simplify play threads examples

Author: scivision

README.md

@@ -31,13 +31,16 @@ If the FFprobe task was in an asyncio.gather() algorithm, resource utilization c
 Thus we have a "win-win" by using asyncio generator for FFprobe--the throttling comes implicitly from other parts of the pipeline.
 
 
-### play_threadpool.py
+### Threading
 
-Even though coroutines are more efficient in many applications, the syntax of `concurrent.futures.ThreadPoolExecutor` is perhaps the simplest possible way to spawn independent processes in a controlled fashion
+Even though coroutines are more efficient in many applications, the syntax of `concurrent.futures.ThreadPoolExecutor` is perhaps the simplest possible way to spawn independent processes in a controlled fashion.
 
-### play_coroutine.py
+* play_thread.py: use ThreadPoolExecutor without queue
+* play_thread_queue.py: use ThreadPoolExecutor with queue
 
-Use Python `asyncio` coroutine event loop to spawn processes.
+### Coroutine
+
+* play_coroutine.py: `asyncio` coroutine event loop to spawn processes.
 
 ### Fortran
 

play_coroutine.py

@@ -13,7 +13,6 @@
         "-suffix",
         help="file suffixes of desired media file types",
         nargs="+",
-        default=[".mp4", ".avi", ".ogv", ".wmv", ".flv", ".mov", ".ogg"],
     )
     P = p.parse_args()
 

play_queue.py

@@ -13,13 +13,7 @@
 
 
 def ffplay(filein: Path):
-
-    if not filein.is_file():
-        raise FileNotFoundError(filein)
-
-    cmd = [EXE, "-v", "warning", "-autoexit", str(filein)]
-
-    subprocess.check_call(cmd)
+    subprocess.check_call([EXE, "-v", "warning", "-autoexit", str(filein)])
 
 
 if __name__ == "__main__":

play_threadpool.py renamed to play_thread.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+from argparse import ArgumentParser
+import concurrent.futures
+import queue
+from pathlib import Path
+import shutil
+import subprocess
+
+from asyncioffmpeg import get_videos
+
+EXE = shutil.which("ffplay")
+if not EXE:
+    raise FileNotFoundError("ffplay")
+
+
+def ffplay(filein: Path):
+    subprocess.check_call([EXE, "-v", "warning", "-autoexit", str(filein)])
+
+
+def main(qin: queue.Queue):
+    with concurrent.futures.ThreadPoolExecutor(max_workers=2, thread_name_prefix="ffplay") as pool:
+        while not qin.empty():
+            pool.submit(ffplay, qin.get(timeout=1.0))
+            qin.task_done()
+
+
+if __name__ == "__main__":
+    p = ArgumentParser(description="Asynchronous playback with ThreadPool and FFplay")
+    p.add_argument("path", help="directory where media files are kept")
+    p.add_argument(
+        "-suffix", help="file suffixes of desired media file types", nargs="+",
+    )
+    P = p.parse_args()
+
+    flist = get_videos(P.path, P.suffix)
+    print("found", len(flist), "files in", P.path)
+
+    qin = queue.Queue()  # type: ignore
+    for fn in flist:
+        qin.put(fn)
+
+    main(qin)
+    qin.join()

play_thread_queue.py

@@ -3,8 +3,6 @@
 This is more effective than endless context switching for an overloaded CPU.
 """
 
-import queue
-import subprocess
 import asyncio
 from pathlib import Path
 import shutil
@@ -62,21 +60,3 @@ async def main(flist: Iterable[Path]):
         task.cancel()
 
     await asyncio.gather(*tasks, return_exceptions=True)
-
-
-def ffplay_sync(qin: queue.Queue):
-    """
-    Play media synchronously
-    """
-
-    while not qin.empty():
-        filein = qin.get(timeout=1.0)
-
-        cmd = [FFPLAY, "-v", "warning", "-autoexit", str(filein)]
-
-        ret = subprocess.run(cmd)
-
-        if ret.returncode != 0:
-            print(filein, "playback failure", cmd, file=sys.stderr)
-
-        qin.task_done()