Allow the use of SoX if ffmpeg is not available

Author: iskunk

gentle/resample.py

@@ -1,4 +1,5 @@
 import os
+import shutil
 import subprocess
 import tempfile
 
@@ -8,11 +9,9 @@
 from .util.paths import get_binary
 
 FFMPEG = get_binary("ffmpeg")
+SOX = get_binary("sox")
 
-def resample(infile, outfile, offset=None, duration=None):
-    if not os.path.isfile(infile):
-        raise IOError("Not a file: %s" % infile)
-
+def resample_ffmpeg(infile, outfile, offset=None, duration=None):
     '''
     Use FFMPEG to convert a media file to a wav file sampled at 8K
     '''
@@ -38,6 +37,42 @@ def resample(infile, outfile, offset=None, duration=None):
     ]
     return subprocess.call(cmd)
 
+def resample_sox(infile, outfile, offset=None, duration=None):
+    '''
+    Use SoX to convert a media file to a wav file sampled at 8K
+    '''
+    if offset is None and duration is None:
+        trim = []
+    else:
+        if offset is None:
+            offset = 0
+        trim = ['trim', str(offset)]
+        if duration is not None:
+            trim += [str(duration)]
+
+    cmd = [
+        SOX,
+        '--clobber',
+        '-q',
+        '-V1',
+        infile,
+        '-b', '16',
+        '-c', '1',
+        '-e', 'signed-integer',
+        '-r', '8000',
+        '-L',
+        outfile
+    ] + trim
+    return subprocess.call(cmd)
+
+def resample(infile, outfile, offset=None, duration=None):
+    if not os.path.isfile(infile):
+        raise IOError("Not a file: %s" % infile)
+    if shutil.which(FFMPEG):
+        return resample_ffmpeg(infile, outfile, offset, duration)
+    else:
+        return resample_sox(infile, outfile, offset, duration)
+
 @contextmanager
 def resampled(infile, offset=None, duration=None):
     with tempfile.NamedTemporaryFile(suffix='.wav') as fp: