OpenShot Library | libopenshot  0.2.7
DummyReader.cpp
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1 /**
2  * @file
3  * @brief Source file for DummyReader class
4  * @author Jonathan Thomas <jonathan@openshot.org>
5  *
6  * @ref License
7  */
8 
9 /* LICENSE
10  *
11  * Copyright (c) 2008-2019 OpenShot Studios, LLC
12  * <http://www.openshotstudios.com/>. This file is part of
13  * OpenShot Library (libopenshot), an open-source project dedicated to
14  * delivering high quality video editing and animation solutions to the
15  * world. For more information visit <http://www.openshot.org/>.
16  *
17  * OpenShot Library (libopenshot) is free software: you can redistribute it
18  * and/or modify it under the terms of the GNU Lesser General Public License
19  * as published by the Free Software Foundation, either version 3 of the
20  * License, or (at your option) any later version.
21  *
22  * OpenShot Library (libopenshot) is distributed in the hope that it will be
23  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25  * GNU Lesser General Public License for more details.
26  *
27  * You should have received a copy of the GNU Lesser General Public License
28  * along with OpenShot Library. If not, see <http://www.gnu.org/licenses/>.
29  */
30 
31 #include "DummyReader.h"
32 #include "Exceptions.h"
33 
34 using namespace openshot;
35 
36 // Initialize variables used by constructor
37 void DummyReader::init(Fraction fps, int width, int height, int sample_rate, int channels, float duration) {
38  // Set key info settings
39  info.has_audio = false;
40  info.has_video = true;
41  info.file_size = width * height * sizeof(int);
42  info.vcodec = "raw";
43  info.fps = fps;
44  info.width = width;
45  info.height = height;
46  info.sample_rate = sample_rate;
47  info.channels = channels;
48  info.duration = duration;
49  info.video_length = duration * fps.ToFloat();
50  info.pixel_ratio.num = 1;
51  info.pixel_ratio.den = 1;
53  info.acodec = "raw";
54 
55  // Calculate the DAR (display aspect ratio)
57 
58  // Reduce size fraction
59  size.Reduce();
60 
61  // Set the ratio based on the reduced fraction
62  info.display_ratio.num = size.num;
63  info.display_ratio.den = size.den;
64 }
65 
66 // Blank constructor for DummyReader, with default settings.
67 DummyReader::DummyReader() : dummy_cache(NULL), is_open(false) {
68 
69  // Initialize important variables
70  init(Fraction(24,1), 1280, 768, 44100, 2, 30.0);
71 }
72 
73 // Constructor for DummyReader. Pass a framerate and samplerate.
74 DummyReader::DummyReader(Fraction fps, int width, int height, int sample_rate, int channels, float duration) : dummy_cache(NULL), is_open(false) {
75 
76  // Initialize important variables
77  init(fps, width, height, sample_rate, channels, duration);
78 }
79 
80 // Constructor which also takes a cache object
81 DummyReader::DummyReader(Fraction fps, int width, int height, int sample_rate, int channels, float duration, CacheBase* cache) : is_open(false) {
82 
83  // Initialize important variables
84  init(fps, width, height, sample_rate, channels, duration);
85 
86  // Set cache object
87  dummy_cache = (CacheBase*) cache;
88 }
89 
91 }
92 
93 // Open image file
95 {
96  // Open reader if not already open
97  if (!is_open)
98  {
99  // Create or get frame object
100  image_frame = std::make_shared<Frame>(1, info.width, info.height, "#000000", info.sample_rate, info.channels);
101 
102  // Mark as "open"
103  is_open = true;
104  }
105 }
106 
107 // Close image file
109 {
110  // Close all objects, if reader is 'open'
111  if (is_open)
112  {
113  // Mark as "closed"
114  is_open = false;
115  }
116 }
117 
118 // Get an openshot::Frame object for a specific frame number of this reader. It is either a blank frame
119 // or a custom frame added with passing a Cache object to the constructor.
120 std::shared_ptr<Frame> DummyReader::GetFrame(int64_t requested_frame)
121 {
122  // Check for open reader (or throw exception)
123  if (!is_open)
124  throw ReaderClosed("The ImageReader is closed. Call Open() before calling this method.", "dummy");
125 
126  int dummy_cache_count = 0;
127  if (dummy_cache) {
128  dummy_cache_count = dummy_cache->Count();
129  }
130 
131  if (dummy_cache_count == 0 && image_frame) {
132  // Create a scoped lock, allowing only a single thread to run the following code at one time
133  const GenericScopedLock<CriticalSection> lock(getFrameCriticalSection);
134 
135  // Always return same frame (regardless of which frame number was requested)
136  image_frame->number = requested_frame;
137  return image_frame;
138 
139  } else if (dummy_cache_count > 0) {
140  // Create a scoped lock, allowing only a single thread to run the following code at one time
141  const GenericScopedLock<CriticalSection> lock(getFrameCriticalSection);
142 
143  // Get a frame from the dummy cache
144  std::shared_ptr<openshot::Frame> f = dummy_cache->GetFrame(requested_frame);
145  if (f) {
146  // return frame from cache (if found)
147  return f;
148  } else {
149  // No cached frame found
150  throw InvalidFile("Requested frame not found. You can only access Frame numbers that exist in the Cache object.", "dummy");
151  }
152  }
153  else
154  // no frame loaded
155  throw InvalidFile("No frame could be created from this type of file.", "dummy");
156 }
157 
158 // Generate JSON string of this object
159 std::string DummyReader::Json() const {
160 
161  // Return formatted string
162  return JsonValue().toStyledString();
163 }
164 
165 // Generate Json::Value for this object
166 Json::Value DummyReader::JsonValue() const {
167 
168  // Create root json object
169  Json::Value root = ReaderBase::JsonValue(); // get parent properties
170  root["type"] = "DummyReader";
171 
172  // return JsonValue
173  return root;
174 }
175 
176 // Load JSON string into this object
177 void DummyReader::SetJson(const std::string value) {
178 
179  // Parse JSON string into JSON objects
180  try
181  {
182  const Json::Value root = openshot::stringToJson(value);
183  // Set all values that match
184  SetJsonValue(root);
185  }
186  catch (const std::exception& e)
187  {
188  // Error parsing JSON (or missing keys)
189  throw InvalidJSON("JSON is invalid (missing keys or invalid data types)");
190  }
191 }
192 
193 // Load Json::Value into this object
194 void DummyReader::SetJsonValue(const Json::Value root) {
195 
196  // Set parent data
198 
199 }
Header file for DummyReader class.
Header file for all Exception classes.
All cache managers in libopenshot are based on this CacheBase class.
Definition: CacheBase.h:49
virtual int64_t Count()=0
Count the frames in the queue.
virtual std::shared_ptr< openshot::Frame > GetFrame(int64_t frame_number)=0
Get a frame from the cache.
DummyReader()
Blank constructor for DummyReader, with default settings.
Definition: DummyReader.cpp:67
std::shared_ptr< openshot::Frame > GetFrame(int64_t requested_frame) override
void SetJson(const std::string value) override
Load JSON string into this object.
Json::Value JsonValue() const override
Generate Json::Value for this object.
std::string Json() const override
Generate JSON string of this object.
void Open() override
Open File - which is called by the constructor automatically.
Definition: DummyReader.cpp:94
void Close() override
Close File.
void SetJsonValue(const Json::Value root) override
Load Json::Value into this object.
This class represents a fraction.
Definition: Fraction.h:48
int num
Numerator for the fraction.
Definition: Fraction.h:50
float ToFloat()
Return this fraction as a float (i.e. 1/2 = 0.5)
Definition: Fraction.cpp:54
Fraction Reciprocal() const
Return the reciprocal as a Fraction.
Definition: Fraction.cpp:94
int den
Denominator for the fraction.
Definition: Fraction.h:51
Exception for files that can not be found or opened.
Definition: Exceptions.h:174
Exception for invalid JSON.
Definition: Exceptions.h:206
juce::CriticalSection getFrameCriticalSection
Section lock for multiple threads.
Definition: ReaderBase.h:101
openshot::ReaderInfo info
Information about the current media file.
Definition: ReaderBase.h:111
virtual void SetJsonValue(const Json::Value root)=0
Load Json::Value into this object.
Definition: ReaderBase.cpp:171
virtual Json::Value JsonValue() const =0
Generate Json::Value for this object.
Definition: ReaderBase.cpp:116
Exception when a reader is closed, and a frame is requested.
Definition: Exceptions.h:338
This namespace is the default namespace for all code in the openshot library.
Definition: Compressor.h:47
const Json::Value stringToJson(const std::string value)
Definition: Json.cpp:34
float duration
Length of time (in seconds)
Definition: ReaderBase.h:65
int width
The width of the video (in pixesl)
Definition: ReaderBase.h:68
int channels
The number of audio channels used in the audio stream.
Definition: ReaderBase.h:83
openshot::Fraction fps
Frames per second, as a fraction (i.e. 24/1 = 24 fps)
Definition: ReaderBase.h:70
openshot::Fraction display_ratio
The ratio of width to height of the video stream (i.e. 640x480 has a ratio of 4/3)
Definition: ReaderBase.h:73
int height
The height of the video (in pixels)
Definition: ReaderBase.h:67
int64_t video_length
The number of frames in the video stream.
Definition: ReaderBase.h:75
std::string acodec
The name of the audio codec used to encode / decode the video stream.
Definition: ReaderBase.h:80
std::string vcodec
The name of the video codec used to encode / decode the video stream.
Definition: ReaderBase.h:74
openshot::Fraction pixel_ratio
The pixel ratio of the video stream as a fraction (i.e. some pixels are not square)
Definition: ReaderBase.h:72
bool has_video
Determines if this file has a video stream.
Definition: ReaderBase.h:62
bool has_audio
Determines if this file has an audio stream.
Definition: ReaderBase.h:63
openshot::Fraction video_timebase
The video timebase determines how long each frame stays on the screen.
Definition: ReaderBase.h:77
int sample_rate
The number of audio samples per second (44100 is a common sample rate)
Definition: ReaderBase.h:82
int64_t file_size
Size of file (in bytes)
Definition: ReaderBase.h:66