Keysat
62 lines
2.6 KiB
Python
62 lines
2.6 KiB
Python
"""Audio acquisition (§4.1). Spark Control transcribes audio you fetch — this fetches it.
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- Podcast enclosures: a plain streaming download that follows the Podtrac/Megaphone redirects to the
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final signed CDN object (download immediately; resolved URLs carry short-lived params).
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- YouTube: yt-dlp (audio-only → 16 kHz mono WAV). NOTE: 2026 YouTube enforces PO Tokens broadly — run
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the `bgutil-ytdlp-pot-provider` sidecar or pulls will 403. yt-dlp is treated as a LAST resort; prefer
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the RSS enclosure where a show publishes both (ToS: downloading YT audio violates YouTube ToS).
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"""
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from __future__ import annotations
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import subprocess
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from pathlib import Path
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import requests
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DEFAULT_UA = "Ten31SignalEngine/0.1 (+https://ten31.xyz)"
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def download_enclosure(url: str, dest: str | Path, *, user_agent: str = DEFAULT_UA, timeout: int = 120) -> Path:
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dest = Path(dest)
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dest.parent.mkdir(parents=True, exist_ok=True)
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with requests.get(url, stream=True, allow_redirects=True,
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headers={"User-Agent": user_agent}, timeout=timeout) as r:
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r.raise_for_status()
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with open(dest, "wb") as f:
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for chunk in r.iter_content(chunk_size=1 << 16):
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f.write(chunk)
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return dest
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def to_wav_16k_mono(src: str | Path, dst: str | Path) -> Path:
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"""Normalize any audio to 16 kHz mono PCM WAV (what the ASR endpoint wants). Requires ffmpeg."""
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dst = Path(dst)
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dst.parent.mkdir(parents=True, exist_ok=True)
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subprocess.run(
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["ffmpeg", "-y", "-i", str(src), "-ar", "16000", "-ac", "1", "-f", "wav", str(dst)],
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check=True, capture_output=True,
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)
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return dst
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def download_youtube_audio(url: str, out_dir: str | Path, *, archive_file: str | Path | None = None) -> Path:
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"""Audio-only via yt-dlp → 16 kHz mono WAV. `archive_file` (yt-dlp --download-archive) is the
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canonical 'only-new' dedup for channel/playlist back-catalog pulls."""
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out_dir = Path(out_dir)
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out_dir.mkdir(parents=True, exist_ok=True)
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cmd = [
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"yt-dlp", "-f", "bestaudio/best", "-x", "--audio-format", "wav",
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"--postprocessor-args", "ffmpeg:-ar 16000 -ac 1",
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"-o", str(out_dir / "%(id)s.%(ext)s"),
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"--no-progress",
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]
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if archive_file:
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cmd += ["--download-archive", str(archive_file)]
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cmd.append(url)
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subprocess.run(cmd, check=True, capture_output=True)
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# yt-dlp names the file by video id; return the newest wav
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wavs = sorted(out_dir.glob("*.wav"), key=lambda p: p.stat().st_mtime)
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if not wavs:
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raise RuntimeError("yt-dlp produced no wav (PO-token/cookies issue? see module docstring)")
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return wavs[-1]
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