Record replay audio

[rgarcia]

Summary

• add optional audio capture to ffmpeg replay recordings using the PulseAudio output monitor
• start a shared PulseAudio null sink in the browser images and keep the monitor active with a silent sink input
• keep audio aligned through the full recording by avoiding forced audio PTS reset and using faster low-latency x264 encoding so ffmpeg does not fall behind real time
• add e2e coverage that records browser audio, downloads the MP4, verifies an audio track, checks the audio stream duration reaches the end of the recording, and includes a Zombocom archive sample recording

Tests

• go test ./lib/recorder -count=1
• DOCKER_BUILDKIT=1 docker build -f images/chromium-headful/Dockerfile -t onkernel/chromium-headful-test:latest .
• TESTCONTAINERS_RYUK_DISABLED=true TESTCONTAINERS_HOST_OVERRIDE=127.0.0.1 RECORDING_ZOMBO_OUTPUT_PATH=/home/agent/repos/kernel-images/server/e2e/testdata/replay-audio-zombocom.mp4 go test ./e2e -run 'TestReplayRecording(IncludesAudioTrack|ZombocomArchiveAudio)' -count=1 -v

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

Autofix Details

Bugbot Autofix prepared a fix for the issue found in the latest run.

• ✅ Fixed: Recording cap shorter than script
  • I made the recording duration configurable per test and increased the Zombocom archive scenario cap to 70 seconds so recording no longer ends before the Playwright flow completes.

Or push these changes by commenting:

@cursor push 2f6a9b26ef

Preview (2f6a9b26ef)

diff --git a/server/e2e/e2e_recording_audio_test.go b/server/e2e/e2e_recording_audio_test.go
--- a/server/e2e/e2e_recording_audio_test.go
+++ b/server/e2e/e2e_recording_audio_test.go
@@ -52,7 +52,7 @@
 		return await page.title();
 	`, audioSite.ContainerURL())
 
-	recordReplayAudio(t, ctx, c, playwrightCode, os.Getenv("RECORDING_AUDIO_OUTPUT_PATH"), 0.1)
+	recordReplayAudio(t, ctx, c, playwrightCode, os.Getenv("RECORDING_AUDIO_OUTPUT_PATH"), 35, 0.1)
 }
 
 func TestReplayRecordingZombocomArchiveAudio(t *testing.T) {
@@ -132,16 +132,15 @@
 		return playback;
 	`
 
-	recordReplayAudio(t, ctx, c, playwrightCode, outputPath, 0.01)
+	recordReplayAudio(t, ctx, c, playwrightCode, outputPath, 70, 0.01)
 }
 
-func recordReplayAudio(t *testing.T, ctx context.Context, c *TestContainer, playwrightCode string, outputPath string, minPeakLevel float64) {
+func recordReplayAudio(t *testing.T, ctx context.Context, c *TestContainer, playwrightCode string, outputPath string, maxDuration int, minPeakLevel float64) {
 	t.Helper()
 
 	client, err := c.APIClient()
 	require.NoError(t, err, "failed to create API client")
 
-	maxDuration := 35
 	maxFileSize := 100
 	startResp, err := client.StartRecordingWithResponse(ctx, instanceoapi.StartRecordingJSONRequestBody{
 		MaxDurationInSeconds: &maxDuration,

_{You can send follow-ups to the cloud agent here.}

[cursor]

Recording cap shorter than script

Medium Severity

recordReplayAudio caps ffmpeg at 35 seconds while the Zombocom Playwright script can run ~50+ seconds (30s selector timeout plus 20s of fixed waits). Recording stops mid-script, so the MP4 may omit most playback and audio checks can fail or pass on noise despite a successful browser run.

Additional Locations (1)

• server/e2e/e2e_recording_audio_test.go#L81-L133

 

^{Reviewed by Cursor Bugbot for commit ee7fb17. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

There are 3 total unresolved issues (including 1 from previous review).

Bugbot Autofix prepared fixes for both issues found in the latest run.

• ✅ Fixed: Pulse socket before sink ready
  • I load module-null-sink before module-native-protocol-unix so the Pulse socket appears only after KernelOutput is created.
• ✅ Fixed: Keepalive exit kills PulseAudio
  • I replaced wait -n with a keepalive retry loop and wait only on PulseAudio so a pacat exit no longer terminates the daemon.

Or push these changes by commenting:

@cursor push 8197b93a61

Preview (8197b93a61)

diff --git a/shared/start-pulseaudio.sh b/shared/start-pulseaudio.sh
--- a/shared/start-pulseaudio.sh
+++ b/shared/start-pulseaudio.sh
@@ -22,16 +22,12 @@
     --daemonize=no \
     --log-target=stderr \
     --exit-idle-time=-1 \
-    --load="module-native-protocol-unix socket=/tmp/pulse/native auth-anonymous=1" \
-    --load="module-null-sink sink_name=KernelOutput rate=48000 channels=2 sink_properties=device.description=KernelOutput" &
+    --load="module-null-sink sink_name=KernelOutput rate=48000 channels=2 sink_properties=device.description=KernelOutput" \
+    --load="module-native-protocol-unix socket=/tmp/pulse/native auth-anonymous=1" &
 
   pulse_pid=$!
-  keepalive_pid=""
 
   cleanup() {
-    if [ -n "$keepalive_pid" ]; then
-      kill "$keepalive_pid" 2>/dev/null || true
-    fi
     kill "$pulse_pid" 2>/dev/null || true
     wait 2>/dev/null || true
   }
@@ -44,10 +40,12 @@
     sleep 0.1
   done
 
-  (
-    pacat --raw --rate=48000 --channels=2 --format=s16le --device=KernelOutput /dev/zero
-  ) &
-  keepalive_pid=$!
+  while kill -0 "$pulse_pid" 2>/dev/null; do
+    pacat --raw --rate=48000 --channels=2 --format=s16le --device=KernelOutput /dev/zero || true
+    if kill -0 "$pulse_pid" 2>/dev/null; then
+      sleep 0.1
+    fi
+  done
 
-  wait -n "$pulse_pid" "$keepalive_pid"
+  wait "$pulse_pid"
   '

_{You can send follow-ups to the cloud agent here.}

^{Reviewed by Cursor Bugbot for commit f416d9d. Configure here.}

[cursor]

Pulse socket before sink ready

Medium Severity

Backgrounding pulseaudio exposes the Unix socket as soon as the protocol module loads, while KernelOutput may still be registering. The container wrapper only waits for the socket file, then starts Chromium with PULSE_SINK=KernelOutput, so the browser can launch before that sink exists and miss early replay audio.

 

^{Reviewed by Cursor Bugbot for commit f416d9d. Configure here.}

[cursor]

Keepalive exit kills PulseAudio

Medium Severity

The script uses wait -n on both pulseaudio and the pacat keepalive, and the EXIT trap always kills pulse_pid. If pacat exits while pulseaudio is still healthy, cleanup terminates the daemon and the whole supervisord program exits, causing an unnecessary audio stack restart.

 

^{Reviewed by Cursor Bugbot for commit f416d9d. Configure here.}