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Troubleshooting ​

Common issues and their solutions for Runtime Video Recorder.

Recording Issues ​

Recording Doesn't Start ​

Symptoms:

  • StartRecording() returns false
  • No error message in logs
  • Nothing happens when trying to record

Solutions:

  1. Check if already recording

    cpp
    if (Recorder->IsRecordingInProgress())
{
    UE_LOG(LogTemp, Warning, TEXT("Already recording!"));
}

  2. Verify output directory exists

    cpp
    // Plugin won't create directories
// Either use %auto% or ensure directory exists
FString OutPath = TEXT("E:/MyVideos/recording.mp4");
FString Directory = FPaths::GetPath(OutPath);

if (!FPaths::DirectoryExists(Directory))
{
    FPlatformFileManager::Get().GetPlatformFile().CreateDirectoryTree(*Directory);
}

  3. Check required plugins are enabled

    • Edit → Plugins
    • Verify ElectraPlayer is enabled
    • Verify AudioCapture is enabled (for audio recording)

  4. Check Output Log for errors

    • Open Output Log window
    • Filter by "RuntimeVideoRecorder"
    • Look for initialization errors

Recording Starts But No File Is Created ​

Symptoms:

  • StartRecording() returns true
  • Recording appears to work
  • No MP4 file after stopping

Solutions:

  1. Wait for encoding to finish

    cpp
    // Use the latent StopRecording in Blueprint, OR
// In C++, check status after stopping:
Recorder->StopRecording_NativeAPI();

// Wait for completion (in a timer or tick)
if (!Recorder->IsRecordingInProgress())
{
    FString Path = Recorder->GetLastRecordingFilepath();
    // File should now exist
}

  2. Check disk space

    • Ensure you have enough free space (100 MB+ per minute @ 1080p)
    • Check if drive is write-protected

  3. Verify file permissions

    • Ensure the application has write access to the output directory
    • On Windows: Check antivirus isn't blocking writes
    • On macOS: Grant app permissions in System Preferences

Quality Issues ​

Poor Video Quality / Blocky Artifacts ​

Solutions:

  1. Increase bitrate

    cpp
    FRuntimeEncoderSettings Settings;
Settings.VideoBitrate = 30000000;  // 30 Mbps (was 20)
Settings.TargetQuality = 80;       // Higher quality

  2. Use High profile

    cpp
    Settings.Profile = ERuntimeEncoderProfile::Profile_High;

  3. Use Quality rate control mode

    cpp
    Settings.RCMode = ERuntimeEncoderRCMode::RC_Quality;

  4. Reduce keyframe interval (for high-motion content)

    cpp
    Settings.KEYFRAME_INTERVAL = 15;  // More keyframes

  5. Check source resolution matches video resolution

    • Don't upscale: If viewport is 1280×720, don't record at 1920×1080
    • Match or downscale only

Video Quality Is Too Good (Files Too Large) ​

Solutions:

  1. Reduce bitrate

    cpp
    Settings.VideoBitrate = 10000000;  // 10 Mbps (was 20)

  2. Reduce resolution

    cpp
    Recorder->StartRecording(
    TEXT("%auto%"),
    30,
    1280, 720,  // 720p instead of 1080p
    Settings
);

  3. Increase keyframe interval

    cpp
    Settings.KEYFRAME_INTERVAL = 60;  // Fewer keyframes

Audio Issues ​

No Audio in Video ​

Solutions:

  1. Verify audio is enabled

    cpp
    bool bEnableAudio = true;  // Must be true
Recorder->StartRecording(TEXT("%auto%"), 30, -1, -1, Settings, true, bEnableAudio);

  2. Check frame-rate independent mode is OFF

    cpp
    bool bFrameRateIndependent = false;  // Audio doesn't work with true

    WARNING

    Audio recording is disabled in frame-rate independent mode!

  3. Verify AudioCapture plugin is enabled

    • Edit → Plugins → Search "Audio Capture"
    • Must be enabled

  4. Check audio device settings

    • Edit → Project Settings → Audio
    • Ensure valid audio output device is selected
    • Test audio in PIE (should hear game sounds)

  5. Linux: Audio not supported

    • Audio recording is not available on Linux
    • This is a known limitation

Audio Out of Sync with Video ​

Solutions:

  1. Ensure stable frame rate

    • Audio sync depends on consistent frame pacing
    • Cap frame rate if experiencing drops:
      cpp
      // In Project Settings → Engine → General Settings
// Set Frame Rate Limit to your target FPS

  2. Disable frame-rate independent mode

    cpp
    bool bFrameRateIndependent = false;

  3. Use lower recording FPS if game can't maintain it

    cpp
    // If game runs at 30 FPS, don't record at 60 FPS
Recorder->StartRecording(TEXT("%auto%"), 30, ...);  // Match game FPS

Performance Issues ​

Game Lags/Stutters While Recording ​

Solutions:

  1. Enable hardware acceleration (should be on by default)

    • Edit → Project Settings → Plugins → RuntimeVideoRecorder
    • Check Use Hardware Acceleration is enabled

  2. Lower video resolution

    cpp
    Recorder->StartRecording(
    TEXT("%auto%"),
    30,
    1280, 720,  // Lower than 1920×1080
    Settings
);

  3. Reduce target FPS

    cpp
    Recorder->StartRecording(TEXT("%auto%"), 30, ...);  // 30 instead of 60

  4. Disable debug frame dumping

    • Project Settings → RuntimeVideoRecorder
    • Ensure Debug Dump Each Frame is OFF

  5. Use on-the-fly encoding (not deferred)

    cpp
    bool bPostponeEncoding = false;  // Default

  6. Check GPU/CPU usage

    • Open Task Manager (Windows) or Activity Monitor (macOS)
    • If CPU is maxed: Lower resolution/FPS or enable hardware acceleration
    • If GPU is maxed: Reduce graphics settings or resolution

High CPU Usage (Windows) ​

Solutions:

  1. Verify hardware acceleration is working

    • Check Output Log for "Using hardware encoder" message
    • If using software encoder, check GPU drivers

  2. Force hardware acceleration for all vendors (AMD/Intel)

    • Project Settings → RuntimeVideoRecorder
    • Enable Force Hardware Acceleration For All Vendors

  3. Update GPU drivers

    • NVIDIA: Download from nvidia.com
    • AMD: Download from amd.com
    • Intel: Download from intel.com

High Memory Usage ​

Symptoms:

  • Memory usage grows significantly during recording
  • Potential out-of-memory crashes

Solutions:

  1. Avoid deferred encoding

    cpp
    bool bPostponeEncoding = false;  // Don't use true for long recordings

    DANGER

    Deferred encoding stores ALL frames in RAM before encoding. Only use for short (<30 sec) recordings!

  2. Limit circular buffer duration

    cpp
    // Don't use long circular buffers
float LastSecondsToRecord = 30.0f;  // 30 sec max, not 600

  3. Lower resolution

    • 1080p uses 4× more memory than 720p
    • 4K uses 4× more memory than 1080p

Platform-Specific Issues ​

Windows ​

Hardware Acceleration Not Working ​

Solutions:

  1. Update GPU drivers (most common cause)

  2. Enable for all vendors

    • Project Settings → RuntimeVideoRecorder
    • Check Force Hardware Acceleration For All Vendors

  3. Check GPU compatibility

    • Very old GPUs may not support H.264 encoding
    • Minimum: NVIDIA Kepler (GTX 600), AMD GCN 1.0, Intel HD 4000

  4. Verify no other app is using encoder

    • Some GPUs have limited encoder sessions
    • Close other recording software (OBS, ShadowPlay, etc.)

macOS ​

Black Screen in Recording ​

Solutions:

  1. Grant screen recording permission

    • System Preferences → Security & Privacy → Screen Recording
    • Add Unreal Engine/your app to allowed list

  2. Check camera permission (for camera recording)

    • System Preferences → Security & Privacy → Camera
    • Grant permission if prompted

Linux ​

Very High CPU Usage ​

Expected Behavior:

  • Linux uses OpenH264 software encoding (no hardware acceleration)
  • High CPU usage is normal

Solutions:

  1. Lower resolution/FPS

    cpp
    Recorder->StartRecording(TEXT("%auto%"), 24, 1280, 720, ...);

  2. Reduce bitrate

    cpp
    Settings.VideoBitrate = 8000000;  // 8 Mbps

  3. Use simpler encoder settings

    cpp
    Settings.Profile = ERuntimeEncoderProfile::Profile_Baseline;
Settings.TargetQuality = 40;

Android ​

Recording Not Starting on Device ​

Solutions:

  1. Check storage permissions

    • Ensure WRITE_EXTERNAL_STORAGE permission is granted
    • Add to Config/DefaultEngine.ini:
      ini
      [/Script/AndroidRuntimeSettings.AndroidRuntimeSettings]
bEnablePermission_WRITE_EXTERNAL_STORAGE=True

  2. Verify device supports MediaCodec

    • Most devices Android 5.0+ support it
    • Some very old devices may not

  3. Check available storage

    • Device must have sufficient free space

  4. Use lower resolution for mobile

    cpp
    Recorder->StartRecording(TEXT("%auto%"), 30, 1280, 720, ...);

Hardware Encoding Not Available ​

Solutions:

  1. Check device capabilities

    • Not all Android devices support hardware H.264 encoding
    • Emulators often don't support it

  2. Update device firmware

    • Some manufacturers add codec support in updates

Oculus/Meta Quest ​

Recording Causes Frame Drops in VR ​

Solutions:

  1. Use lower resolution

    cpp
    Recorder->StartRecording(TEXT("%auto%"), 30, 1280, 720, ...);

  2. Enable low-latency mode

    cpp
    Settings.WIN_bUseLowLatencyEncoding = true;  // If on Windows backend

  3. Record at 30 FPS (not 72/90)

    cpp
    Recorder->StartRecording(TEXT("%auto%"), 30, ...);

Compilation & Build Issues ​

"Module RuntimeVideoRecorder not found" ​

Solutions:

  1. Add to Build.cs

    csharp
    PublicDependencyModuleNames.AddRange(new string[] {
    "RuntimeVideoRecorder"
});

  2. Regenerate project files

    • Right-click .uproject → Generate Visual Studio project files

  3. Clean and rebuild

    • Delete Binaries and Intermediate folders
    • Rebuild solution

Android Build Fails ​

Solutions:

  1. Check NDK version

    • Minimum NDK r21
    • Update in Android Studio

  2. Verify SDK version

    • Minimum SDK 21
    • Target SDK 30+

  3. Check Android settings in Project Settings

    • Packaging → Android → Package for arm64

Crash Issues ​

Crash on StartRecording ​

Solutions:

  1. Check Output Log for error messages before crash

  2. Verify output path is valid

    cpp
    // Use %auto% for testing
Recorder->StartRecording(TEXT("%auto%"), ...);

  3. Update GPU drivers (Windows)

  4. Try software encoding

    • Project Settings → RuntimeVideoRecorder
    • Disable Use Hardware Acceleration temporarily

Crash on StopRecording ​

Solutions:

  1. Don't call StopRecording multiple times

    cpp
    if (Recorder->IsRecordingInProgress())
{
    Recorder->StopRecording_NativeAPI();
}

  2. Wait for previous recording to finish

    • Don't start new recording immediately after stopping

Still Having Issues? ​

Get Help ​

  1. Join Discord for quick community support

  2. Check Output Log

    • Copy relevant error messages
    • Include in your support request

  3. Provide Information

    • Unreal Engine version
    • Platform (Windows/Mac/Linux/Android)
    • GPU model and driver version
    • Code snippet or Blueprint screenshot
    • Error messages from Output Log

  4. Email Support

See Also ​

Released under the MIT License.

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