initial

README.md

@@ -1 +1,43 @@
-CV2 Threaded Video Capture
+# CV2 Threaded Video Capture
+
+Not much to say here, it enables you to read an entire video or a number of frames from a video in an extra thread with some nice syntax.
+
+This project was initially part of my video synopsis project, wich is why the config dict() is required.
+
+### Full video
+```python
+from VideoReader import VideoReader
+import os
+
+fileName = "out.mp4"
+dirName = os.path.join(os.path.dirname(__file__), "generate test footage")
+
+config = {}
+config["inputPath"] = os.path.join(dirName, fileName)
+config["videoBufferLength"] = 100
+
+with VideoReader(config) as reader:
+    while not reader.videoEnded():
+        framenumber, frame = reader.pop()
+        print(framenumber)
+```
+
+### Selection of Frames
+```python
+from VideoReader import VideoReader
+import os
+
+fileName = "out.mp4"
+dirName = os.path.join(os.path.dirname(__file__), "generate test footage")
+
+config = {}
+config["inputPath"] = os.path.join(dirName, fileName)
+config["videoBufferLength"] = 100
+
+frameList = list(range(100, 500))
+
+with VideoReader(config, frameList) as reader:
+    while not reader.videoEnded():
+        framenumber, frame = reader.pop()
+        print(framenumber)
+```

VideoReader.py

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+from queue import Queue
+
+import cv2
+import threading
+import os
+
+class VideoReader:
+    listOfFrames = None
+    w = None
+    h = None
+
+    def __init__(self, config, setOfFrames=None):
+        videoPath = config["inputPath"]
+        self.videoPath = videoPath
+        
+        if videoPath is None:
+            raise Exception("VideoReader:: Video reader needs a videoPath!")
+        if not os.path.exists(videoPath):
+            raise Exception("VideoReader:: Provided video path does not exist")
+
+        self.lastFrame = 0
+        # buffer data struct:
+        # buffer = Queue([(frameNumber, frame), ])
+        self.buffer = Queue(config["videoBufferLength"])
+        self.vc = cv2.VideoCapture(videoPath)
+        self.stopped = False
+        self.getWH()
+        self.calcFPS()
+        self.calcLength()
+        self.calcStartTime()
+        if setOfFrames is not None:
+            self.listOfFrames = sorted(setOfFrames)
+        
+    def __enter__(self):
+        self.fillBuffer()
+        return self
+
+    def __exit__(self, type, value, traceback):
+        self.stop()
+
+    def stop(self):
+        self.thread.join()
+        self.vc.release()
+
+    def pop(self):
+        return self.buffer.get(block=True)
+
+    def fillBuffer(self, listOfFrames=None):
+        self.endFrame = int(self.vc.get(cv2.CAP_PROP_FRAME_COUNT))
+        if listOfFrames is not None:
+            self.listOfFrames = listOfFrames
+
+        if self.listOfFrames is not None:
+            self.thread = threading.Thread(
+                target=self.readFramesByList, args=())
+        else:
+            self.thread = threading.Thread(target=self.readFrames, args=())
+        self.thread.start()
+
+    def readFrames(self):
+        '''Reads video from start to finish'''
+        while self.lastFrame < self.endFrame:
+            res, frame = self.vc.read()
+            if res:
+                self.buffer.put((self.lastFrame, frame))
+            self.lastFrame += 1
+
+        self.stopped = True
+
+    def readFramesByList(self):
+        '''Reads all frames from a list of frame numbers'''
+        self.vc.set(1, self.listOfFrames[0])
+        self.lastFrame = self.listOfFrames[0]
+        self.endFrame = self.listOfFrames[-1]
+
+        while self.lastFrame < self.endFrame:
+            if self.lastFrame in self.listOfFrames:
+                res, frame = self.vc.read()
+                if res:
+                    self.buffer.put((self.lastFrame, frame))
+                else:
+                    print("READING FRAMES IS FALSE")
+                # since the list is sorted the first element is always the lowest relevant framenumber
+                # [0,1,2,3,32,33,34,35,67,68,69]
+                self.listOfFrames.pop(0)
+                self.lastFrame += 1
+            else:
+                # if current Frame number is not in list of Frames, we can skip a few frames
+                self.vc.set(1, self.listOfFrames[0])
+                self.lastFrame = self.listOfFrames[0]
+
+        self.stopped = True
+
+    def videoEnded(self):
+        if self.stopped and self.buffer.empty():
+            return True
+        else:
+            return False
+
+    def calcFPS(self):
+        self.fps = self.vc.get(cv2.CAP_PROP_FPS)
+
+    def getFPS(self):
+        if self.fps is None:
+            self.calcFPS()
+        return self.fps
+
+    def calcLength(self):
+        fc = int(self.vc.get(cv2.CAP_PROP_FRAME_COUNT))
+        self.length = fc / self.getFPS()
+
+    def getLength(self):
+        if self.length is None:
+            self.calcLength()
+        return self.length
+
+    def calcStartTime(self):
+        starttime = os.stat(self.videoPath).st_mtime
+        length = self.getLength()
+        starttime = starttime - length
+        self.starttime = starttime
+
+    def getStartTime(self):
+        return self.starttime
+
+    def getWH(self):
+        '''get width and height'''
+        if self.w is None or self.h is None:
+            res, image = self.vc.read()
+            self.w = image.shape[1]
+            self.h = image.shape[0]
+        return (self.w, self.h)

test.py

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+from VideoReader import VideoReader
+import os
+
+fileName = "out.mp4"
+dirName = os.path.join(os.path.dirname(__file__), "generate test footage")
+
+config = {}
+config["inputPath"] = os.path.join(dirName, fileName)
+config["videoBufferLength"] = 100
+
+with VideoReader(config) as reader:
+    while not reader.videoEnded():
+        framenumber, frame = reader.pop()
+        print(framenumber)