adding infinite streaming sample to samples folder, unlike indefinite…

…… [(#2161)](GoogleCloudPlatform/python-docs-samples#2161)

* adding infinite streaming sample to samples folder, unlike indefinite streaming, this sample uses result_end_time to calculate unfinalized audio, and to resend it to maintain context across into the next streaming request

* fixed some travis ci lint issues

* fixed some travis ci lint issues

* fixed some travis ci lint issues

* fixed some travis ci lint issues

google-cloud-speech/samples/microphone/transcribe_streaming_infinite.py

@@ -0,0 +1,294 @@
+#!/usr/bin/env python
+
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Google Cloud Speech API sample application using the streaming API.
+
+NOTE: This module requires the dependencies `pyaudio` and `termcolor`.
+To install using pip:
+
+    pip install pyaudio
+    pip install termcolor
+
+Example usage:
+    python transcribe_streaming_infinite.py
+"""
+
+# [START speech_transcribe_infinite_streaming]
+
+import time
+import re
+import sys
+
+# uses result_end_time currently only avaialble in v1p1beta, will be in v1 soon
+from google.cloud import speech_v1p1beta1 as speech
+import pyaudio
+from six.moves import queue
+
+# Audio recording parameters
+STREAMING_LIMIT = 10000
+SAMPLE_RATE = 16000
+CHUNK_SIZE = int(SAMPLE_RATE / 10)  # 100ms
+
+RED = '\033[0;31m'
+GREEN = '\033[0;32m'
+YELLOW = '\033[0;33m'
+
+
+def get_current_time():
+    """Return Current Time in MS."""
+
+    return int(round(time.time() * 1000))
+
+
+class ResumableMicrophoneStream:
+    """Opens a recording stream as a generator yielding the audio chunks."""
+
+    def __init__(self, rate, chunk_size):
+        self._rate = rate
+        self.chunk_size = chunk_size
+        self._num_channels = 1
+        self._buff = queue.Queue()
+        self.closed = True
+        self.start_time = get_current_time()
+        self.restart_counter = 0
+        self.audio_input = []
+        self.last_audio_input = []
+        self.result_end_time = 0
+        self.is_final_end_time = 0
+        self.final_request_end_time = 0
+        self.bridging_offset = 0
+        self.last_transcript_was_final = False
+        self.new_stream = True
+        self._audio_interface = pyaudio.PyAudio()
+        self._audio_stream = self._audio_interface.open(
+            format=pyaudio.paInt16,
+            channels=self._num_channels,
+            rate=self._rate,
+            input=True,
+            frames_per_buffer=self.chunk_size,
+            # Run the audio stream asynchronously to fill the buffer object.
+            # This is necessary so that the input device's buffer doesn't
+            # overflow while the calling thread makes network requests, etc.
+            stream_callback=self._fill_buffer,
+        )
+
+    def __enter__(self):
+
+        self.closed = False
+        return self
+
+    def __exit__(self, type, value, traceback):
+
+        self._audio_stream.stop_stream()
+        self._audio_stream.close()
+        self.closed = True
+        # Signal the generator to terminate so that the client's
+        # streaming_recognize method will not block the process termination.
+        self._buff.put(None)
+        self._audio_interface.terminate()
+
+    def _fill_buffer(self, in_data, *args, **kwargs):
+        """Continuously collect data from the audio stream, into the buffer."""
+
+        self._buff.put(in_data)
+        return None, pyaudio.paContinue
+
+    def generator(self):
+        """Stream Audio from microphone to API and to local buffer"""
+
+        while not self.closed:
+            data = []
+
+            if self.new_stream and self.last_audio_input:
+
+                chunk_time = STREAMING_LIMIT / len(self.last_audio_input)
+
+                if chunk_time != 0:
+
+                    if self.bridging_offset < 0:
+                        self.bridging_offset = 0
+
+                    if self.bridging_offset > self.final_request_end_time:
+                        self.bridging_offset = self.final_request_end_time
+
+                    chunks_from_ms = round((self.final_request_end_time -
+                                            self.bridging_offset) / chunk_time)
+
+                    self.bridging_offset = (round((
+                        len(self.last_audio_input) - chunks_from_ms)
+                                                  * chunk_time))
+
+                    for i in range(chunks_from_ms, len(self.last_audio_input)):
+                        data.append(self.last_audio_input[i])
+
+                self.new_stream = False
+
+            # Use a blocking get() to ensure there's at least one chunk of
+            # data, and stop iteration if the chunk is None, indicating the
+            # end of the audio stream.
+            chunk = self._buff.get()
+            self.audio_input.append(chunk)
+
+            if chunk is None:
+                return
+            data.append(chunk)
+            # Now consume whatever other data's still buffered.
+            while True:
+                try:
+                    chunk = self._buff.get(block=False)
+
+                    if chunk is None:
+                        return
+                    data.append(chunk)
+                    self.audio_input.append(chunk)
+
+                except queue.Empty:
+                    break
+
+            yield b''.join(data)
+
+
+def listen_print_loop(responses, stream):
+    """Iterates through server responses and prints them.
+
+    The responses passed is a generator that will block until a response
+    is provided by the server.
+
+    Each response may contain multiple results, and each result may contain
+    multiple alternatives; for details, see https://goo.gl/tjCPAU.  Here we
+    print only the transcription for the top alternative of the top result.
+
+    In this case, responses are provided for interim results as well. If the
+    response is an interim one, print a line feed at the end of it, to allow
+    the next result to overwrite it, until the response is a final one. For the
+    final one, print a newline to preserve the finalized transcription.
+    """
+
+    for response in responses:
+
+        if get_current_time() - stream.start_time > STREAMING_LIMIT:
+            stream.start_time = get_current_time()
+            break
+
+        if not response.results:
+            continue
+
+        result = response.results[0]
+
+        if not result.alternatives:
+            continue
+
+        transcript = result.alternatives[0].transcript
+
+        result_seconds = 0
+        result_nanos = 0
+
+        if result.result_end_time.seconds:
+            result_seconds = result.result_end_time.seconds
+
+        if result.result_end_time.nanos:
+            result_nanos = result.result_end_time.nanos
+
+        stream.result_end_time = int((result_seconds * 1000)
+                                     + (result_nanos / 1000000))
+
+        corrected_time = (stream.result_end_time - stream.bridging_offset
+                          + (STREAMING_LIMIT * stream.restart_counter))
+        # Display interim results, but with a carriage return at the end of the
+        # line, so subsequent lines will overwrite them.
+
+        if result.is_final:
+
+            sys.stdout.write(GREEN)
+            sys.stdout.write('\033[K')
+            sys.stdout.write(str(corrected_time) + ': ' + transcript + '\n')
+
+            stream.is_final_end_time = stream.result_end_time
+            stream.last_transcript_was_final = True
+
+            # Exit recognition if any of the transcribed phrases could be
+            # one of our keywords.
+            if re.search(r'\b(exit|quit)\b', transcript, re.I):
+                sys.stdout.write(YELLOW)
+                sys.stdout.write('Exiting...\n')
+                stream.closed = True
+                break
+
+        else:
+            sys.stdout.write(RED)
+            sys.stdout.write('\033[K')
+            sys.stdout.write(str(corrected_time) + ': ' + transcript + '\r')
+
+            stream.last_transcript_was_final = False
+
+
+def main():
+    """start bidirectional streaming from microphone input to speech API"""
+
+    client = speech.SpeechClient()
+    config = speech.types.RecognitionConfig(
+        encoding=speech.enums.RecognitionConfig.AudioEncoding.LINEAR16,
+        sample_rate_hertz=SAMPLE_RATE,
+        language_code='en-US',
+        max_alternatives=1)
+    streaming_config = speech.types.StreamingRecognitionConfig(
+        config=config,
+        interim_results=True)
+
+    mic_manager = ResumableMicrophoneStream(SAMPLE_RATE, CHUNK_SIZE)
+    print(mic_manager.chunk_size)
+    sys.stdout.write(YELLOW)
+    sys.stdout.write('\nListening, say "Quit" or "Exit" to stop.\n\n')
+    sys.stdout.write('End (ms)       Transcript Results/Status\n')
+    sys.stdout.write('=====================================================\n')
+
+    with mic_manager as stream:
+
+        while not stream.closed:
+            sys.stdout.write(YELLOW)
+            sys.stdout.write('\n' + str(
+                STREAMING_LIMIT * stream.restart_counter) + ': NEW REQUEST\n')
+
+            stream.audio_input = []
+            audio_generator = stream.generator()
+
+            requests = (speech.types.StreamingRecognizeRequest(
+                audio_content=content)for content in audio_generator)
+
+            responses = client.streaming_recognize(streaming_config,
+                                                   requests)
+
+            # Now, put the transcription responses to use.
+            listen_print_loop(responses, stream)
+
+            if stream.result_end_time > 0:
+                stream.final_request_end_time = stream.is_final_end_time
+            stream.result_end_time = 0
+            stream.last_audio_input = []
+            stream.last_audio_input = stream.audio_input
+            stream.audio_input = []
+            stream.restart_counter = stream.restart_counter + 1
+
+            if not stream.last_transcript_was_final:
+                sys.stdout.write('\n')
+            stream.new_stream = True
+
+
+if __name__ == '__main__':
+
+    main()
+
+# [END speech_transcribe_infinite_streaming]