mirror of
https://github.com/smittix/intercept.git
synced 2026-04-24 22:59:59 -07:00
1ee64efc81
Fix infinite CPU spin in PD120 decoding caused by a 1-sample rounding mismatch between line_samples (24407) and the sum of sub-component samples (24408). The feed() while loop would re-enter _decode_line() endlessly when the buffer was too short by 1 sample. Added a stall guard that breaks the loop when no progress is made. Fix false "leader tone detected" in the signal monitor by requiring the detected tone to dominate the other tone by 2x, matching the approach already used by the VIS detector. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
906 lines
34 KiB
Python
906 lines
34 KiB
Python
"""SSTV decoder orchestrator.
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Provides the SSTVDecoder class that manages the full pipeline:
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rtl_fm subprocess -> audio stream -> VIS detection -> image decoding -> PNG output.
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Also contains DopplerTracker and supporting dataclasses migrated from the
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original monolithic utils/sstv.py.
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"""
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from __future__ import annotations
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import base64
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import contextlib
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import io
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import subprocess
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import threading
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import time
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from dataclasses import dataclass
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from datetime import datetime, timedelta, timezone
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from pathlib import Path
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from typing import Callable
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import numpy as np
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from utils.logging import get_logger
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from .constants import ISS_SSTV_FREQ, SAMPLE_RATE, SPEED_OF_LIGHT
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from .dsp import goertzel_mag, normalize_audio
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from .image_decoder import SSTVImageDecoder
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from .modes import get_mode
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from .vis import VISDetector
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logger = get_logger('intercept.sstv')
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try:
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from PIL import Image as PILImage
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except ImportError:
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PILImage = None # type: ignore[assignment,misc]
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# ---------------------------------------------------------------------------
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# Dataclasses
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# ---------------------------------------------------------------------------
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@dataclass
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class DopplerInfo:
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"""Doppler shift information."""
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frequency_hz: float
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shift_hz: float
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range_rate_km_s: float
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elevation: float
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azimuth: float
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timestamp: datetime
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def to_dict(self) -> dict:
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return {
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'frequency_hz': self.frequency_hz,
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'shift_hz': round(self.shift_hz, 1),
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'range_rate_km_s': round(self.range_rate_km_s, 3),
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'elevation': round(self.elevation, 1),
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'azimuth': round(self.azimuth, 1),
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'timestamp': self.timestamp.isoformat(),
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}
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@dataclass
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class SSTVImage:
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"""Decoded SSTV image."""
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filename: str
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path: Path
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mode: str
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timestamp: datetime
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frequency: float
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size_bytes: int = 0
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url_prefix: str = '/sstv'
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def to_dict(self) -> dict:
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return {
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'filename': self.filename,
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'path': str(self.path),
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'mode': self.mode,
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'timestamp': self.timestamp.isoformat(),
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'frequency': self.frequency,
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'size_bytes': self.size_bytes,
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'url': f'{self.url_prefix}/images/{self.filename}'
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}
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@dataclass
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class DecodeProgress:
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"""SSTV decode progress update."""
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status: str # 'detecting', 'decoding', 'complete', 'error'
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mode: str | None = None
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progress_percent: int = 0
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message: str | None = None
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image: SSTVImage | None = None
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signal_level: int | None = None # 0-100 RMS audio level, None = not measured
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sstv_tone: str | None = None # 'leader', 'sync', 'noise', None
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vis_state: str | None = None # VIS detector state name
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partial_image: str | None = None # base64 data URL of partial decode
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def to_dict(self) -> dict:
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result: dict = {
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'type': 'sstv_progress',
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'status': self.status,
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'progress': self.progress_percent,
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}
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if self.mode:
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result['mode'] = self.mode
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if self.message:
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result['message'] = self.message
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if self.image:
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result['image'] = self.image.to_dict()
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if self.signal_level is not None:
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result['signal_level'] = self.signal_level
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if self.sstv_tone:
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result['sstv_tone'] = self.sstv_tone
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if self.vis_state:
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result['vis_state'] = self.vis_state
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if self.partial_image:
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result['partial_image'] = self.partial_image
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return result
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# ---------------------------------------------------------------------------
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# DopplerTracker
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# ---------------------------------------------------------------------------
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class DopplerTracker:
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"""Real-time Doppler shift calculator for satellite tracking.
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Uses skyfield to calculate the range rate between observer and satellite,
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then computes the Doppler-shifted receive frequency.
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"""
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def __init__(self, satellite_name: str = 'ISS'):
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self._satellite_name = satellite_name
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self._observer_lat: float | None = None
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self._observer_lon: float | None = None
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self._satellite = None
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self._observer = None
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self._ts = None
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self._enabled = False
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def configure(self, latitude: float, longitude: float) -> bool:
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"""Configure the Doppler tracker with observer location."""
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try:
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from skyfield.api import EarthSatellite, load, wgs84
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from data.satellites import TLE_SATELLITES
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tle_data = TLE_SATELLITES.get(self._satellite_name)
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if not tle_data:
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logger.error(f"No TLE data for satellite: {self._satellite_name}")
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return False
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self._ts = load.timescale()
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self._satellite = EarthSatellite(tle_data[1], tle_data[2], tle_data[0], self._ts)
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self._observer = wgs84.latlon(latitude, longitude)
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self._observer_lat = latitude
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self._observer_lon = longitude
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self._enabled = True
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logger.info(f"Doppler tracker configured for {self._satellite_name} at ({latitude}, {longitude})")
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return True
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except ImportError:
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logger.warning("skyfield not available - Doppler tracking disabled")
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return False
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except Exception as e:
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logger.error(f"Failed to configure Doppler tracker: {e}")
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return False
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@property
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def is_enabled(self) -> bool:
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return self._enabled
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def calculate(self, nominal_freq_mhz: float) -> DopplerInfo | None:
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"""Calculate current Doppler-shifted frequency."""
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if not self._enabled or not self._satellite or not self._observer:
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return None
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try:
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t = self._ts.now()
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difference = self._satellite - self._observer
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topocentric = difference.at(t)
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alt, az, distance = topocentric.altaz()
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dt_seconds = 1.0
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t_future = self._ts.utc(t.utc_datetime() + timedelta(seconds=dt_seconds))
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topocentric_future = difference.at(t_future)
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_, _, distance_future = topocentric_future.altaz()
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range_rate_km_s = (distance_future.km - distance.km) / dt_seconds
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nominal_freq_hz = nominal_freq_mhz * 1_000_000
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doppler_factor = 1 - (range_rate_km_s * 1000 / SPEED_OF_LIGHT)
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corrected_freq_hz = nominal_freq_hz * doppler_factor
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shift_hz = corrected_freq_hz - nominal_freq_hz
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return DopplerInfo(
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frequency_hz=corrected_freq_hz,
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shift_hz=shift_hz,
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range_rate_km_s=range_rate_km_s,
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elevation=alt.degrees,
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azimuth=az.degrees,
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timestamp=datetime.now(timezone.utc)
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)
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except Exception as e:
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logger.error(f"Doppler calculation failed: {e}")
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return None
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# ---------------------------------------------------------------------------
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# SSTVDecoder
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# ---------------------------------------------------------------------------
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class SSTVDecoder:
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"""SSTV decoder using pure-Python DSP with Doppler compensation."""
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RETUNE_THRESHOLD_HZ = 500
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DOPPLER_UPDATE_INTERVAL = 5
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def __init__(self, output_dir: str | Path | None = None, url_prefix: str = '/sstv'):
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self._rtl_process = None
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self._running = False
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self._lock = threading.Lock()
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self._callback: Callable[[DecodeProgress], None] | None = None
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self._output_dir = Path(output_dir) if output_dir else Path('instance/sstv_images')
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self._url_prefix = url_prefix
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self._images: list[SSTVImage] = []
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self._decode_thread = None
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self._doppler_thread = None
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self._frequency = ISS_SSTV_FREQ
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self._modulation = 'fm'
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self._current_tuned_freq_hz: int = 0
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self._device_index = 0
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# Doppler tracking
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self._doppler_tracker = DopplerTracker('ISS')
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self._doppler_enabled = False
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self._last_doppler_info: DopplerInfo | None = None
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# Ensure output directory exists
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self._output_dir.mkdir(parents=True, exist_ok=True)
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@property
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def is_running(self) -> bool:
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return self._running
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@property
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def decoder_available(self) -> str:
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"""Return name of available decoder. Always available with pure Python."""
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return 'python-sstv'
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def set_callback(self, callback: Callable[[DecodeProgress], None]) -> None:
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"""Set callback for decode progress updates."""
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self._callback = callback
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def start(
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self,
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frequency: float = ISS_SSTV_FREQ,
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device_index: int = 0,
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latitude: float | None = None,
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longitude: float | None = None,
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modulation: str = 'fm',
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) -> bool:
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"""Start SSTV decoder listening on specified frequency.
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Args:
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frequency: Frequency in MHz (default: 145.800 for ISS).
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device_index: RTL-SDR device index.
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latitude: Observer latitude for Doppler correction.
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longitude: Observer longitude for Doppler correction.
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modulation: Demodulation mode for rtl_fm (fm, usb, lsb).
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Returns:
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True if started successfully.
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"""
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with self._lock:
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if self._running:
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return True
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self._frequency = frequency
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self._device_index = device_index
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self._modulation = modulation
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# Configure Doppler tracking if location provided
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self._doppler_enabled = False
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if latitude is not None and longitude is not None:
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if self._doppler_tracker.configure(latitude, longitude):
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self._doppler_enabled = True
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logger.info(f"Doppler tracking enabled for location ({latitude}, {longitude})")
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else:
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logger.warning("Doppler tracking unavailable - using fixed frequency")
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try:
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freq_hz = self._get_doppler_corrected_freq_hz()
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self._current_tuned_freq_hz = freq_hz
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# Set _running BEFORE starting the pipeline so the decode
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# thread sees it as True on its first loop iteration.
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self._running = True
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self._start_pipeline(freq_hz)
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# Start Doppler tracking thread if enabled
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if self._doppler_enabled:
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self._doppler_thread = threading.Thread(
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target=self._doppler_tracking_loop, daemon=True)
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self._doppler_thread.start()
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logger.info(f"SSTV decoder started on {frequency} MHz with Doppler tracking")
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self._emit_progress(DecodeProgress(
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status='detecting',
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message=f'Listening on {frequency} MHz with Doppler tracking...'
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))
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else:
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logger.info(f"SSTV decoder started on {frequency} MHz (no Doppler tracking)")
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self._emit_progress(DecodeProgress(
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status='detecting',
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message=f'Listening on {frequency} MHz...'
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))
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return True
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except Exception as e:
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self._running = False
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logger.error(f"Failed to start SSTV decoder: {e}")
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self._emit_progress(DecodeProgress(
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status='error',
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message=str(e)
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))
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return False
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def _get_doppler_corrected_freq_hz(self) -> int:
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"""Get the Doppler-corrected frequency in Hz."""
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nominal_freq_hz = int(self._frequency * 1_000_000)
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if self._doppler_enabled:
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doppler_info = self._doppler_tracker.calculate(self._frequency)
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if doppler_info:
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self._last_doppler_info = doppler_info
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corrected_hz = int(doppler_info.frequency_hz)
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logger.info(
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f"Doppler correction: {doppler_info.shift_hz:+.1f} Hz "
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f"(range rate: {doppler_info.range_rate_km_s:+.3f} km/s, "
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f"el: {doppler_info.elevation:.1f}\u00b0)"
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)
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return corrected_hz
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return nominal_freq_hz
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def _start_pipeline(self, freq_hz: int) -> None:
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"""Start the rtl_fm -> Python decode pipeline."""
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rtl_cmd = [
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'rtl_fm',
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'-d', str(self._device_index),
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'-f', str(freq_hz),
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'-M', self._modulation,
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'-s', str(SAMPLE_RATE),
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'-r', str(SAMPLE_RATE),
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'-l', '0', # No squelch
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'-'
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]
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logger.info(f"Starting rtl_fm: {' '.join(rtl_cmd)}")
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self._rtl_process = subprocess.Popen(
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rtl_cmd,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE
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)
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# Start decode thread that reads from rtl_fm stdout
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self._decode_thread = threading.Thread(
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target=self._decode_audio_stream, daemon=True)
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self._decode_thread.start()
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def _decode_audio_stream(self) -> None:
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"""Read audio from rtl_fm and decode SSTV images.
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Runs in a background thread. Reads 100ms chunks of int16 PCM,
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feeds through VIS detector, then image decoder.
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"""
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chunk_bytes = SAMPLE_RATE // 10 * 2 # 100ms of int16 = 9600 bytes
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vis_detector = VISDetector(sample_rate=SAMPLE_RATE)
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image_decoder: SSTVImageDecoder | None = None
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current_mode_name: str | None = None
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chunk_counter = 0
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last_partial_pct = -1
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logger.info("Audio decode thread started")
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rtl_fm_error: str = ''
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while self._running and self._rtl_process:
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try:
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raw_data = self._rtl_process.stdout.read(chunk_bytes)
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if not raw_data:
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if self._running:
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# Read stderr to diagnose why rtl_fm exited
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stderr_msg = ''
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if self._rtl_process and self._rtl_process.stderr:
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with contextlib.suppress(Exception):
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stderr_msg = self._rtl_process.stderr.read().decode(
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errors='replace').strip()
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rc = self._rtl_process.poll() if self._rtl_process else None
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logger.warning(
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f"rtl_fm stream ended unexpectedly "
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f"(exit code: {rc})"
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)
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if stderr_msg:
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logger.warning(f"rtl_fm stderr: {stderr_msg}")
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rtl_fm_error = stderr_msg
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break
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# Convert int16 PCM to float64
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n_samples = len(raw_data) // 2
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if n_samples == 0:
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continue
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raw_samples = np.frombuffer(raw_data[:n_samples * 2], dtype=np.int16)
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samples = normalize_audio(raw_samples)
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chunk_counter += 1
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if image_decoder is not None:
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# Currently decoding an image
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complete = image_decoder.feed(samples)
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# Encode partial image every 5% progress
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pct = image_decoder.progress_percent
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partial_url = None
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if pct >= last_partial_pct + 5 or complete:
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last_partial_pct = pct
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try:
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img = image_decoder.get_image()
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if img is not None:
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buf = io.BytesIO()
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img.save(buf, format='JPEG', quality=40)
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b64 = base64.b64encode(buf.getvalue()).decode('ascii')
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partial_url = f'data:image/jpeg;base64,{b64}'
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except Exception:
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pass
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# Emit progress
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self._emit_progress(DecodeProgress(
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status='decoding',
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mode=current_mode_name,
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progress_percent=pct,
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message=f'Decoding {current_mode_name}: {pct}%',
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partial_image=partial_url,
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))
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if complete:
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# Save image
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self._save_decoded_image(image_decoder, current_mode_name)
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image_decoder = None
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current_mode_name = None
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vis_detector.reset()
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else:
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# Scanning for VIS header
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result = vis_detector.feed(samples)
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if result is not None:
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vis_code, mode_name = result
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logger.info(f"VIS detected: code={vis_code}, mode={mode_name}")
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mode_spec = get_mode(vis_code)
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if mode_spec:
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current_mode_name = mode_name
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image_decoder = SSTVImageDecoder(
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mode_spec,
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sample_rate=SAMPLE_RATE,
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)
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self._emit_progress(DecodeProgress(
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status='decoding',
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mode=mode_name,
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progress_percent=0,
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message=f'Detected {mode_name} - decoding...'
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))
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else:
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logger.warning(f"No mode spec for VIS code {vis_code}")
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vis_detector.reset()
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# Emit signal level metrics every ~500ms (every 5th 100ms chunk)
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if chunk_counter % 5 == 0 and image_decoder is None:
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rms = float(np.sqrt(np.mean(samples ** 2)))
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signal_level = min(100, int(rms * 500))
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leader_energy = goertzel_mag(samples, 1900.0, SAMPLE_RATE)
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sync_energy = goertzel_mag(samples, 1200.0, SAMPLE_RATE)
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noise_floor = max(rms * 0.5, 0.001)
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# Require the tone to both exceed the noise floor AND
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# dominate the other tone by 2x to avoid false positives
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# from broadband noise.
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if (leader_energy > noise_floor * 5
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and leader_energy > sync_energy * 2):
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sstv_tone = 'leader'
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elif (sync_energy > noise_floor * 5
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and sync_energy > leader_energy * 2):
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sstv_tone = 'sync'
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elif signal_level > 10:
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sstv_tone = 'noise'
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else:
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sstv_tone = None
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self._emit_progress(DecodeProgress(
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status='detecting',
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message='Listening...',
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signal_level=signal_level,
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sstv_tone=sstv_tone,
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vis_state=vis_detector.state.value,
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))
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except Exception as e:
|
|
logger.error(f"Error in decode thread: {e}")
|
|
if not self._running:
|
|
break
|
|
time.sleep(0.1)
|
|
|
|
# Clean up if the thread exits while we thought we were running.
|
|
# This prevents a "ghost running" state where is_running is True
|
|
# but the thread has already died (e.g. rtl_fm exited).
|
|
with self._lock:
|
|
was_running = self._running
|
|
self._running = False
|
|
if was_running and self._rtl_process:
|
|
with contextlib.suppress(Exception):
|
|
self._rtl_process.terminate()
|
|
self._rtl_process.wait(timeout=2)
|
|
self._rtl_process = None
|
|
|
|
if was_running:
|
|
logger.warning("Audio decode thread stopped unexpectedly")
|
|
err_detail = rtl_fm_error.split('\n')[-1] if rtl_fm_error else ''
|
|
msg = f'rtl_fm failed: {err_detail}' if err_detail else 'Decode pipeline stopped unexpectedly'
|
|
self._emit_progress(DecodeProgress(
|
|
status='error',
|
|
message=msg
|
|
))
|
|
else:
|
|
logger.info("Audio decode thread stopped")
|
|
|
|
def _save_decoded_image(self, decoder: SSTVImageDecoder,
|
|
mode_name: str | None) -> None:
|
|
"""Save a completed decoded image to disk."""
|
|
try:
|
|
img = decoder.get_image()
|
|
if img is None:
|
|
logger.error("Failed to get image from decoder (Pillow not available?)")
|
|
self._emit_progress(DecodeProgress(
|
|
status='error',
|
|
message='Failed to create image - Pillow not installed'
|
|
))
|
|
return
|
|
|
|
timestamp = datetime.now(timezone.utc)
|
|
filename = f"sstv_{timestamp.strftime('%Y%m%d_%H%M%S')}_{mode_name or 'unknown'}.png"
|
|
filepath = self._output_dir / filename
|
|
img.save(filepath, 'PNG')
|
|
|
|
sstv_image = SSTVImage(
|
|
filename=filename,
|
|
path=filepath,
|
|
mode=mode_name or 'Unknown',
|
|
timestamp=timestamp,
|
|
frequency=self._frequency,
|
|
size_bytes=filepath.stat().st_size,
|
|
url_prefix=self._url_prefix,
|
|
)
|
|
self._images.append(sstv_image)
|
|
|
|
logger.info(f"SSTV image saved: {filename} ({sstv_image.size_bytes} bytes)")
|
|
self._emit_progress(DecodeProgress(
|
|
status='complete',
|
|
mode=mode_name,
|
|
progress_percent=100,
|
|
message='Image decoded',
|
|
image=sstv_image,
|
|
))
|
|
|
|
except Exception as e:
|
|
logger.error(f"Error saving decoded image: {e}")
|
|
self._emit_progress(DecodeProgress(
|
|
status='error',
|
|
message=f'Error saving image: {e}'
|
|
))
|
|
|
|
def _doppler_tracking_loop(self) -> None:
|
|
"""Background thread that monitors Doppler shift and retunes when needed."""
|
|
logger.info("Doppler tracking thread started")
|
|
|
|
while self._running and self._doppler_enabled:
|
|
time.sleep(self.DOPPLER_UPDATE_INTERVAL)
|
|
|
|
if not self._running:
|
|
break
|
|
|
|
try:
|
|
doppler_info = self._doppler_tracker.calculate(self._frequency)
|
|
if not doppler_info:
|
|
continue
|
|
|
|
self._last_doppler_info = doppler_info
|
|
new_freq_hz = int(doppler_info.frequency_hz)
|
|
freq_diff = abs(new_freq_hz - self._current_tuned_freq_hz)
|
|
|
|
logger.debug(
|
|
f"Doppler: {doppler_info.shift_hz:+.1f} Hz, "
|
|
f"el: {doppler_info.elevation:.1f}\u00b0, "
|
|
f"diff from tuned: {freq_diff} Hz"
|
|
)
|
|
|
|
self._emit_progress(DecodeProgress(
|
|
status='detecting',
|
|
message=f'Doppler: {doppler_info.shift_hz:+.0f} Hz, elevation: {doppler_info.elevation:.1f}\u00b0'
|
|
))
|
|
|
|
if freq_diff >= self.RETUNE_THRESHOLD_HZ:
|
|
logger.info(
|
|
f"Retuning: {self._current_tuned_freq_hz} -> {new_freq_hz} Hz "
|
|
f"(Doppler shift: {doppler_info.shift_hz:+.1f} Hz)"
|
|
)
|
|
self._retune_rtl_fm(new_freq_hz)
|
|
|
|
except Exception as e:
|
|
logger.error(f"Doppler tracking error: {e}")
|
|
|
|
logger.info("Doppler tracking thread stopped")
|
|
|
|
def _retune_rtl_fm(self, new_freq_hz: int) -> None:
|
|
"""Retune rtl_fm to a new frequency by restarting the process."""
|
|
with self._lock:
|
|
if not self._running:
|
|
return
|
|
|
|
if self._rtl_process:
|
|
try:
|
|
self._rtl_process.terminate()
|
|
self._rtl_process.wait(timeout=2)
|
|
except Exception:
|
|
with contextlib.suppress(Exception):
|
|
self._rtl_process.kill()
|
|
|
|
rtl_cmd = [
|
|
'rtl_fm',
|
|
'-d', str(self._device_index),
|
|
'-f', str(new_freq_hz),
|
|
'-M', self._modulation,
|
|
'-s', str(SAMPLE_RATE),
|
|
'-r', str(SAMPLE_RATE),
|
|
'-l', '0',
|
|
'-'
|
|
]
|
|
|
|
logger.debug(f"Restarting rtl_fm: {' '.join(rtl_cmd)}")
|
|
|
|
self._rtl_process = subprocess.Popen(
|
|
rtl_cmd,
|
|
stdout=subprocess.PIPE,
|
|
stderr=subprocess.PIPE
|
|
)
|
|
|
|
self._current_tuned_freq_hz = new_freq_hz
|
|
|
|
@property
|
|
def last_doppler_info(self) -> DopplerInfo | None:
|
|
"""Get the most recent Doppler calculation."""
|
|
return self._last_doppler_info
|
|
|
|
@property
|
|
def doppler_enabled(self) -> bool:
|
|
"""Check if Doppler tracking is enabled."""
|
|
return self._doppler_enabled
|
|
|
|
def stop(self) -> None:
|
|
"""Stop SSTV decoder."""
|
|
with self._lock:
|
|
self._running = False
|
|
|
|
if self._rtl_process:
|
|
try:
|
|
self._rtl_process.terminate()
|
|
self._rtl_process.wait(timeout=5)
|
|
except Exception:
|
|
with contextlib.suppress(Exception):
|
|
self._rtl_process.kill()
|
|
self._rtl_process = None
|
|
|
|
logger.info("SSTV decoder stopped")
|
|
|
|
def get_images(self) -> list[SSTVImage]:
|
|
"""Get list of decoded images."""
|
|
self._scan_images()
|
|
return list(self._images)
|
|
|
|
def delete_image(self, filename: str) -> bool:
|
|
"""Delete a single decoded image by filename."""
|
|
filepath = self._output_dir / filename
|
|
if not filepath.exists():
|
|
return False
|
|
filepath.unlink()
|
|
self._images = [img for img in self._images if img.filename != filename]
|
|
logger.info(f"Deleted SSTV image: {filename}")
|
|
return True
|
|
|
|
def delete_all_images(self) -> int:
|
|
"""Delete all decoded images. Returns count deleted."""
|
|
count = 0
|
|
for filepath in self._output_dir.glob('*.png'):
|
|
filepath.unlink()
|
|
count += 1
|
|
self._images.clear()
|
|
logger.info(f"Deleted all SSTV images ({count} files)")
|
|
return count
|
|
|
|
def _scan_images(self) -> None:
|
|
"""Scan output directory for images."""
|
|
known_filenames = {img.filename for img in self._images}
|
|
|
|
for filepath in self._output_dir.glob('*.png'):
|
|
if filepath.name not in known_filenames:
|
|
try:
|
|
stat = filepath.stat()
|
|
image = SSTVImage(
|
|
filename=filepath.name,
|
|
path=filepath,
|
|
mode='Unknown',
|
|
timestamp=datetime.fromtimestamp(stat.st_mtime, tz=timezone.utc),
|
|
frequency=self._frequency,
|
|
size_bytes=stat.st_size,
|
|
url_prefix=self._url_prefix,
|
|
)
|
|
self._images.append(image)
|
|
except Exception as e:
|
|
logger.warning(f"Error scanning image {filepath}: {e}")
|
|
|
|
def _emit_progress(self, progress: DecodeProgress) -> None:
|
|
"""Emit progress update to callback."""
|
|
if self._callback:
|
|
try:
|
|
self._callback(progress)
|
|
except Exception as e:
|
|
logger.error(f"Error in progress callback: {e}")
|
|
|
|
def decode_file(self, audio_path: str | Path) -> list[SSTVImage]:
|
|
"""Decode SSTV image(s) from an audio file.
|
|
|
|
Reads a WAV file and processes it through VIS detection + image
|
|
decoding using the pure Python pipeline.
|
|
|
|
Args:
|
|
audio_path: Path to WAV audio file.
|
|
|
|
Returns:
|
|
List of decoded images.
|
|
"""
|
|
import wave
|
|
|
|
audio_path = Path(audio_path)
|
|
if not audio_path.exists():
|
|
raise FileNotFoundError(f"Audio file not found: {audio_path}")
|
|
|
|
images: list[SSTVImage] = []
|
|
|
|
try:
|
|
with wave.open(str(audio_path), 'rb') as wf:
|
|
n_channels = wf.getnchannels()
|
|
sample_width = wf.getsampwidth()
|
|
file_sample_rate = wf.getframerate()
|
|
n_frames = wf.getnframes()
|
|
|
|
logger.info(
|
|
f"Decoding WAV: {n_channels}ch, {sample_width*8}bit, "
|
|
f"{file_sample_rate}Hz, {n_frames} frames"
|
|
)
|
|
|
|
# Read all audio data
|
|
raw_data = wf.readframes(n_frames)
|
|
|
|
# Convert to float64 mono
|
|
if sample_width == 2:
|
|
audio = np.frombuffer(raw_data, dtype=np.int16).astype(np.float64) / 32768.0
|
|
elif sample_width == 1:
|
|
audio = np.frombuffer(raw_data, dtype=np.uint8).astype(np.float64) / 128.0 - 1.0
|
|
elif sample_width == 4:
|
|
audio = np.frombuffer(raw_data, dtype=np.int32).astype(np.float64) / 2147483648.0
|
|
else:
|
|
raise ValueError(f"Unsupported sample width: {sample_width}")
|
|
|
|
# If stereo, take left channel
|
|
if n_channels > 1:
|
|
audio = audio[::n_channels]
|
|
|
|
# Resample if needed
|
|
if file_sample_rate != SAMPLE_RATE:
|
|
audio = self._resample(audio, file_sample_rate, SAMPLE_RATE)
|
|
|
|
# Process through VIS detector + image decoder
|
|
vis_detector = VISDetector(sample_rate=SAMPLE_RATE)
|
|
image_decoder: SSTVImageDecoder | None = None
|
|
current_mode_name: str | None = None
|
|
|
|
chunk_size = SAMPLE_RATE // 10 # 100ms chunks
|
|
offset = 0
|
|
|
|
while offset < len(audio):
|
|
chunk = audio[offset:offset + chunk_size]
|
|
offset += chunk_size
|
|
|
|
if image_decoder is not None:
|
|
complete = image_decoder.feed(chunk)
|
|
if complete:
|
|
img = image_decoder.get_image()
|
|
if img is not None:
|
|
timestamp = datetime.now(timezone.utc)
|
|
filename = f"sstv_{timestamp.strftime('%Y%m%d_%H%M%S')}_{current_mode_name or 'unknown'}.png"
|
|
filepath = self._output_dir / filename
|
|
img.save(filepath, 'PNG')
|
|
|
|
sstv_image = SSTVImage(
|
|
filename=filename,
|
|
path=filepath,
|
|
mode=current_mode_name or 'Unknown',
|
|
timestamp=timestamp,
|
|
frequency=0,
|
|
size_bytes=filepath.stat().st_size,
|
|
url_prefix=self._url_prefix,
|
|
)
|
|
images.append(sstv_image)
|
|
self._images.append(sstv_image)
|
|
logger.info(f"Decoded image from file: {filename}")
|
|
|
|
image_decoder = None
|
|
current_mode_name = None
|
|
vis_detector.reset()
|
|
else:
|
|
result = vis_detector.feed(chunk)
|
|
if result is not None:
|
|
vis_code, mode_name = result
|
|
logger.info(f"VIS detected in file: code={vis_code}, mode={mode_name}")
|
|
|
|
mode_spec = get_mode(vis_code)
|
|
if mode_spec:
|
|
current_mode_name = mode_name
|
|
image_decoder = SSTVImageDecoder(
|
|
mode_spec,
|
|
sample_rate=SAMPLE_RATE,
|
|
)
|
|
else:
|
|
vis_detector.reset()
|
|
|
|
except wave.Error as e:
|
|
logger.error(f"Error reading WAV file: {e}")
|
|
raise
|
|
except Exception as e:
|
|
logger.error(f"Error decoding audio file: {e}")
|
|
raise
|
|
|
|
return images
|
|
|
|
@staticmethod
|
|
def _resample(audio: np.ndarray, from_rate: int, to_rate: int) -> np.ndarray:
|
|
"""Simple resampling using linear interpolation."""
|
|
if from_rate == to_rate:
|
|
return audio
|
|
|
|
ratio = to_rate / from_rate
|
|
new_length = int(len(audio) * ratio)
|
|
indices = np.linspace(0, len(audio) - 1, new_length)
|
|
return np.interp(indices, np.arange(len(audio)), audio)
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Module-level singletons
|
|
# ---------------------------------------------------------------------------
|
|
|
|
_decoder: SSTVDecoder | None = None
|
|
|
|
|
|
def get_sstv_decoder() -> SSTVDecoder:
|
|
"""Get or create the global SSTV decoder instance."""
|
|
global _decoder
|
|
if _decoder is None:
|
|
_decoder = SSTVDecoder()
|
|
return _decoder
|
|
|
|
|
|
def is_sstv_available() -> bool:
|
|
"""Check if SSTV decoding is available.
|
|
|
|
Always True with the pure-Python decoder (requires only numpy/Pillow).
|
|
"""
|
|
return True
|
|
|
|
|
|
_general_decoder: SSTVDecoder | None = None
|
|
|
|
|
|
def get_general_sstv_decoder() -> SSTVDecoder:
|
|
"""Get or create the global general SSTV decoder instance."""
|
|
global _general_decoder
|
|
if _general_decoder is None:
|
|
_general_decoder = SSTVDecoder(
|
|
output_dir='instance/sstv_general_images',
|
|
url_prefix='/sstv-general',
|
|
)
|
|
return _general_decoder
|