dograh/api/utils/hold_audio.py
2026-02-05 21:02:02 +05:30

80 lines
2.1 KiB
Python

"""Utility for loading and playing hold audio files."""
from typing import Dict
import soundfile as sf
from loguru import logger
from api.constants import APP_ROOT_DIR
# Cache for loaded audio data
_audio_cache: Dict[str, bytes] = {}
def load_hold_audio(sample_rate: int) -> bytes:
"""Load hold audio file as raw PCM bytes for the given sample rate.
Args:
sample_rate: The sample rate to load (8000 or 16000)
Returns:
Raw PCM audio bytes (16-bit signed, mono)
Raises:
FileNotFoundError: If the audio file doesn't exist
ValueError: If sample rate is not supported
"""
if sample_rate not in (8000, 16000):
raise ValueError(
f"Unsupported sample rate: {sample_rate}. Must be 8000 or 16000"
)
cache_key = f"hold_ring_{sample_rate}"
if cache_key in _audio_cache:
return _audio_cache[cache_key]
# Construct path to the audio file
assets_dir = APP_ROOT_DIR / "assets"
audio_file = assets_dir / f"transfer_hold_ring_{sample_rate}.wav"
if not audio_file.exists():
raise FileNotFoundError(f"Hold audio file not found: {audio_file}")
# Load the audio file
audio_data, file_sample_rate = sf.read(str(audio_file), dtype="int16")
if file_sample_rate != sample_rate:
logger.warning(
f"Audio file sample rate ({file_sample_rate}) doesn't match "
f"requested rate ({sample_rate})"
)
# Convert to bytes
audio_bytes = audio_data.tobytes()
# Cache for future use
_audio_cache[cache_key] = audio_bytes
logger.debug(
f"Loaded hold audio: {audio_file.name}, "
f"duration={len(audio_data) / sample_rate:.2f}s"
)
return audio_bytes
def get_hold_audio_duration_ms(sample_rate: int) -> int:
"""Get the duration of the hold audio in milliseconds.
Args:
sample_rate: The sample rate (8000 or 16000)
Returns:
Duration in milliseconds
"""
audio_bytes = load_hold_audio(sample_rate)
# 2 bytes per sample (16-bit PCM)
num_samples = len(audio_bytes) // 2
duration_ms = int((num_samples / sample_rate) * 1000)
return duration_ms