'Twilio TwiML Connect bidirectional synchronous stream
I am trying to make a outgoing call from my twilio account/number to a PSTN mobile number.I am using this TwiML <Response> <Connect><Stream url="{ngrok_url}"/></Connect><Response>
With this I am able to recieve and play incoming audio from PSTN mobile phone however
I am unable to send outgoing audio to PSTN mobile phone.Here is the main websocket function which handles incoming audio and tries to
send outgoing packet in response via function "sendremotemediatotwilio"
async def websocket_rpc_endpoint(ws: WebSocket):
# A lot of messages will be sent rapidly. We'll stop showing after the first one.
global output_queue
inbuffer = bytearray(b'')
inbound_chunks_started = False
latest_inbound_timestamp = 0
BUFFER_SIZE = frames_per_buffer
await ws.accept()
while True:
data = await ws.receive_json()
# Using the event type you can determine what type of message you are receiving
if data['event'] == "connected":
print("Connected Message received: {}".format(data))
if data['event'] == "start":
print("Start Message received: {}".format(data))
if data['event'] == "media":
# print("Media message: {}".format(data))
media = data['media']
chunk = base64.b64decode(media['payload'])
# print("Payload is: {}".format(payload))
if media['track'] == 'inbound':
# fills in silence if there have been dropped packets
if inbound_chunks_started:
if latest_inbound_timestamp + 20 < int(media['timestamp']):
bytes_to_fill = 8 * (int(media['timestamp']) - (latest_inbound_timestamp + 20))
# NOTE: 0xff is silence for mulaw audio
# and there are 8 bytes per ms of data for our format (8 bit, 8000 Hz)
inbuffer.extend(b'\xff' * bytes_to_fill)
else:
# make it known that inbound chunks have started arriving
inbound_chunks_started = True
latest_inbound_timestamp = int(media['timestamp'])
latest_inbound_timestamp = int(media['timestamp'])
# extend the inbound audio buffer with data
inbuffer.extend(chunk)
while len(inbuffer) >= BUFFER_SIZE:
asinbound = AudioSegment(inbuffer[:BUFFER_SIZE], sample_width=1, frame_rate=8000, channels=1)
# # print("That's {} bytes".format(len(chunk)))
# print("That's {} bytes".format(len(chunk)))
# print("Additional media messages from WebSocket are being suppressed....")
output_queue.put_nowait(base64.b64encode(asinbound.raw_data))
inbuffer = inbuffer[BUFFER_SIZE:]
await sendremotemediatotwilio(ws,media,data['streamSid'])
# print("Added data in queue")
if data['event'] == "closed":
print("Closed Message received: {}".format(data))
break
async def sendremotemediatotwilio(ws,media,streamSid):
global input_queue
# if input_queue.empty():
# await asyncio.sleep(1)
if not input_queue.empty():
base64_data = input_queue.get_nowait()
media_data = {
"event": "media",
"streamSid": streamSid,
"media": {
"payload": base64.b64encode(base64_data).decode('utf-8')
}
}
# media = json.dumps(media_data)
# print(f"media: {media}")
print("sending json")
await ws.send_json(media_data)
else:
# print("Queue is empty")
pass
Solution 1:[1]
I have resolved this issue. Now I can successfully send and recieve packets to and from PSTN mobile phones. The issue was in transcoding from pcmu to linear pcm. Once it was resolved the same code is working OK
@app.websocket("/twiliomedia")
async def websocket_rpc_endpoint(ws: WebSocket):
# A lot of messages will be sent rapidly. We'll stop showing after the first one.
global output_queue,pushdatainqueue
inbuffer = bytearray(b'')
inbound_chunks_started = False
latest_inbound_timestamp = 0
BUFFER_SIZE = frames_per_buffer
await ws.accept()
while True:
data = await ws.receive_json()
# print("Json data",data)
# if message is None:
# print("No message received...")
# continue
#
# # Messages are a JSON encoded string
# data = json.loads(message)
# Using the event type you can determine what type of message you are receiving
if data['event'] == "connected":
print("Connected Message received: {}".format(data))
if data['event'] == "start":
print("Start Message received: {}".format(data))
if data['event'] == "media":
# print("Media message: {}".format(data))
media = data['media']
chunk = base64.b64decode(media['payload'])
# print("Payload is: {}".format(payload))
if media['track'] == 'inbound':
# fills in silence if there have been dropped packets
if inbound_chunks_started:
if latest_inbound_timestamp + 20 < int(media['timestamp']):
bytes_to_fill = 8 * (int(media['timestamp']) - (latest_inbound_timestamp + 20))
# NOTE: 0xff is silence for mulaw audio
# and there are 8 bytes per ms of data for our format (8 bit, 8000 Hz)
inbuffer.extend(b'\xff' * bytes_to_fill)
else:
# make it known that inbound chunks have started arriving
inbound_chunks_started = True
pushdatainqueue = True
latest_inbound_timestamp = int(media['timestamp'])
latest_inbound_timestamp = int(media['timestamp'])
# extend the inbound audio buffer with data
inbuffer.extend(chunk)
while len(inbuffer) >= BUFFER_SIZE:
asinbound = AudioSegment(inbuffer[:BUFFER_SIZE], sample_width=1, frame_rate=8000, channels=1)
# # print("That's {} bytes".format(len(chunk)))
# print("That's {} bytes".format(len(chunk)))
# print("Additional media messages from WebSocket are being suppressed....")
output_queue.put_nowait(base64.b64encode(asinbound.raw_data))
inbuffer = inbuffer[BUFFER_SIZE:]
await sendremotemediatotwilio(ws, media, data['streamSid'])
# print("Added data in queue")
if data['event'] == "closed":
print("Closed Message received: {}".format(data))
break
async def sendremotemediatotwilio(ws, media, streamSid):
global input_queue
# if input_queue.empty():
# await asyncio.sleep(1)
if not input_queue.empty():
base64_data = input_queue.get_nowait()
media_data = {
"event": "media",
"streamSid": streamSid,
"media": {
"payload": base64.b64encode(base64_data).decode("utf-8")
# "payload": base64_data.decode("utf-8")
}
}
# media = json.dumps(media_data)
# print(f"media: {media}")
print("sending json")
await ws.send_json(media_data)
else:
# print("Queue is empty")
pass
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | SAURABH PANDEY |