Update examples

examples/get_video_thumbnail.py

@@ -22,10 +22,12 @@ def generate_thumbnail(in_filename, out_filename, time, width):
             .input(in_filename, ss=time)
             .filter_('scale', width, -1)
             .output(out_filename, vframes=1)
-            .run(capture_stdout=True, capture_stderr=True, overwrite_output=True)
+            .overwrite_output()
+            .run(capture_stdout=True, capture_stderr=True)
         )
     except ffmpeg.Error as e:
         print(e.stderr.decode(), file=sys.stderr)
+        sys.exit(1)
 
 
 if __name__ == '__main__':

examples/requirements.txt

@@ -1,2 +1,4 @@
 ffmpeg-python
+gevent
 google-cloud-speech
+tqdm

examples/show_progress.py

@@ -0,0 +1,130 @@
+#!/usr/bin/env python
+from __future__ import unicode_literals, print_function
+from tqdm import tqdm
+import argparse
+import contextlib
+import ffmpeg
+import gevent
+import gevent.monkey; gevent.monkey.patch_all(thread=False)
+import os
+import shutil
+import socket
+import sys
+import tempfile
+import textwrap
+
+
+parser = argparse.ArgumentParser(description=textwrap.dedent('''\
+    Process video and report and show progress bar.
+
+    This is an example of using the ffmpeg `-progress` option with a
+    unix-domain socket to report progress in the form of a progress
+    bar.
+
+    The video processing simply consists of converting the video to
+    sepia colors, but the same pattern can be applied to other use
+    cases.
+'''))
+
+parser.add_argument('in_filename', help='Input filename')
+parser.add_argument('out_filename', help='Output filename')
+
+
+@contextlib.contextmanager
+def _tmpdir_scope():
+    tmpdir = tempfile.mkdtemp()
+    try:
+        yield tmpdir
+    finally:
+        shutil.rmtree(tmpdir)
+
+
+def _do_watch_progress(filename, sock, handler):
+    """Function to run in a separate gevent greenlet to read progress
+    events from a unix-domain socket."""
+    connection, client_address = sock.accept()
+    data = b''
+    try:
+        while True:
+            more_data = connection.recv(16)
+            if not more_data:
+                break
+            data += more_data
+            lines = data.split(b'\n')
+            for line in lines[:-1]:
+                line = line.decode()
+                parts = line.split('=')
+                key = parts[0] if len(parts) > 0 else None
+                value = parts[1] if len(parts) > 1 else None
+                handler(key, value)
+            data = lines[-1]
+    finally:
+        connection.close()
+
+
+@contextlib.contextmanager
+def _watch_progress(handler):
+    """Context manager for creating a unix-domain socket and listen for
+    ffmpeg progress events.
+
+    The socket filename is yielded from the context manager and the
+    socket is closed when the context manager is exited.
+
+    Args:
+        handler: a function to be called when progress events are
+            received; receives a ``key`` argument and ``value``
+            argument. (The example ``show_progress`` below uses tqdm)
+
+    Yields:
+        socket_filename: the name of the socket file.
+    """
+    with _tmpdir_scope() as tmpdir:
+        socket_filename = os.path.join(tmpdir, 'sock')
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        with contextlib.closing(sock):
+            sock.bind(socket_filename)
+            sock.listen(1)
+            child = gevent.spawn(_do_watch_progress, socket_filename, sock, handler)
+            try:
+                yield socket_filename
+            except:
+                gevent.kill(child)
+                raise
+
+
+
+@contextlib.contextmanager
+def show_progress(total_duration):
+    """Create a unix-domain socket to watch progress and render tqdm
+    progress bar."""
+    with tqdm(total=round(total_duration, 2)) as bar:
+        def handler(key, value):
+            if key == 'out_time_ms':
+                time = round(float(value) / 1000000., 2)
+                bar.update(time - bar.n)
+            elif key == 'progress' and value == 'end':
+                bar.update(bar.total - bar.n)
+        with _watch_progress(handler) as socket_filename:
+            yield socket_filename
+
+
+if __name__ == '__main__':
+    args = parser.parse_args()
+    total_duration = float(ffmpeg.probe(args.in_filename)['format']['duration'])
+
+    with show_progress(total_duration) as socket_filename:
+        # See https://ffmpeg.org/ffmpeg-filters.html#Examples-44
+        sepia_values = [.393, .769, .189, 0, .349, .686, .168, 0, .272, .534, .131]
+        try:
+            (ffmpeg
+                .input(args.in_filename)
+                .colorchannelmixer(*sepia_values)
+                .output(args.out_filename)
+                .global_args('-progress', 'unix://{}'.format(socket_filename))
+                .overwrite_output()
+                .run(capture_stdout=True, capture_stderr=True)
+            )
+        except ffmpeg.Error as e:
+            print(e.stderr, file=sys.stderr)
+            sys.exit(1)
+

examples/transcribe.py

@@ -1,13 +1,11 @@
 #!/usr/bin/env python
-from __future__ import unicode_literals
-
+from __future__ import unicode_literals, print_function
 from google.cloud import speech
 from google.cloud.speech import enums
 from google.cloud.speech import types
 import argparse
 import ffmpeg
 import logging
-import subprocess
 import sys
 
 
@@ -21,21 +19,17 @@ parser.add_argument('in_filename', help='Input filename (`-` for stdin)')
 
 
 def decode_audio(in_filename, **input_kwargs):
-    p = subprocess.Popen(
-        (ffmpeg
+    try:
+        out, err = (ffmpeg
             .input(in_filename, **input_kwargs)
             .output('-', format='s16le', acodec='pcm_s16le', ac=1, ar='16k')
             .overwrite_output()
-            .compile()
-        ),
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE
-    )
-    out = p.communicate()
-    if p.returncode != 0:
-        sys.stderr.write(out[1])
+            .run(capture_stdout=True, capture_stderr=True)
+        )
+    except ffmpeg.Error as e:
+        print(e.stderr, file=sys.stderr)
         sys.exit(1)
-    return out[0]
+    return out
 
 
 def get_transcripts(audio_data):

examples/video_info.py

@@ -11,15 +11,21 @@ parser.add_argument('in_filename', help='Input filename')
 
 if __name__ == '__main__':
     args = parser.parse_args()
-    probe = ffmpeg.probe(args.in_filename)
-    video_info = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
-    if video_info is None:
+
+    try:
+        probe = ffmpeg.probe(args.in_filename)
+    except ffmpeg.Error as e:
+        print(e.stderr, file=sys.stderr)
+        sys.exit(1)
+
+    video_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
+    if video_stream is None:
         print('No video stream found', file=sys.stderr)
         sys.exit(1)
 
-    width = int(video_info['width'])
-    height = int(video_info['height'])
-    num_frames = int(video_info['nb_frames'])
+    width = int(video_stream['width'])
+    height = int(video_stream['height'])
+    num_frames = int(video_stream['nb_frames'])
     print('width: {}'.format(width))
     print('height: {}'.format(height))
     print('num_frames: {}'.format(num_frames))