Fix PulseAudio readiness and scope ffmpeg audio tuning

Author: cursoragent

server/cmd/wrapper/main.go

@@ -188,6 +188,7 @@ func main() {
 		startAll("mutter")
 	}
 	waitForSocket(pulseSocket, 10*time.Second)
+	waitForPulseSink(os.Getenv("PULSE_SINK"), 10*time.Second)
 	startAll("chromium")
 	waitForSocket(dbusSocket, 10*time.Second)
 	if prof == profileHeadful && webrtc {
@@ -332,3 +333,21 @@ func fatalf(format string, args ...any) {
 	logf(format, args...)
 	os.Exit(1)
 }
+
+func waitForPulseSink(sinkName string, timeout time.Duration) {
+	sinkName = strings.TrimSpace(sinkName)
+	if sinkName == "" {
+		logf("WARNING: pulse sink name is empty; skipping sink wait")
+		return
+	}
+
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		out, err := exec.Command("pactl", "-s", "unix:"+pulseSocket, "list", "short", "sinks").Output()
+		if err == nil && strings.Contains(string(out), "\t"+sinkName+"\t") {
+			return
+		}
+		time.Sleep(50 * time.Millisecond)
+	}
+	logf("WARNING: pulse sink %s not ready after %s", sinkName, timeout)
+}

server/lib/recorder/ffmeg_test.go

@@ -2,6 +2,7 @@ package recorder
 
 import (
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -113,6 +114,20 @@ func TestFFmpegArgs_IncludesPulseAudioWhenEnabled(t *testing.T) {
 	assert.NotContains(t, args, "aresample=async=1:first_pts=0")
 }
 
+func TestFFmpegArgs_VideoOnlyLinuxUsesWallclockTimestamps(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("linux-only ffmpeg flag behavior")
+	}
+
+	tempDir := t.TempDir()
+	args, err := ffmpegArgs(defaultParams(tempDir), filepath.Join(tempDir, "out.mp4"))
+	require.NoError(t, err)
+
+	assert.Contains(t, args, "-use_wallclock_as_timestamps")
+	assert.NotContains(t, args, "veryfast")
+	assert.NotContains(t, args, "zerolatency")
+}
+
 func TestFFmpegRecorder_ForceStop(t *testing.T) {
 	tempDir := t.TempDir()
 	rec := &FFmpegRecorder{

server/lib/recorder/ffmpeg.go

@@ -563,11 +563,15 @@ func ffmpegArgs(params FFmpegRecordingParams, outputPath string) ([]string, erro
 
 		// Video encoding
 		"-c:v", "libx264",
-		"-preset", "veryfast",
-		"-tune", "zerolatency",
 		"-profile:v", "high", // Explicit web-compatible profile
 		"-pix_fmt", "yuv420p", // Web-standard pixel format
 	}...)
+	if runtime.GOOS == "linux" && recordAudio {
+		args = append(args,
+			"-preset", "veryfast",
+			"-tune", "zerolatency",
+		)
+	}
 
 	if recordAudio {
 		args = append(args, []string{
@@ -577,6 +581,9 @@ func ffmpegArgs(params FFmpegRecordingParams, outputPath string) ([]string, erro
 			"-ac", "2",
 		}...)
 	}
+	if runtime.GOOS == "linux" && !recordAudio {
+		args = append(args, "-use_wallclock_as_timestamps", "1")
+	}
 
 	args = append(args, []string{
 		// Timestamp handling for reliable playback