i.e. 640/480 = 4/3)
Definition Fraction.cpp:65
Fraction Reciprocal() const
Return the reciprocal as a Fraction.
Definition Fraction.cpp:78
int den
Denominator for the fraction.
Definition Fraction.h:33
void Close()
Close the writer and encode/output final image to the disk. This is a requirement of ImageMagick,...
ImageWriter(std::string path)
Constructor for ImageWriter. Throws one of the following exceptions.
void SetVideoOptions(std::string format, Fraction fps, int width, int height, int quality, int loops, bool combine)
Set the video export options.
void WriteFrame(std::shared_ptr< Frame > frame)
Add a frame to the stack waiting to be encoded.
void Open()
Open writer.
This abstract class is the base class, used by all readers in libopenshot.
Definition ReaderBase.h:76
virtual std::shared_ptr< openshot::Frame > GetFrame(int64_t number)=0
WriterInfo info
Information about the current media file.
Definition WriterBase.h:76
Exception when a writer is closed, and a frame is requested.
Definition Exceptions.h:416
void AppendDebugMethod(std::string method_name, std::string arg1_name="", float arg1_value=-1.0, std::string arg2_name="", float arg2_value=-1.0, std::string arg3_name="", float arg3_value=-1.0, std::string arg4_name="", float arg4_value=-1.0, std::string arg5_name="", float arg5_value=-1.0, std::string arg6_name="", float arg6_value=-1.0)
Append debug information.
static ZmqLogger * Instance()
Create or get an instance of this logger singleton (invoke the class with this method)
Definition ZmqLogger.cpp:35
This namespace is the default namespace for all code in the openshot library.
Definition Compressor.h:29
std::shared_ptr< Magick::Image > QImage2Magick(std::shared_ptr< QImage >)
Convert QImage to Magick::Image.
int height
The height of the video (in pixels)
Definition WriterBase.h:39
int video_bit_rate
The bit rate of the video stream (in bytes)
Definition WriterBase.h:43
bool has_audio
Determines if this file has an audio stream.
Definition WriterBase.h:35
std::string vcodec
The name of the video codec used to encode / decode the video stream.
Definition WriterBase.h:46
bool has_video
Determines if this file has a video stream.
Definition WriterBase.h:34
openshot::Fraction fps
Frames per second, as a fraction (i.e. 24/1 = 24 fps)
Definition WriterBase.h:42
openshot::Fraction video_timebase
The video timebase determines how long each frame stays on the screen.
Definition WriterBase.h:49
openshot::Fraction display_ratio
The ratio of width to height of the video stream (i.e. 640x480 has a ratio of 4/3)
Definition WriterBase.h:45
int width
The width of the video (in pixels)
Definition WriterBase.h:40
openshot::Fraction pixel_ratio
The pixel ratio of the video stream as a fraction (i.e. some pixels are not square)
Definition WriterBase.h:44