FRuntimeEncoderSettings

Configuration structure for video encoding parameters.

Structure Definition

USTRUCT(BlueprintType)
struct FRuntimeEncoderSettings
{
    GENERATED_BODY()

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    int32 VideoBitrate = 20000000;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    ERuntimeEncoderProfile Profile = ERuntimeEncoderProfile::Profile_Main;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    ERuntimeEncoderRCMode RCMode = ERuntimeEncoderRCMode::RC_Quality;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    int32 TargetQuality = 50;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    int32 WIN_QualityVsSpeed = 50;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    bool WIN_bUseLowLatencyEncoding = false;

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    int32 KEYFRAME_INTERVAL = 30;
};

---

Properties

VideoBitrate

Output video bitrate in bits per second.

Type: int32
Default: 20000000 (20 Mbps)

Recommended Values:

• 720p (1280×720): 5,000,000 - 10,000,000 (5-10 Mbps)
• 1080p (1920×1080): 10,000,000 - 20,000,000 (10-20 Mbps)
• 1440p (2560×1440): 20,000,000 - 40,000,000 (20-40 Mbps)
• 4K (3840×2160): 40,000,000 - 80,000,000 (40-80 Mbps)

TIP

Higher bitrate = better quality but larger file size. Use RC_Quality mode for better quality-to-size ratio.

Example

FRuntimeEncoderSettings Settings;
Settings.VideoBitrate = 30000000;  // 30 Mbps for high-quality 1080p

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Profile

H.264 encoder profile.

Type: ERuntimeEncoderProfile
Default: Profile_Main

Options:

• Profile_Baseline - Maximum compatibility, lowest quality
• Profile_Main - Good balance (recommended)
• Profile_High - Best quality, requires modern devices

Compatibility

Profile_High may not be compatible with older mobile devices or some web players. Use Profile_Main for maximum compatibility.

Example

Settings.Profile = ERuntimeEncoderProfile::Profile_High;  // Best quality

---

RCMode

Rate control mode.

Type: ERuntimeEncoderRCMode
Default: RC_Quality

Options:

• RC_Bitrate - Constant bitrate (predictable file sizes)
• RC_Quality - Variable bitrate (better quality per file size)

When to Use:

• Use RC_Bitrate for consistent file sizes, streaming
• Use RC_Quality for best quality recordings (recommended)

Example

Settings.RCMode = ERuntimeEncoderRCMode::RC_Quality;  // Variable bitrate

---

TargetQuality

Encoding quality target (0-100).

Type: int32
Default: 50
Range: 0 (lowest) to 100 (highest)

Recommended Values:

• Low Quality: 30-40
• Medium Quality: 50-60 (default)
• High Quality: 70-85
• Very High Quality: 90-100

INFO

This setting is most effective when using RC_Quality mode. In RC_Bitrate mode, the encoder tries to maintain constant bitrate regardless.

Example

Settings.TargetQuality = 85;  // High quality

---

WIN_QualityVsSpeed

Windows-specific: Trade-off between encoding quality and speed.

Type: int32
Default: 50
Range: 0 (fastest) to 100 (best quality)
Platform: Windows only (ignored on other platforms)

Values:

• 0-30: Prioritize speed (faster encoding, lower quality)
• 30-70: Balanced
• 70-100: Prioritize quality (slower encoding, better quality)

Real-Time Recording

For real-time gameplay recording, keep this at 50 or lower. Higher values may cause encoding to fall behind capture rate.

Example

Settings.WIN_QualityVsSpeed = 30;  // Faster encoding for real-time

---

WIN_bUseLowLatencyEncoding

Windows-specific: Enable low-latency encoding mode.

Type: bool
Default: false
Platform: Windows only

When to Enable:

• Real-time communications
• Live streaming
• VR applications requiring minimal latency

Trade-offs:

• ✅ Lower encoding latency
• ❌ Potentially reduced quality
• ❌ Slightly larger file sizes

WARNING

Low-latency mode may reduce overall quality. Only enable if latency is critical for your use case.

Example

Settings.WIN_bUseLowLatencyEncoding = true;  // For VR/live streaming

---

KEYFRAME_INTERVAL

Number of frames between keyframes (I-frames).

Type: int32
Default: 30

Recommended Values:

• Low Motion: 60-120 (smaller files)
• Normal Gameplay: 30-60 (balanced)
• High Motion/Action: 15-30 (better seeking)
• Streaming: 60-120 (better compression)

What are Keyframes? Keyframes are full frames in the video. Frames between keyframes are delta (difference) frames. More frequent keyframes = better seeking ability but larger file size.

Example

Settings.KEYFRAME_INTERVAL = 60;  // Keyframe every 60 frames (every 2 sec @ 30fps)

---

Preset Configurations

Low Quality (Small Files)

FRuntimeEncoderSettings LowQuality;
LowQuality.VideoBitrate = 5000000;      // 5 Mbps
LowQuality.Profile = ERuntimeEncoderProfile::Profile_Baseline;
LowQuality.RCMode = ERuntimeEncoderRCMode::RC_Bitrate;
LowQuality.TargetQuality = 30;
LowQuality.WIN_QualityVsSpeed = 20;
LowQuality.KEYFRAME_INTERVAL = 60;

Use Case: Mobile recording, low storage space

---

Balanced Quality (Recommended)

FRuntimeEncoderSettings Balanced;
Balanced.VideoBitrate = 20000000;       // 20 Mbps
Balanced.Profile = ERuntimeEncoderProfile::Profile_Main;
Balanced.RCMode = ERuntimeEncoderRCMode::RC_Quality;
Balanced.TargetQuality = 60;
Balanced.WIN_QualityVsSpeed = 50;
Balanced.KEYFRAME_INTERVAL = 30;

Use Case: General gameplay recording, good quality-to-size ratio

---

High Quality (Large Files)

FRuntimeEncoderSettings HighQuality;
HighQuality.VideoBitrate = 40000000;    // 40 Mbps
HighQuality.Profile = ERuntimeEncoderProfile::Profile_High;
HighQuality.RCMode = ERuntimeEncoderRCMode::RC_Quality;
HighQuality.TargetQuality = 85;
HighQuality.WIN_QualityVsSpeed = 70;
HighQuality.KEYFRAME_INTERVAL = 30;

Use Case: Cinematic recordings, trailers, marketing content

---

Streaming / Live

FRuntimeEncoderSettings Streaming;
Streaming.VideoBitrate = 6000000;       // 6 Mbps
Streaming.Profile = ERuntimeEncoderProfile::Profile_Main;
Streaming.RCMode = ERuntimeEncoderRCMode::RC_Bitrate;
Streaming.TargetQuality = 50;
Streaming.WIN_QualityVsSpeed = 30;
Streaming.WIN_bUseLowLatencyEncoding = true;
Streaming.KEYFRAME_INTERVAL = 60;

Use Case: Live streaming, real-time communications

---

VR Recording

FRuntimeEncoderSettings VR;
VR.VideoBitrate = 30000000;             // 30 Mbps
VR.Profile = ERuntimeEncoderProfile::Profile_High;
VR.RCMode = ERuntimeEncoderRCMode::RC_Quality;
VR.TargetQuality = 75;
VR.WIN_QualityVsSpeed = 40;             // Balance speed for VR
VR.WIN_bUseLowLatencyEncoding = true;   // Reduce latency
VR.KEYFRAME_INTERVAL = 30;

Use Case: VR gameplay capture, 360° video

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Platform Differences

Windows (WMF)

Supports:

• All settings fully supported
• Hardware acceleration (NVIDIA, AMD, Intel)
• WIN_QualityVsSpeed and WIN_bUseLowLatencyEncoding are Windows-specific

Recommended:

Settings.VideoBitrate = 20000000;
Settings.Profile = ERuntimeEncoderProfile::Profile_High;
Settings.WIN_QualityVsSpeed = 50;

---

macOS (AVFoundation)

Supports:

• All settings except Windows-specific ones
• Hardware acceleration (VideoToolbox)

Recommended:

Settings.VideoBitrate = 20000000;
Settings.Profile = ERuntimeEncoderProfile::Profile_Main;

---

Android (MediaCodec)

Supports:

• Basic settings (bitrate, profile, quality)
• Hardware acceleration (device-dependent)

Recommended:

Settings.VideoBitrate = 10000000;       // Lower for mobile
Settings.Profile = ERuntimeEncoderProfile::Profile_Main;
Settings.TargetQuality = 60;

Mobile Performance

Use lower bitrates and resolutions on mobile to avoid performance issues.

---

Linux (OpenH264)

Supports:

• Basic settings only
• Software encoding (no hardware acceleration)

Recommended:

Settings.VideoBitrate = 15000000;
Settings.Profile = ERuntimeEncoderProfile::Profile_Baseline;
Settings.TargetQuality = 50;

Software Encoding

Linux uses CPU encoding. Expect higher CPU usage. Consider lower resolutions/bitrates.

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Calculating File Sizes

Formula: File Size (MB) ≈ (Bitrate / 8) × Duration (seconds) / 1,000,000

Examples:

Bitrate	Resolution	1 Minute	5 Minutes	10 Minutes
5 Mbps	720p	~37 MB	~187 MB	~375 MB
10 Mbps	1080p	~75 MB	~375 MB	~750 MB
20 Mbps	1080p	~150 MB	~750 MB	~1.5 GB
40 Mbps	4K	~300 MB	~1.5 GB	~3 GB

Storage Planning

1 hour of 1080p@20Mbps ≈ 9 GB. Plan storage accordingly for long recordings!

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See Also

• URuntimeVideoRecorder - Main API reference
• Quick Start - Getting started guide
• How-To Guide - Practical recording scenarios
• Troubleshooting - Common issues and solutions