Add comments for config options.

Some folks were tripping up on this.

Author: Jerjou Cheng

speech/api/speech_async_grpc.py

@@ -59,8 +59,12 @@ def main(input_uri, encoding, sample_rate):
     # https://github.com/googleapis/googleapis/blob/master/google/cloud/speech/v1beta1/cloud_speech.proto
     response = service.AsyncRecognize(cloud_speech_pb2.AsyncRecognizeRequest(
         config=cloud_speech_pb2.RecognitionConfig(
-            encoding=encoding,
-            sample_rate=sample_rate,
+            # There are a bunch of config options you can specify. See
+            # https://g.co/cloud/speech/reference/rpc/google.cloud.speech.v1beta1#google.cloud.speech.v1beta1.RecognitionConfig  # noqa
+            # for the full list.
+            encoding=encoding,  # one of LINEAR16, FLAC, MULAW, AMR, AMR_WB
+            sample_rate=sample_rate,  # the rate in hertz
+            language_code='en-US',  # a BCP-47 language tag
         ),
         audio=cloud_speech_pb2.RecognitionAudio(
             uri=input_uri,

speech/api/speech_async_rest.py

@@ -57,8 +57,12 @@ def main(speech_file):
     service_request = service.speech().asyncrecognize(
         body={
             'config': {
-                'encoding': 'LINEAR16',
-                'sampleRate': 16000
+                # There are a bunch of config options you can specify. See
+                # https://cloud.google.com/speech/reference/rest/Shared.Types/RecognitionConfig  # noqa
+                # for the full list.
+                'encoding': 'LINEAR16',  # raw 16-bit signed LE samples
+                'sampleRate': 16000,  # 16 khz
+                'languageCode': 'en-US',  # a BCP-47 language tag
             },
             'audio': {
                 'content': speech_content.decode('UTF-8')

speech/api/speech_grpc.py

@@ -56,8 +56,12 @@ def main(input_uri, encoding, sample_rate):
     # https://github.com/googleapis/googleapis/blob/master/google/cloud/speech/v1beta1/cloud_speech.proto
     response = service.SyncRecognize(cloud_speech.SyncRecognizeRequest(
         config=cloud_speech.RecognitionConfig(
-            encoding=encoding,
-            sample_rate=sample_rate,
+            # There are a bunch of config options you can specify. See
+            # https://g.co/cloud/speech/reference/rpc/google.cloud.speech.v1beta1#google.cloud.speech.v1beta1.RecognitionConfig  # noqa
+            # for the full list.
+            encoding=encoding,  # one of LINEAR16, FLAC, MULAW, AMR, AMR_WB
+            sample_rate=sample_rate,  # the rate in hertz
+            language_code='en-US',  # a BCP-47 language tag
         ),
         audio=cloud_speech.RecognitionAudio(
             uri=input_uri,

speech/api/speech_rest.py

@@ -60,8 +60,12 @@ def main(speech_file):
     service_request = service.speech().syncrecognize(
         body={
             'config': {
-                'encoding': 'LINEAR16',
-                'sampleRate': 16000
+                # There are a bunch of config options you can specify. See
+                # https://cloud.google.com/speech/reference/rest/Shared.Types/RecognitionConfig  # noqa
+                # for the full list.
+                'encoding': 'LINEAR16',  # raw 16-bit signed LE samples
+                'sampleRate': 16000,  # 16 khz
+                'languageCode': 'en-US',  # a BCP-47 language tag
             },
             'audio': {
                 'content': speech_content.decode('UTF-8')

speech/api/speech_streaming.py

@@ -83,13 +83,19 @@ def request_stream(stop_audio, channels=CHANNELS, rate=RATE, chunk=CHUNK):
     Args:
         stop_audio: A threading.Event object stops the recording when set.
         channels: How many audio channels to record.
-        rate: The sampling rate.
+        rate: The sampling rate in hertz.
         chunk: Buffer audio into chunks of this size before sending to the api.
     """
     # The initial request must contain metadata about the stream, so the
     # server knows how to interpret it.
     recognition_config = cloud_speech.RecognitionConfig(
-        encoding='LINEAR16', sample_rate=rate)
+        # There are a bunch of config options you can specify. See
+        # https://g.co/cloud/speech/reference/rpc/google.cloud.speech.v1beta1#google.cloud.speech.v1beta1.RecognitionConfig  # noqa
+        # for the full list.
+        encoding='LINEAR16',  # raw 16-bit signed LE samples
+        sample_rate=rate,  # the rate in hertz
+        language_code='en-US',  # a BCP-47 language tag
+    )
     streaming_config = cloud_speech.StreamingRecognitionConfig(
         config=recognition_config,
         # Note that setting interim_results to True means that you'll likely