probe: functionalize

Author: scivision

README.md

@@ -9,23 +9,18 @@ Examples of Python asyncio.subprocess with FFmpeg and also traditional synchrono
 Both synchronous (traditional for loop) and asynchronous pipeline are demonstrated.
 They call FFprobe executable to return JSON formatted metadata.
 
-### probe_sync.py
-
-retrieve file metadata synchronously.
-
-### probe_coroutine.py
-
-retrieve file metadata in an asynchronous pipeline (asyncio generator) using Python `asyncio` coroutine event loop.
+* probe_sync.py: retrieve file metadata synchronously.
+* probe_coroutine.py: retrieve file metadata in asynchronous pipeline or list using Python `asyncio` coroutines.
 
 ## FFplay
 
-Test ingasynchronous techniques with video playback makes some effects obvious.
+Testing asynchronous techniques with video playback makes some effects obvious.
 The FFplay asyncio example is more advanced than the FFprobe example.
 In the FFprobe example, the lazy asyncio generator produces metadata concurrently as fast as it's requested.
 There is no resource throttling in the FFprobe example, so the CPU could become overwhelmed with context switching.
 
 The FFplay example in contrast is an example of a task using resource throttling via asyncio.Queue.
-The queueing could also be implemented for FFprobe style task if desired.
+The queuing could also be implemented for FFprobe style task if desired.
 However, the rationale employed is that the FFprobe task is overall lightweight, and thus other parts of the pipeline inherently limit resource utilization.
 If the FFprobe task was in an asyncio.gather() algorithm, resource utilization could get too high.
 Thus we have a "win-win" by using asyncio generator for FFprobe--the throttling comes implicitly from other parts of the pipeline.

play_coroutine.py

@@ -10,9 +10,7 @@
     p = ArgumentParser(description="Plays media files asynchronously with 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="+",
+        "-suffix", help="file suffixes of desired media file types", nargs="+",
     )
     P = p.parse_args()
 

probe_coroutine.py

@@ -1,7 +1,6 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 """
-3x to 4x speedup over ffprobe_sync on Linux
-10% speedup on Windows over ffprobe_sync, even with virus monitor disabled.
+~ 4x speedup over ffprobe_sync
 """
 import time
 from argparse import ArgumentParser
@@ -14,19 +13,16 @@
     p = ArgumentParser(description="Get media metadata asynchronously with FFprobe")
     p.add_argument("path", help="directory where media files are kept")
     p.add_argument(
-        "-suffix",
-        help="file suffixes of desired media file types",
-        nargs="+",
-        default=[".mp3", ".mp4", ".avi", ".ogv", ".ogg"],
+        "-suffix", help="file suffixes of desired media file types", nargs="+",
     )
     P = p.parse_args()
 
     tic = time.monotonic()
-    # emits results as each future is completed
+    # %% emits results as each future is completed
     runner(probe.get_meta, P.path, P.suffix)
-    print("ffprobe asyncio.as_completed: {:.3f} seconds".format(time.monotonic() - tic))
+    print(f"ffprobe asyncio.as_completed: {time.monotonic() - tic:.3f} seconds")
 
-    # approximately same wallclock time, but only gives results when all futures complete
+    # %% approximately same wallclock time, but only gives results when all futures complete
     tic = time.monotonic()
     runner(probe.get_meta_gather, P.path, P.suffix)
-    print("ffprobe asyncio.gather: {:.3f} seconds".format(time.monotonic() - tic))
+    print(f"ffprobe asyncio.gather: {time.monotonic() - tic:.3f} seconds")

probe_sync.py

@@ -1,30 +1,22 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import time
-from pathlib import Path
 from argparse import ArgumentParser
+
 import asyncioffmpeg.ffprobe as probe
+from asyncioffmpeg import get_videos
 
 
 if __name__ == "__main__":
     p = ArgumentParser(description="Get media metadata synchronously with FFprobe")
     p.add_argument("path", help="directory where media files are kept")
     p.add_argument(
-        "-suffix",
-        help="file suffixes of desired media file types",
-        nargs="+",
-        default=[".mp3", ".mp4", ".avi", ".ogv", ".ogg"],
+        "-suffix", help="file suffixes of desired media file types", nargs="+",
     )
     P = p.parse_args()
 
     tic = time.monotonic()
-    path = Path(P.path).expanduser()
-    if not path.is_dir():
-        raise FileNotFoundError(f"{path} is not a directory")
-
-    flist = (f for f in path.iterdir() if f.is_file() and f.suffix in P.suffix)
-
-    for f in flist:
+    for f in get_videos(P.path, P.suffix):
         meta = probe.ffprobe_sync(f)
         probe.print_meta(meta)
 
-    print("ffprobe sync: {:.3f} seconds".format(time.monotonic() - tic))
+    print(f"ffprobe sync: {time.monotonic() - tic:.3f} seconds")

src/asyncioffmpeg/ffprobe.py

@@ -10,18 +10,13 @@
 from pathlib import Path
 import shutil
 
+from . import get_videos
+
 FFPROBE = shutil.which("ffprobe")
 if not FFPROBE:
     raise ImportError("FFPROBE not found")
 
 
-def files2futures(path: Path, suffix: str) -> list:
-    path = Path(path).expanduser()
-    if not path.is_dir():
-        raise NotADirectoryError(path)
-    return [ffprobe(f) for f in path.iterdir() if f.is_file() and f.suffix in suffix]
-
-
 def print_meta(meta: typing.Dict[str, typing.Any]):
     fn = Path(meta["format"]["filename"])
     dur = float(meta["streams"][0]["duration"])
@@ -30,7 +25,7 @@ def print_meta(meta: typing.Dict[str, typing.Any]):
 
 async def get_meta_gather(path: Path, suffix: str) -> typing.List[typing.Dict[str, typing.Any]]:
     """ for comparison with asyncio.as_completed"""
-    futures = files2futures(path, suffix)
+    futures = [ffprobe(f) for f in get_videos(path, suffix)]
     metas = await asyncio.gather(*futures)
     for meta in metas:
         print_meta(meta)
@@ -39,7 +34,7 @@ async def get_meta_gather(path: Path, suffix: str) -> typing.List[typing.Dict[st
 
 
 async def get_meta(path: Path, suffix: str) -> typing.List[typing.Dict[str, typing.Any]]:
-    futures = files2futures(path, suffix)
+    futures = [ffprobe(f) for f in get_videos(path, suffix)]
     metas = []
     for file in asyncio.as_completed(futures):
         meta = await file
@@ -83,7 +78,7 @@ def ffprobe_sync(file: Path) -> typing.Dict[str, typing.Any]:
             "-show_format",
             str(file),
         ],
-        universal_newlines=True,
+        text=True,
     )
 
     return json.loads(meta)