Add split_silence example

examples/split_silence.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python
+from __future__ import unicode_literals
+
+import argparse
+import ffmpeg
+import logging
+import re
+import subprocess
+
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__file__)
+logger.setLevel(logging.INFO)
+
+DEFAULT_DURATION = 0.3
+DEFAULT_THRESHOLD = -60
+
+parser = argparse.ArgumentParser(description='Split media into separate chunks wherever silence occurs')
+parser.add_argument('in_filename', help='Input filename (`-` for stdin)')
+parser.add_argument('out_pattern', help='Output filename pattern (e.g. `out/chunk_%%04d.wav`)')
+parser.add_argument('--silence-threshold', default=DEFAULT_THRESHOLD, type=int, help='Silence threshold (in dB)')
+parser.add_argument('--silence-duration', default=DEFAULT_DURATION, type=float, help='Silence duration')
+parser.add_argument('--start-time', type=float, help='Start time (seconds)')
+parser.add_argument('--end-time', type=float, help='End time (seconds)')
+
+
+silence_start_re = re.compile(' silence_start: (?P<start>[0-9]+(\.?[0-9]*))$')
+silence_end_re = re.compile(' silence_end: (?P<end>[0-9]+(\.?[0-9]*)) ')
+total_duration_re = re.compile(
+    'size=[^ ]+ time=(?P<hours>[0-9]{2}):(?P<minutes>[0-9]{2}):(?P<seconds>[0-9\.]{5}) bitrate=')
+
+
+def get_chunk_times(in_filename, silence_threshold, silence_duration, start_time=None, end_time=None):
+    input_kwargs = {}
+    if start_time is not None:
+        input_kwargs['ss'] = start_time
+    else:
+        start_time = 0.
+    if end_time is not None:
+        input_kwargs['t'] = end_time - start_time
+
+    args = (ffmpeg
+        .input(in_filename, **input_kwargs)
+        .filter_('silencedetect', n='{}dB'.format(silence_threshold), d=silence_duration)
+        .output('-', format='null')
+        .get_args()
+    )
+    p = subprocess.Popen(['ffmpeg'] + args, stderr=subprocess.PIPE)
+    output = p.communicate()[1].decode('utf-8')
+    lines = output.splitlines()
+
+    # Chunks start when silence ends, and chunks end when silence starts.
+    chunk_starts = []
+    chunk_ends = []
+    for line in lines:
+        silence_start_match = silence_start_re.search(line)
+        silence_end_match = silence_end_re.search(line)
+        total_duration_match = total_duration_re.search(line)
+        if silence_start_match:
+            chunk_ends.append(float(silence_start_match.group('start')))
+            if len(chunk_starts) == 0:
+                # Started with non-silence.
+                chunk_starts.append(start_time or 0.)
+        elif silence_end_match:
+            chunk_starts.append(float(silence_end_match.group('end')))
+        elif total_duration_match:
+            hours = int(total_duration_match.group('hours'))
+            minutes = int(total_duration_match.group('minutes'))
+            seconds = float(total_duration_match.group('seconds'))
+            end_time = hours * 3600 + minutes * 60 + seconds
+
+    if len(chunk_starts) == 0:
+        # No silence found.
+        chunk_starts.append(start_time)
+
+    if len(chunk_starts) > len(chunk_ends):
+        # Finished with non-silence.
+        chunk_ends.append(end_time or 10000000.)
+
+    return list(zip(chunk_starts, chunk_ends))
+
+
+def split_audio(
+    in_filename,
+    out_pattern,
+    silence_threshold=DEFAULT_THRESHOLD,
+    silence_duration=DEFAULT_DURATION,
+    start_time=None,
+    end_time=None,
+):
+    chunk_times = get_chunk_times(in_filename, silence_threshold, silence_duration, start_time, end_time)
+    for i, (start_time, end_time) in enumerate(chunk_times):
+        time = end_time - start_time
+        out_filename = out_pattern % i
+        logger.info('{}: start={:.02f}, end={:.02f}, duration={:.02f}'.format(out_filename, start_time, end_time,
+            time))
+        subprocess.Popen(
+            (ffmpeg
+                .input(in_filename, ss=start_time, t=time)
+                .output(out_filename)
+                .overwrite_output()
+                .compile()
+            ),
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        ).communicate()
+
+
+if __name__ == '__main__':
+    args = parser.parse_args()
+    split_audio(**vars(args))