Handle pw-record versions without raw support

audio.py

@@ -197,7 +197,7 @@ def recording_command(target=""):
         return cmd
     if shutil.which("pw-record"):
         cmd = [
-            "pw-record", "--raw", f"--rate={RATE}",
+            "pw-record", *_pw_record_raw_option(), f"--rate={RATE}",
             f"--channels={CHANNELS}", "--format=s16",
         ]
         if target:
@@ -207,6 +207,25 @@ def recording_command(target=""):
     return []
 
 
+def _pw_record_raw_option():
+    """Use --raw only on pw-record releases that provide it.
+
+    PipeWire 1.0, including Ubuntu 24.04's build, writes raw PCM to stdout but
+    rejects the newer --raw option. A rejected option ends the recorder before
+    it receives sound, so ask the installed binary which form it understands.
+    """
+    try:
+        result = subprocess.run(
+            ["pw-record", "--help"], capture_output=True, text=True, timeout=2
+        )
+        help_text = (result.stdout or "") + (result.stderr or "")
+    except (subprocess.SubprocessError, OSError):
+        return ["--raw"]  # preserve the existing command when probing itself fails
+    if not help_text.strip():
+        return ["--raw"]
+    return ["--raw"] if "--raw" in help_text else []
+
+
 class MeetingRecorder(QObject):
     """Microphone and speaker output into one stereo file: left is you, right is
     everyone else.

tests/test_audio.py

@@ -230,6 +230,23 @@ class RecordingCommand(DikteTest):
         with only_these_tools("pw-record"):
             self.assertEqual(audio.recording_command()[0], "pw-record")
 
+    def test_pw_record_uses_raw_when_the_installed_version_supports_it(self):
+        help_result = FakeCompleted(stdout="  --raw  Write raw samples\n")
+        with only_these_tools("pw-record"), \
+                mock.patch.object(audio.subprocess, "run", return_value=help_result):
+            self.assertIn("--raw", audio.recording_command())
+
+    def test_pw_record_omits_raw_when_pipewire_1_0_rejects_it(self):
+        help_result = FakeCompleted(stdout="  --rate  Sample rate\n")
+        with only_these_tools("pw-record"), \
+                mock.patch.object(audio.subprocess, "run", return_value=help_result):
+            self.assertNotIn("--raw", audio.recording_command())
+
+    def test_pw_record_help_failure_keeps_the_existing_command(self):
+        with only_these_tools("pw-record"), \
+                mock.patch.object(audio.subprocess, "run", side_effect=OSError):
+            self.assertIn("--raw", audio.recording_command())
+
     def test_neither_is_installed(self):
         with only_these_tools():
             self.assertEqual(audio.recording_command(), [])
@@ -282,6 +299,7 @@ class RecorderChain(DikteTest):
         recorder.failed.connect(failures.append)
         proc = FakeProcess(data)
         with only_these_tools("pw-record"), \
+                mock.patch.object(audio, "_pw_record_raw_option", return_value=[]), \
                 mock.patch.object(subprocess, "Popen", return_value=proc) as popen:
             recorder.start(target=target, max_seconds=max_seconds)
             recorder._thread.join(timeout=5)
@@ -328,6 +346,7 @@ class RecorderChain(DikteTest):
         recorder.stopped.connect(lambda *args: results.append(args))
         proc = FakeProcess(tone(1.0))
         with only_these_tools("pw-record"), \
+                mock.patch.object(audio, "_pw_record_raw_option", return_value=[]), \
                 mock.patch.object(subprocess, "Popen", return_value=proc):
             recorder.start()
             recorder._thread.join(timeout=5)