Fixing sounddevice stream active state recovery and adding corresponding exceptions

src/lerobot/microphones/microphone.py

@@ -31,7 +31,9 @@ import soundfile as sf
 
 from lerobot.errors import (
     DeviceAlreadyConnectedError,
+    DeviceAlreadyRecordingError,
     DeviceNotConnectedError,
+    DeviceNotRecordingError,
 )
 from lerobot.microphones.configs import MicrophoneConfig
 from lerobot.utils.utils import capture_timestamp_utc
@@ -145,6 +147,7 @@ class Microphone:
 
         self.logs = {}
         self.is_connected = False
+        self.is_recording = False
 
     def connect(self) -> None:
         if self.is_connected:
@@ -261,6 +264,8 @@ class Microphone:
     def start_recording(self, output_file: str | None = None) -> None:
         if not self.is_connected:
             raise DeviceNotConnectedError(f"Microphone {self.microphone_index} is not connected.")
+        if self.is_recording:
+            raise DeviceAlreadyRecordingError(f"Microphone {self.microphone_index} is already recording.")
 
         self.read_queue = Queue()
         with self.read_queue.mutex:
@@ -283,13 +288,14 @@ class Microphone:
             self.record_thread.daemon = True
             self.record_thread.start()
 
+        self.is_recording = True
         self.stream.start()
 
     def stop_recording(self) -> None:
         if not self.is_connected:
             raise DeviceNotConnectedError(f"Microphone {self.microphone_index} is not connected.")
-
+        if not self.is_recording:
-        self.logs["stop_timestamp"] = capture_timestamp_utc()
+            raise DeviceNotRecordingError(f"Microphone {self.microphone_index} is not recording.")
 
         if self.record_thread is not None:
             # self.record_queue.join()
@@ -302,11 +308,15 @@ class Microphone:
             self.stream.stop()  # Wait for all buffers to be processed
             # Remark : stream.abort() flushes the buffers !
 
+        self.is_recording = False
+
+        self.logs["stop_timestamp"] = capture_timestamp_utc()
+
     def disconnect(self) -> None:
         if not self.is_connected:
             raise DeviceNotConnectedError(f"Microphone {self.microphone_index} is not connected.")
 
-        if self.stream.active:
+        if self.is_recording:
             self.stop_recording()
 
         self.stream.close()

src/lerobot/utils/errors.py

@@ -30,3 +30,22 @@ class DeviceAlreadyConnectedError(ConnectionError):
     ):
         self.message = message
         super().__init__(self.message)
+
+
+class DeviceNotRecordingError(Exception):
+    """Exception raised when the robot device is not recording."""
+
+    def __init__(self, message="This robot device is not recording. Try calling `start_recording()` first."):
+        self.message = message
+        super().__init__(self.message)
+
+
+class DeviceAlreadyRecordingError(Exception):
+    """Exception raised when the robot device is already recording."""
+
+    def __init__(
+        self,
+        message="This robot device is already recording. Try not calling `start_recording()` twice.",
+    ):
+        self.message = message
+        super().__init__(self.message)