* add asr online app

Author: lxowalle

projects/demo_asr_online/app.png

@@ -0,0 +1,10 @@
+id: app_asr_online
+name: ASR Online
+version: 1.0.0
+author: lxowalle
+icon: app.png
+desc: >-
+  Connecting to an ASR server built on Sherpa-ONNX to use online speech
+  recognition.
+files:
+  - app_asr_online.py

projects/demo_asr_online/app.yaml

@@ -0,0 +1,159 @@
+from wave import Error
+from maix import camera, display, app, time, image, audio
+from maix._maix.err import Err
+import asyncio, json, websockets
+import numpy as np
+
+STATUS_OK = 0
+STATUS_EXIT = 1
+STATUS_SCAN_QRCODE = 2
+STATUS_SHOW_ASR = 3
+
+class AsrOnlineClient:
+    def __init__(self, exit_event):
+        self.recorder = audio.Recorder(sample_rate=16000, channel=1)
+        self.recorder.volume(100)
+        self.audio_queue = asyncio.Queue()
+        self.result_queue = asyncio.Queue()
+        self.exit_event = exit_event
+        pass  
+
+    async def read_audio_queue(self):
+        while not app.need_exit():
+            indata, status = await self.audio_queue.get()
+            yield indata, status
+
+    async def read_asr_result(self):
+        while not app.need_exit():
+            res, status = await self.result_queue.get()
+            yield res, status
+
+    async def receive_results(self, socket):
+        last_message = ""
+        async for message in socket:
+            if message != "Done!":
+                if last_message != message:
+                    last_message = message
+
+                    if last_message:
+                        decode_message = last_message.encode().decode('unicode_escape')
+                        status = STATUS_OK if not app.need_exit() else STATUS_EXIT
+                        await self.result_queue.put((json.loads(decode_message), status))
+                        print("Received: %s" % decode_message)
+            else:
+                return last_message
+
+    async def record_audio(self):
+        while True:
+            data = self.recorder.record(50)
+            status = STATUS_OK if not app.need_exit() else STATUS_EXIT
+            await self.audio_queue.put((data, status))
+            await asyncio.sleep(0.005)
+
+    async def run(self, queues):
+        while not app.need_exit():
+            ip, port = await queues[0].get()
+            print(f'recv ip:{ip} port:{port}')
+            server_url = f"ws://{ip}:{port}"
+            try:
+                async with websockets.connect(server_url) as websocket:
+                    await queues[1].put('OK')
+                    self.receive_task = asyncio.create_task(self.receive_results(websocket))
+                    self.audio_task = asyncio.create_task(self.record_audio())
+                    print("Started! Please Speak")
+                    async for indata, status in self.read_audio_queue():
+                        if status == STATUS_EXIT:
+                            return
+                        samples_int16 = np.frombuffer(indata, dtype=np.int16)
+                        samples_float32 = samples_int16.astype(np.float32)
+                        samples_float32 = samples_float32 / 32768
+                        send_bytes = samples_float32.tobytes()
+                        await websocket.send(send_bytes)
+            except websockets.exceptions.ConnectionClosedError as e:
+                await queues[1].put('SCAN AGAIN')
+                print(f'websockets exception {e}')
+            except websockets.exceptions.WebSocketException as e:
+                await queues[1].put('SCAN AGAIN')
+                print(f'websockets exception {e}')
+            except Exception as e:
+                await queues[1].put('SCAN AGAIN')
+                print(f'exception {e}')
+
+async def ui(cam, disp, client, queues):
+    detector = image.QRCodeDetector()
+    status = 1  # 0, standby 1,scan qrcode 2,show the result of asr
+    err_msg = ''
+    ip = ''
+    port = 0
+    while not app.need_exit():
+        if status == 0:
+            msg = await queues[1].get()
+            if msg == 'OK':
+                status = 2
+            elif msg == 'SCAN AGAIN':
+                status = 1
+                err_msg = f'connect ws://{ip}:{port} failed!'
+        elif status == 1:
+            img = cam.read()
+            qrcodes = detector.detect(img)
+            if len(qrcodes) > 0:
+                payload = qrcodes[0].payload()
+                try:
+                    json_res = json.loads(payload)
+                    ip = json_res["ip"]
+                    port = int(json_res["port"])
+                    print(f'send ip:{ip} port:{port}')
+                    img.clear()
+                    img.draw_string(10, 10, f"connect to ws://{ip}:{port}..")
+                    disp.show(img)
+                    await queues[0].put((ip, port))
+                    status = 0
+                    continue
+                except Exception as e:
+                    print(f'Parse {payload} falied, except:{e}')
+                    continue
+            title = "Scan QRCode"
+            msg1='1. Prepare a json string generated QR code.'
+            msg2='the format of json: {"ip":"127.0.0.1","port":6006}'
+            msg3='2. Put the qrcode in the screen.'
+            img.draw_string(10, 10, title)
+            img.draw_string(10, 40, msg1)
+            img.draw_string(10, 70, msg2)
+            img.draw_string(10, 100, msg3)
+            img.draw_string(10, 130, err_msg, image.COLOR_RED)
+            disp.show(img)
+        else:
+            base_img = image.Image(480, 320)
+            base_img.draw_string(10, 10, "Please Speak..(Press the uesr key to exit)", font="sourcehansans")
+            disp.show(base_img)
+            try:
+                async for res, status in client.read_asr_result():
+                    if status == STATUS_EXIT:
+                        return
+                    print(f'res:{res}')
+                    img = base_img.copy()
+                    img.draw_string(10, 60, res['text'], image.COLOR_WHITE, font="sourcehansans")
+                    disp.show(img)
+            except:
+                print('something exit')
+                return
+
+
+async def main():
+    image.load_font("sourcehansans", "/maixapp/share/font/SourceHanSansCN-Regular.otf")
+    cam = camera.Camera(480, 320)
+    disp = display.Display()
+    qrcode_queues = [asyncio.Queue(), asyncio.Queue()]
+    exit_event = asyncio.Event()
+    client = AsrOnlineClient(exit_event)
+    
+    ui_task = asyncio.create_task(ui(cam, disp, client, qrcode_queues))
+    client_task = asyncio.create_task(client.run(qrcode_queues))
+    tasks = [ui_task, client_task]
+    try:
+        await asyncio.gather(*tasks)
+    except Exception as e:
+        print(f'Exception caught: {e}')
+
+if __name__ == '__main__':
+    asyncio.run(main())