refactored speechrecognition parser

simplifies issue diagnosis

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>

textract/parsers/mp3_parser.py

@@ -1 +1 @@
-from .sox import Parser
+from .speech_recog import Parser

textract/parsers/ogg_parser.py

@@ -1 +1 @@
-from .sox import Parser
+from .speech_recog import Parser

textract/parsers/speech_recog.py

@@ -0,0 +1,59 @@
+import speech_recognition as sr
+import os
+
+from .utils import ShellParser
+
+
+class Parser(ShellParser):
+    """
+    Extract text (i.e. speech) from an audio file, using SpeechRecognition.
+
+    Since SpeechRecognition expects a .wav file, with 1 channel,
+    the audio file has to be converted, via sox, if not compliant
+
+    Note: for testing, use -
+    http://www2.research.att.com/~ttsweb/tts/demo.php,
+    with Rich (US English) for best results
+    """
+
+    def extract(self, filename, **kwargs):
+        speech = ''
+
+        # convert to wav, if not already .wav
+        base, ext = os.path.splitext(filename)
+        if ext != '.wav':
+            temp_filename = self.convert_to_wav(filename)
+            try:
+                speech = self.extract(temp_filename, **kwargs)
+            finally:  # make sure temp_file is deleted
+                os.remove(temp_filename)
+        else:
+            r = sr.Recognizer()
+
+            with sr.WavFile(filename) as source:
+                audio = r.record(source)
+
+            try:
+                speech = r.recognize(audio)
+            except LookupError:  # audio is not understandable
+                speech = ''
+
+            # add a newline, to make output cleaner
+            speech += '\n'
+
+        return speech
+
+    def convert_to_wav(self, filename):
+        """
+        Uses sox cmdline tool, to convert audio file to .wav
+
+        Note: for testing, use -
+        http://www.text2speech.org/,
+        with American Male 2 for best results
+        """
+        command = (
+            'sox -G -c 1 "%(filename)s" {0}'
+        )
+        temp_filename = '{0}.wav'.format(self.temp_filename())
+        self.run(command.format(temp_filename) % locals())
+        return temp_filename

textract/parsers/wav_parser.py

@@ -1,30 +1 @@
-import speech_recognition as sr
-
-from .utils import BaseParser
-
-
-class Parser(BaseParser):
-    """
-    Extract text (i.e. speech) from an audio file, using SpeechRecognition.
-    SpeechRecognition expects a .wav file, with one channel
-    So the audio file has to be converted, if not compliant
-    Note: for testing, use -
-    http://www2.research.att.com/~ttsweb/tts/demo.php,
-    with Rich (US English) for best results
-    """
-
-    def extract(self, filename, **kwargs):
-        r = sr.Recognizer()
-
-        with sr.WavFile(filename) as source:
-            audio = r.record(source)
-
-        try:
-            speech = r.recognize(audio)
-        except LookupError:  # audio is not understandable
-            speech = ''
-
-        # add a newline, to make output cleaner
-        speech += '\n'
-
-        return speech
+from .speech_recog import Parser