dograh/api/services/pipecat/in_memory_buffers.py
Sabiha Khan ac01f7775e
Feat/enhanced timestamped transcript (#501)
* feat: add additional timestamps in call transcript optionally

* fi: timestamp precision to millisec instead of micro

* fix: address enhanced transcript review issues

* fix: non vad user turn timestamp
2026-07-07 14:47:43 +05:30

303 lines
12 KiB
Python

import asyncio
import io
import wave
from datetime import UTC, datetime
from typing import List, Optional
from loguru import logger
from api.services.pipecat.realtime_feedback_events import (
realtime_feedback_event_sort_key,
stamp_realtime_feedback_event,
)
from api.utils.transcript import generate_transcript_text as _generate_transcript_text
from pipecat.utils.enums import RealtimeFeedbackType
class InMemoryAudioBuffer:
"""Buffer audio data in memory during a call, then encode to WAV bytes on disconnect."""
def __init__(self, workflow_run_id: int, sample_rate: int, num_channels: int = 1):
self._workflow_run_id = workflow_run_id
self._sample_rate = sample_rate
self._num_channels = num_channels
self._chunks: List[bytes] = []
self._lock = asyncio.Lock()
self._total_size = 0
self._max_size = 100 * 1024 * 1024 # 100MB limit
async def append(self, pcm_data: bytes):
"""Append PCM audio data to the buffer."""
async with self._lock:
if self._total_size + len(pcm_data) > self._max_size:
logger.error(
f"Audio buffer size limit exceeded for workflow {self._workflow_run_id}. "
f"Current: {self._total_size}, Attempted to add: {len(pcm_data)}"
)
raise MemoryError("Audio buffer size limit exceeded")
self._chunks.append(pcm_data)
self._total_size += len(pcm_data)
logger.trace(
f"Appended {len(pcm_data)} bytes to audio buffer. Total size: {self._total_size}"
)
async def to_wav_bytes(self) -> bytes:
"""Encode the buffered PCM data as an in-memory WAV file."""
async with self._lock:
chunks = list(self._chunks)
def _encode() -> bytes:
wav_io = io.BytesIO()
with wave.open(wav_io, "wb") as wf:
wf.setnchannels(self._num_channels)
wf.setsampwidth(2) # 16-bit audio
wf.setframerate(self._sample_rate)
# Concatenate all chunks
for chunk in chunks:
wf.writeframes(chunk)
return wav_io.getvalue()
# Encoding is mostly memcpy but can touch ~100MB; keep it off the event loop
data = await asyncio.to_thread(_encode)
logger.info(
f"Encoded {self._total_size} bytes of audio to {len(data)} WAV bytes "
f"for workflow {self._workflow_run_id}"
)
return data
@property
def is_empty(self) -> bool:
"""Check if the buffer is empty."""
return len(self._chunks) == 0
@property
def size(self) -> int:
"""Get the total size of buffered data."""
return self._total_size
class InMemoryRecordingBuffers:
"""Holds the mixed recording plus aligned user and bot mono tracks."""
def __init__(self, workflow_run_id: int, sample_rate: int, num_channels: int = 1):
self.mixed = InMemoryAudioBuffer(
workflow_run_id=workflow_run_id,
sample_rate=sample_rate,
num_channels=num_channels,
)
self.user = InMemoryAudioBuffer(
workflow_run_id=workflow_run_id,
sample_rate=sample_rate,
num_channels=1,
)
self.bot = InMemoryAudioBuffer(
workflow_run_id=workflow_run_id,
sample_rate=sample_rate,
num_channels=1,
)
class InMemoryLogsBuffer:
"""Buffer real-time feedback events in memory during a call, then save to workflow run logs."""
def __init__(self, workflow_run_id: int):
self._workflow_run_id = workflow_run_id
self._events: List[dict] = []
self._turn_counter = 0
self._current_node_id: Optional[str] = None
self._current_node_name: Optional[str] = None
self._user_speech_start_timestamp: Optional[str] = None
self._user_speech_end_timestamp: Optional[str] = None
self._user_speech_start_from_vad = False
self._user_speech_end_from_vad = False
self._bot_speech_start_timestamp: Optional[str] = None
self._bot_speech_end_timestamp: Optional[str] = None
def set_current_node(self, node_id: str, node_name: str):
"""Set the current node ID and name to be injected into subsequent events."""
self._current_node_id = node_id
self._current_node_name = node_name
@property
def current_node_id(self) -> Optional[str]:
"""Get the current node ID."""
return self._current_node_id
@property
def current_node_name(self) -> Optional[str]:
"""Get the current node name."""
return self._current_node_name
@staticmethod
def _now_iso() -> str:
return datetime.now(UTC).isoformat(timespec="milliseconds")
def mark_user_started_speaking(
self, timestamp: Optional[str] = None, *, from_vad: bool = False
):
"""Record when the user started speaking for the current turn."""
vad_interval_is_open = (
self._user_speech_start_from_vad and self._user_speech_end_timestamp is None
)
if vad_interval_is_open and not from_vad:
return
self._user_speech_start_timestamp = timestamp or self._now_iso()
self._user_speech_end_timestamp = None
self._user_speech_start_from_vad = from_vad
self._user_speech_end_from_vad = False
self._update_latest_payload_start_timestamp(
RealtimeFeedbackType.USER_TRANSCRIPTION.value,
self._user_speech_start_timestamp,
require_final=True,
)
def mark_user_stopped_speaking(
self, timestamp: Optional[str] = None, *, from_vad: bool = False
):
"""Record when the user stopped speaking and update the latest user event."""
if self._user_speech_end_from_vad and not from_vad:
return
self._user_speech_end_timestamp = timestamp or self._now_iso()
self._user_speech_end_from_vad = from_vad
self._update_latest_payload_end_timestamp(
RealtimeFeedbackType.USER_TRANSCRIPTION.value,
self._user_speech_end_timestamp,
require_final=True,
)
def mark_bot_started_speaking(self, timestamp: Optional[str] = None):
"""Record when the bot started speaking for the current assistant turn."""
self._bot_speech_start_timestamp = timestamp or self._now_iso()
self._bot_speech_end_timestamp = None
self._update_latest_payload_start_timestamp(
RealtimeFeedbackType.BOT_TEXT.value,
self._bot_speech_start_timestamp,
)
def mark_bot_stopped_speaking(self, timestamp: Optional[str] = None):
"""Record when the bot stopped speaking and update the latest bot event."""
self._bot_speech_end_timestamp = timestamp or self._now_iso()
self._update_latest_payload_end_timestamp(
RealtimeFeedbackType.BOT_TEXT.value,
self._bot_speech_end_timestamp,
)
def _find_latest_open_payload(
self, event_type: str, *, require_final: bool = False
) -> dict | None:
for event in reversed(self._events):
if event.get("type") != event_type:
continue
payload = event.get("payload")
if not isinstance(payload, dict):
continue
if require_final and payload.get("final") is not True:
continue
if payload.get("end_timestamp"):
continue
return payload
return None
def _update_latest_payload_start_timestamp(
self, event_type: str, start_timestamp: str, *, require_final: bool = False
):
payload = self._find_latest_open_payload(
event_type, require_final=require_final
)
if payload is not None:
payload["timestamp"] = start_timestamp
def _update_latest_payload_end_timestamp(
self, event_type: str, end_timestamp: str, *, require_final: bool = False
):
payload = self._find_latest_open_payload(
event_type, require_final=require_final
)
if payload is not None:
payload["end_timestamp"] = end_timestamp
def _event_with_speech_timestamps(self, event: dict) -> dict:
event_type = event.get("type")
payload = event.get("payload")
if not isinstance(payload, dict):
return event
payload_with_timestamps = dict(payload)
if (
event_type == RealtimeFeedbackType.USER_TRANSCRIPTION.value
and payload.get("final") is True
):
if self._user_speech_start_timestamp:
payload_with_timestamps["timestamp"] = self._user_speech_start_timestamp
if self._user_speech_end_timestamp:
payload_with_timestamps["end_timestamp"] = self._user_speech_end_timestamp
elif event_type == RealtimeFeedbackType.BOT_TEXT.value:
bot_interval_is_active = self._bot_speech_end_timestamp is None
if bot_interval_is_active and self._bot_speech_start_timestamp:
payload_with_timestamps["timestamp"] = self._bot_speech_start_timestamp
if payload_with_timestamps == payload:
return event
return {**event, "payload": payload_with_timestamps}
async def append(self, event: dict):
"""Append a feedback event to the buffer with timestamp and current node."""
event = self._event_with_speech_timestamps(event)
timestamped_event = stamp_realtime_feedback_event(
event,
timestamp=self._now_iso(),
turn=self._turn_counter,
node_id=self._current_node_id,
node_name=self._current_node_name,
)
self._events.append(timestamped_event)
logger.trace(
f"Appended event {event.get('type')} to logs buffer for workflow {self._workflow_run_id}"
)
def increment_turn(self):
"""Increment turn counter (called on user transcription completion)."""
self._turn_counter += 1
logger.trace(
f"Incremented turn counter to {self._turn_counter} for workflow {self._workflow_run_id}"
)
def _sorted_events(self) -> List[dict]:
# Stable sort by the realtime (payload) timestamp when available, falling
# back to the buffer-append timestamp. Python's sort is stable, so events
# sharing a key retain their original insertion order — this keeps
# consecutive bot-text chunks of a single turn contiguous.
return sorted(self._events, key=realtime_feedback_event_sort_key)
def get_events(self) -> List[dict]:
"""Get all events for final storage, ordered by realtime timestamp."""
return self._sorted_events()
def contains_user_speech(self) -> bool:
"""Return True if any final user transcription event has non-empty text."""
for event in self._events:
if (
event.get("type") == RealtimeFeedbackType.USER_TRANSCRIPTION.value
and event.get("payload", {}).get("final") is True
and event.get("payload", {}).get("text")
):
return True
return False
def generate_transcript_text(self, *, include_end_timestamps: bool = False) -> str:
"""Generate transcript text from logged events.
Filters for rtf-user-transcription (final) and rtf-bot-text events,
formats them as '[timestamp] user/assistant: text\\n'.
"""
return _generate_transcript_text(
self._sorted_events(), include_end_timestamps=include_end_timestamps
)
@property
def is_empty(self) -> bool:
"""Check if the buffer is empty."""
return len(self._events) == 0