Quality Settings

Frame offers two primary quality control modes: CRF (Constant Rate Factor) for quality-based encoding and Target Bitrate for size-based encoding. This guide explains how each mode works and when to use them.

Quality Control Modes

CRF Mode
Bitrate Mode

CRF (Constant Rate Factor)

Mode: videoBitrateMode: "crf"CRF is a quality-based encoding mode that maintains consistent visual quality throughout the video, allowing the bitrate to vary as needed.

How CRF Works

CRF uses a scale where lower numbers = higher quality:For Software Encoders (H.264/H.265):

0 - Lossless (massive file sizes)
17-18 - Visually lossless (archival quality)
19-23 - High quality (recommended)
23-28 - Medium quality (default)
29-34 - Low quality (web/streaming)
35+ - Very low quality (avoid)

CRF Scale Reference

CRF Value	Quality Level	Use Case	Approx. File Size*
18	Visually Lossless	Archival, mastering	100% (baseline)
20	Excellent	High-quality delivery	70%
23	Good	Default - General use	50%
26	Acceptable	Streaming, web	35%
28	Fair	Low-bandwidth streaming	25%
30	Poor	Web previews only	18%

*Relative to CRF 18. Actual sizes vary by content.

Frame’s CRF Configuration

{
  "videoBitrateMode": "crf",
  "crf": 23
}

The crf field accepts values 0-51:

Default: 23 (balanced quality)
Archival: 18-20
Web: 28-30

Benefits of CRF

Consistent quality across all scenes
Efficient encoding - allocates bits where needed
Predictable quality - same CRF = same visual quality
Variable bitrate - simple scenes use fewer bits

Drawbacks of CRF

Unpredictable file size - varies by content complexity
Can’t target specific file size

CRF is the recommended mode for most use cases. It provides the best quality-to-size ratio and is used by all of Frame’s built-in presets.

Content-Specific CRF Guidance

Animation/Simple Graphics:

Very efficient compression
Use CRF 20-24 for excellent quality
Files will be relatively small

Live Action/Complex Scenes:

Requires higher bitrate
Use CRF 18-22 for excellent quality
Files will be larger

Screen Recordings/Text:

Text can look blurry at high CRF
Use CRF 18-20 for sharp text
Consider lossless (CRF 0) for critical detail

Target Bitrate

Mode: videoBitrateMode: "bitrate"Target bitrate mode encodes at a specific bitrate, allowing you to predict and control file sizes.

How Bitrate Mode Works

You specify a target bitrate in kilobits per second (kbps), and the encoder adjusts quality to maintain that bitrate.

Bitrate Recommendations

1080p (1920x1080) @ 30fps:

2,500 kbps - Low quality (web streaming)
5,000 kbps - Good quality (general use)
8,000 kbps - High quality (YouTube recommended)
10,000 kbps - Very high quality

720p (1280x720) @ 30fps:

1,000 kbps - Low quality
2,500 kbps - Good quality
5,000 kbps - High quality

4K (3840x2160) @ 30fps:

20,000 kbps - Good quality
35,000-45,000 kbps - YouTube recommended
60,000+ kbps - High quality archival

Frame’s Bitrate Configuration

{
  "videoBitrateMode": "bitrate",
  "videoBitrate": "5000"
}

The videoBitrate field specifies the target in kbps.

Benefits of Bitrate Mode

Predictable file size - easy to calculate
Meeting platform requirements (YouTube, TikTok, etc.)
Bandwidth constraints - stay under limits

Drawbacks of Bitrate Mode

Variable quality - simple scenes look better, complex scenes worse
Inefficient - wastes bits on simple scenes
May not meet quality needs for complex content

Calculating File Size

Formula:

File Size (MB) = (Video Bitrate + Audio Bitrate) × Duration (seconds) / 8000

Example: 1080p video, 5000 kbps video + 128 kbps audio, 10 minutes:

(5000 + 128) × 600 / 8000 = 384 MB

Use bitrate mode when you need predictable file sizes for platform requirements or storage constraints.

Platform-Specific Bitrate Targets

YouTube:

1080p: 8,000-10,000 kbps
4K: 35,000-45,000 kbps

TikTok/Instagram Reels:

1080x1920 portrait: 5,000-8,000 kbps

Twitter/X:

1080p: 2,000-3,000 kbps (low file size limits)

Discord:

Non-Nitro (8 MB limit): 500-1,500 kbps
Nitro (50 MB limit): 2,000-5,000 kbps

Hardware Encoder Quality

Hardware encoders (NVENC, VideoToolbox) use different quality systems than software encoders.

NVIDIA NVENC Quality

For h264_nvenc, hevc_nvenc, av1_nvenc: Frame uses the quality field (0-100) which maps to NVENC’s CQ (Constant Quality) parameter:

CQ = 52 - (quality / 2)

Quality Scale:

Quality 100 → CQ 1 (best quality, largest files)
Quality 80 → CQ 12 (excellent quality)
Quality 60 → CQ 22 (high quality)
Quality 50 → CQ 26 (balanced) - Default
Quality 40 → CQ 32 (acceptable quality)
Quality 20 → CQ 42 (low quality)
Quality 0 → CQ 51 (poor quality)

Recommended NVENC Quality Values

Quality Value	CQ	Use Case
65-70	17-19	High quality archival
50-60	22-26	General use, balanced
40-45	30-34	Web streaming
30-35	35-39	Low bandwidth

NVENC Configuration Example

{
  "videoCodec": "h264_nvenc",
  "videoBitrateMode": "crf",
  "quality": 50,
  "nvencSpatialAq": true,
  "nvencTemporalAq": true
}

NVENC quality ~50-55 is comparable to software CRF 23-25, providing good quality with 5-10x faster encoding.

Apple VideoToolbox Quality

For h264_videotoolbox, hevc_videotoolbox: VideoToolbox uses the quality field directly (0-100), where higher is better: Quality Scale:

Quality 100 - Maximum quality
Quality 70-80 - High quality
Quality 60 - Good quality
Quality 50 - Balanced - Default
Quality 40 - Acceptable
Quality 20-30 - Low quality
Quality 0 - Minimum quality

Quality Value	Use Case
70-80	Archival, high quality
50-60	General use, balanced
40-45	Web streaming
30-35	Low bandwidth

VideoToolbox Configuration Example

{
  "videoCodec": "h264_videotoolbox",
  "quality": 50,
  "hwDecode": true
}

VideoToolbox quality is opposite of CRF: higher numbers = better quality (not lower like software CRF).

Quality vs File Size Tradeoffs

Visual Quality Perception

Understanding diminishing returns in quality:

CRF 18 vs CRF 23 (Software)

File Size Difference: ~2x (CRF 18 is twice as large)Visual Difference: Minimal for most contentWhen the difference matters:

Color grading and post-production
Large displays (4K+ monitors)
Professional archival

When it doesn’t matter:

Web/mobile viewing
Standard displays
Casual playback

Recommendation: Use CRF 23 for general use, CRF 18-20 only for archival or professional work.

CRF 23 vs CRF 28 (Software)

File Size Difference: ~2x (CRF 28 is half the size)Visual Difference: Noticeable in complex scenesWhen CRF 28 is acceptable:

Small screen viewing (phones)
Low-motion content
Bandwidth-constrained delivery

When to avoid CRF 28:

High-motion content (sports, action)
Large screen playback
Complex/detailed scenes

Recommendation: CRF 23 is the sweet spot for most use cases.

Hardware vs Software Quality

File Size Difference: 10-20% larger with hardware at equivalent qualityEncoding Speed: 5-10x faster with hardwareVisual Quality: Very similar at recommended settingsRecommended settings for comparable quality:

Software: CRF 23
NVENC: Quality 50-55
VideoToolbox: Quality 50-55

Choose hardware when: Speed matters more than 10-20% file size savingsChoose software when: Smallest possible file size is critical

Content Complexity Impact

How different content types affect file size at the same quality setting: Animation/Simple Graphics (CRF 23):

Very few details, solid colors
File size: Small (1x baseline)
Compression efficiency: Excellent

Live Action/Medium Complexity (CRF 23):

Typical movies, TV shows
File size: Medium (2-3x animation)
Compression efficiency: Good

High Detail/Grain/Noise (CRF 23):

Film grain, nature footage, complex textures
File size: Large (4-5x animation)
Compression efficiency: Lower
May need CRF 18-20 for acceptable quality

Content complexity has a larger impact on file size than CRF adjustments. A 1080p animation at CRF 23 might be 500 MB, while nature footage at CRF 23 could be 2-3 GB.

Recommended Settings by Use Case

General Purpose
High Quality Archival
Web Streaming
Social Media

Balanced Quality/Size

For everyday video conversion and storage:Software Encoding (H.264):

{
  "videoCodec": "libx264",
  "videoBitrateMode": "crf",
  "crf": 23,
  "preset": "medium"
}

Hardware Encoding (NVENC):

{
  "videoCodec": "h264_nvenc",
  "videoBitrateMode": "crf",
  "quality": 50,
  "preset": "medium",
  "nvencSpatialAq": true
}

Expected Results:

Good quality for most viewing scenarios
Reasonable file sizes
Fast encoding (especially with hardware)

Maximum Quality

For long-term storage and archival:Software Encoding (H.265):

{
  "videoCodec": "libx265",
  "videoBitrateMode": "crf",
  "crf": 18,
  "preset": "slow"
}

Hardware Encoding (NVENC HEVC):

{
  "videoCodec": "hevc_nvenc",
  "videoBitrateMode": "crf",
  "quality": 65,
  "preset": "slow",
  "nvencSpatialAq": true,
  "nvencTemporalAq": true
}

Expected Results:

Visually lossless quality
Large file sizes (but compressed)
Slower encoding (especially software)
Future-proof for re-encoding

Bandwidth-Optimized

For web delivery and streaming:1080p Web:

{
  "videoCodec": "vp9",
  "videoBitrateMode": "crf",
  "crf": 30,
  "preset": "medium",
  "resolution": "1080p"
}

720p Web:

{
  "videoCodec": "libx264",
  "videoBitrateMode": "crf",
  "crf": 28,
  "preset": "medium",
  "resolution": "720p"
}

Expected Results:

Small file sizes
Fast streaming
Acceptable quality for web viewing

Platform Requirements

Meeting platform-specific requirements:YouTube 1080p:

{
  "videoCodec": "libx264",
  "videoBitrateMode": "bitrate",
  "videoBitrate": "10000",
  "preset": "slow",
  "resolution": "1080p",
  "audioCodec": "aac",
  "audioBitrate": "320"
}

TikTok/Reels (Portrait):

{
  "videoCodec": "libx264",
  "videoBitrateMode": "bitrate",
  "videoBitrate": "6000",
  "preset": "slow",
  "customWidth": "1080",
  "customHeight": "1920",
  "audioNormalize": true
}

Discord (Non-Nitro, 8MB limit):

{
  "videoCodec": "libx264",
  "videoBitrateMode": "bitrate",
  "videoBitrate": "1000",
  "preset": "veryfast",
  "resolution": "720p",
  "audioCodec": "aac",
  "audioBitrate": "64"
}

Quality Assessment Tips

Testing Your Settings

How to Validate Quality Settings

Encode a short clip (30-60 seconds)
Compare multiple quality settings side-by-side
View on target device (phone, TV, monitor)
Look for compression artifacts:
- Blockiness in gradients
- Blurriness in fine details
- Banding in solid colors
- Motion artifacts in fast movement

Quality Test Checklist:

Common Quality Mistakes

Avoid These Pitfalls

Using CRF Too High:

CRF 30+ for high-resolution content
Results in visible compression artifacts
Fix: Lower CRF to 23-26

Using CRF Too Low Unnecessarily:

CRF 15-18 for web/mobile delivery
Wastes storage with no visual benefit
Fix: Use CRF 23 for general use

Bitrate Mode for Archival:

Wastes bits on simple scenes
May starve complex scenes of quality
Fix: Use CRF mode for archival

Wrong Quality Parameter for Hardware:

Using crf field with hardware encoders
Fix: Use quality field for NVENC/VideoToolbox

Not Testing on Target Device:

Looks fine on 4K monitor, bad on phone
Fix: Always test where it will be viewed

Get Started

Features

Guides

Development

​Quality Settings

​Quality Control Modes

​CRF (Constant Rate Factor)

​How CRF Works

​CRF Scale Reference

​Frame’s CRF Configuration

​Benefits of CRF

​Drawbacks of CRF

​Content-Specific CRF Guidance

​Target Bitrate

​How Bitrate Mode Works

​Bitrate Recommendations

​Frame’s Bitrate Configuration

​Benefits of Bitrate Mode

​Drawbacks of Bitrate Mode

​Calculating File Size

​Platform-Specific Bitrate Targets

​Hardware Encoder Quality

​NVIDIA NVENC Quality

​Recommended NVENC Quality Values

​NVENC Configuration Example

​Apple VideoToolbox Quality

​Recommended VideoToolbox Quality Values

​VideoToolbox Configuration Example

​Quality vs File Size Tradeoffs

​Visual Quality Perception

​Content Complexity Impact

​Recommended Settings by Use Case

​Balanced Quality/Size

​Maximum Quality

​Bandwidth-Optimized

​Platform Requirements

​Quality Assessment Tips

​How to Validate Quality Settings

​Avoid These Pitfalls

​See Also

Build docs developers (and LLMs) love

Quality Settings

Quality Control Modes

CRF (Constant Rate Factor)

How CRF Works

CRF Scale Reference

Frame’s CRF Configuration

Benefits of CRF

Drawbacks of CRF

Content-Specific CRF Guidance

Target Bitrate

How Bitrate Mode Works

Bitrate Recommendations

Frame’s Bitrate Configuration

Benefits of Bitrate Mode

Drawbacks of Bitrate Mode

Calculating File Size

Platform-Specific Bitrate Targets

Hardware Encoder Quality

NVIDIA NVENC Quality

Recommended NVENC Quality Values

NVENC Configuration Example

Apple VideoToolbox Quality

Recommended VideoToolbox Quality Values

VideoToolbox Configuration Example

Quality vs File Size Tradeoffs

Visual Quality Perception

Content Complexity Impact

Recommended Settings by Use Case

Balanced Quality/Size

Maximum Quality

Bandwidth-Optimized

Platform Requirements

Quality Assessment Tips

How to Validate Quality Settings

Avoid These Pitfalls

See Also