better exception handling, soft task interruption, GUI stop button, GUI folder processing, better argument checks

src/progress_monitor.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Name: Video2X Upscale Progress Monitor
+Author: BrianPetkovsek
+Date Created: May 7, 2020
+Last Modified: May 7, 2020
+"""
+
+# built-in imports
+import contextlib
+import threading
+import time
+
+# third-party imports
+from tqdm import tqdm
+
+
+class ProgressMonitor(threading.Thread):
+    """ progress monitor
+
+    This class provides progress monitoring functionalities
+    by keeping track of the amount of frames in the input
+    directory and the output directory. This is originally
+    suggested by @ArmandBernard.
+    """
+
+    def __init__(self, upscaler, extracted_frames_directories):
+        threading.Thread.__init__(self)
+        self.upscaler = upscaler
+        self.extracted_frames_directories = extracted_frames_directories
+        self.running = False
+
+    def run(self):
+        self.running = True
+        
+        # get number of extracted frames
+        self.upscaler.total_frames = 0
+        for directory in self.extracted_frames_directories:
+            self.upscaler.total_frames += len([f for f in directory.iterdir() if str(f).lower().endswith(self.upscaler.image_format.lower())])
+
+        with tqdm(total=self.upscaler.total_frames, ascii=True, desc=_('Upscaling Progress')) as progress_bar:
+            # tqdm update method adds the value to the progress
+            # bar instead of setting the value. Therefore, a delta
+            # needs to be calculated.
+            previous_cycle_frames = 0
+            while self.running:
+
+                with contextlib.suppress(FileNotFoundError):
+                    self.upscaler.total_frames_upscaled = len([f for f in self.upscaler.upscaled_frames.iterdir() if str(f).lower().endswith(self.upscaler.image_format.lower())])
+
+                    # update progress bar
+                    delta = self.upscaler.total_frames_upscaled - previous_cycle_frames
+                    previous_cycle_frames = self.upscaler.total_frames_upscaled
+                    progress_bar.update(delta)
+
+                time.sleep(1)
+
+    def stop(self):
+        self.running = False
+        self.join()