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"""
MAX25 sound-proxy — FreeBSD/OSS capture and playback.
Uses `sox` with OSS devices when available; falls back to raw /dev/dsp read/write.
"""
from __future__ import annotations
import os
import shutil
import subprocess
import threading
from dataclasses import dataclass
from typing import Callable, Optional
@dataclass
class OssSoundConfig:
capture: str = "/dev/dsp"
playback: str = "/dev/dsp"
sample_rate: int = 48000
channels: int = 1
class OssSoundProxy:
def __init__(self, cfg: OssSoundConfig) -> None:
self.cfg = cfg
self._rec_proc: Optional[subprocess.Popen[bytes]] = None
self._dsp_fd: Optional[int] = None
self._stop = threading.Event()
self._use_sox = shutil.which("sox") is not None
def _sox_capture_cmd(self) -> list[str]:
dev = self.cfg.capture
return [
"sox",
"-q",
"-t",
"oss",
dev,
"-r",
str(self.cfg.sample_rate),
"-c",
str(self.cfg.channels),
"-b",
"16",
"-e",
"signed-integer",
"-t",
"raw",
"-",
]
def _sox_play_cmd(self) -> list[str]:
dev = self.cfg.playback
return [
"sox",
"-q",
"-t",
"raw",
"-r",
str(self.cfg.sample_rate),
"-c",
str(self.cfg.channels),
"-b",
"16",
"-e",
"signed-integer",
"-",
"-t",
"oss",
dev,
]
def start_capture(self) -> None:
if self._use_sox:
self._rec_proc = subprocess.Popen(
self._sox_capture_cmd(),
stdout=subprocess.PIPE,
stderr=subprocess.DEVNULL,
)
return
flags = os.O_RDONLY
try:
self._dsp_fd = os.open(self.cfg.capture, flags)
except OSError as exc:
raise RuntimeError(f"OSS open {self.cfg.capture}: {exc}") from exc
def read_capture(self, nbytes: int) -> bytes:
if self._rec_proc is not None and self._rec_proc.stdout is not None:
return self._rec_proc.stdout.read(nbytes) or b""
if self._dsp_fd is not None:
try:
return os.read(self._dsp_fd, nbytes) or b""
except OSError:
return b""
return b""
def play_pcm(self, pcm: bytes) -> None:
if not pcm:
return
if self._use_sox:
subprocess.run(
self._sox_play_cmd(),
input=pcm,
check=False,
stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL,
)
return
try:
fd = os.open(self.cfg.playback, os.O_WRONLY)
except OSError:
return
try:
os.write(fd, pcm)
finally:
os.close(fd)
def sniff_loop(
self,
chunk_symbols: int,
on_pcm: Callable[[bytes], None],
stop: Optional[threading.Event] = None,
) -> None:
stop_ev = stop or self._stop
frame_bytes = max(256, (self.cfg.sample_rate // 1200) * 2 * chunk_symbols)
self.start_capture()
try:
while not stop_ev.is_set():
chunk = self.read_capture(frame_bytes)
if not chunk:
break
on_pcm(chunk)
finally:
self.close()
def close(self) -> None:
self._stop.set()
if self._rec_proc is not None and self._rec_proc.poll() is None:
self._rec_proc.terminate()
try:
self._rec_proc.wait(timeout=1.0)
except subprocess.TimeoutExpired:
self._rec_proc.kill()
self._rec_proc = None
if self._dsp_fd is not None:
try:
os.close(self._dsp_fd)
except OSError:
pass
self._dsp_fd = None
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