Asyncio support async/await #200

ffmpeg/_run.py

@@ -7,6 +7,7 @@ import collections
 import copy
 import operator
 import subprocess
+import asyncio
 
 from ._ffmpeg import (
     input,
@@ -296,10 +297,44 @@ def run(
     return out, err
 
 
+@output_operator()
+async def run_asyncio(
+        stream_spec, cmd='ffmpeg', pipe_stdin=False, pipe_stdout=False, pipe_stderr=False,
+        quiet=False, overwrite_output=False):
+    """Asynchronously invoke ffmpeg in asyncio sync/await style and return coroutine.
+    Have the same possibilities as `run_async` call.
+
+    Args:
+        pipe_stdin: if True, connect pipe to subprocess stdin (to be
+            used with ``pipe:`` ffmpeg inputs).
+        pipe_stdout: if True, connect pipe to subprocess stdout (to be
+            used with ``pipe:`` ffmpeg outputs).
+        pipe_stderr: if True, connect pipe to subprocess stderr.
+        quiet: shorthand for setting ``capture_stdout`` and
+            ``capture_stderr``.
+
+    Returns:
+        A Process instance as a coroutine
+    """
+
+    args = compile(stream_spec, cmd, overwrite_output=overwrite_output)
+    stdin_stream = asyncio.subprocess.PIPE if pipe_stdin else None
+    stdout_stream = asyncio.subprocess.PIPE if pipe_stdout or quiet else None
+    stderr_stream = asyncio.subprocess.PIPE if pipe_stderr or quiet else None
+
+    return await asyncio.create_subprocess_exec(
+        *args,
+        stdin=stdin_stream,
+        stdout=stdout_stream,
+        stderr=stderr_stream
+    )
+
+
 __all__ = [
     'compile',
     'Error',
     'get_args',
     'run',
     'run_async',
+    'run_asyncio',
 ]

ffmpeg/tests/test_ffmpeg.py

@@ -1,4 +1,7 @@
 from __future__ import unicode_literals
+
+import asyncio
+
 from builtins import bytes
 from builtins import range
 from builtins import str
@@ -655,3 +658,31 @@ def test__probe__exception():
 def test__probe__extra_args():
     data = ffmpeg.probe(TEST_INPUT_FILE1, show_frames=None)
     assert set(data.keys()) == {'format', 'streams', 'frames'}
+
+
+def test_run_asyncio():
+    async def test_async():
+        process = await (
+            ffmpeg
+             .input(TEST_INPUT_FILE1)
+             .output('pipe:', format='rawvideo', pix_fmt='rgb24')['v']
+             .run_asyncio(pipe_stdout=True, quiet=False)
+        )
+
+        video_frame_size = 320 * 240 * 3  # Note: RGB24 == 3 bytes per pixel. 320x240 - video size
+
+        total_bytes = 0
+
+        while True:
+            frame_bytes = await process.stdout.read(video_frame_size)
+            if len(frame_bytes) == 0:
+                break
+            else:
+                total_bytes += len(frame_bytes)
+
+        await process.wait()
+
+        assert total_bytes == 48153600, 'Incorrect size of the output frames'
+
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(test_async())