normalization pre-pass almost done, ffmpeg output reading lacking proper termination

aux.py

@@ -1,9 +1,32 @@
 #! /bin/env python3
 # encoding: utf-8
 
+import queue
+import subprocess
+import sys
+import threading
+import time
+
+import over # FIXME
+
+# --------------------------------------------------
+
+def capture_output(stream, fifo):
+	while True:
+		chunk = stream.read1(100)
+		
+		if chunk:
+			fifo.put(chunk)
+		else:
+			break
+	
+	stream.close()
+
 class Command:
 	def __init__(self, sequence):
 		self.__dict__["sequence"] = list(sequence)
+		self.__dict__["thread"] = None
+		self.__dict__["fifo"] = None
 	
 	def __setattr__(self, name, value):
 		found = False
@@ -29,3 +52,76 @@ class Command:
 				out.append(str(item))
 		
 		return out
+	
+	def run(self, async=False, stderr=False):
+		"""
+		Executes the command in the current environment.
+		
+		async     return immediatelly, use poll_output to get output
+		stderr    capture stderr instead of stdout
+		"""
+		
+		self.__dict__["process"] = subprocess.Popen(self.dump(), stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=1)
+		self.__dict__["fifo"] = queue.Queue()
+		self.__dict__["thread"] = threading.Thread(
+			target=capture_output,
+			args=(self.process.stderr if stderr else self.process.stdout, self.fifo)
+		)
+		self.thread.daemon = True # thread dies with the program
+		self.thread.start()
+		
+		if not async:
+			buffer = []
+			probably_dead = False
+			
+			while True:
+				probably_dead = self.process.poll() is not None
+				
+				chunk = self.poll_output()
+				
+				if chunk:
+					buffer.append(chunk)
+				else:
+					time.sleep(0.01)
+				
+				if not chunk and self.process.poll() is not None and probably_dead:
+					break
+			
+			return b"".join(buffer)
+		
+		else:
+			return None
+	
+	def poll_output(self):
+		"""
+		Returns the output of a currently running process and clears the buffer.
+		
+		Returns None if no process is running.
+		
+		Blocking - always returns at least one char.
+		"""
+		
+		if self.fifo.empty():
+			return None
+		
+		else:
+			buffer = []
+			
+			while not self.fifo.empty():
+				buffer.append(self.fifo.get_nowait())
+			
+			return b"".join(buffer)
+	
+	@property
+	def running(self):
+		return self.process.poll() is None
+
+# --------------------------------------------------
+
+def parse_fps(raw):
+	if "/" in raw:
+		num, den = (int(x) for x in raw.split("/"))
+		
+		return float(num) / float(den)
+	
+	return float(raw)