Compression & Degradation Operations

Four operations provide comprehensive control over image degradation and compression artifacts. These operations are perfect for creating glitch art, simulating social media compression, and exploring digital decay.

Quick Reference

Operation Purpose Key Parameters
compression Single-pass JPEG compression quality, subsampling
multi_compress Multi-generation with decay iterations, decay curve
downscale Resolution reduction/pixelation scale, upscale_method
motion_blur Directional blur kernel_size, angle

Compression

Apply JPEG compression with configurable quality and chroma subsampling to create block artifacts and color banding.

Basic Usage 

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- name: "compress"
  operation: "compression"
  params:
    quality: 50         # 1-100 (lower = more artifacts)
    subsampling: 2      # 0 (4:4:4), 1 (4:2:2), or 2 (4:2:0)

Parameters

  • quality (int, 1-100): JPEG quality level
    • 1-15: Severe artifacts, visible 8x8 blocks
    • 16-50: Moderate compression, noticeable artifacts
    • 51-85: Subtle compression
    • 86-100: Minimal artifacts
  • subsampling (int, 0/1/2): Chroma subsampling mode
    • 0 (4:4:4): No subsampling - highest quality
    • 1 (4:2:2): Moderate subsampling
    • 2 (4:2:0): Heavy subsampling - creates visible 8x8 blocks (default)
  • optimize (bool, optional): Apply JPEG optimization (default: true)

Examples

Severe Compression:

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- name: "extreme_artifacts"
  operation: "compression"
  params:
    quality: 5
    subsampling: 2
    optimize: false

Social Media Quality:

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- name: "instagram_compression"
  operation: "compression"
  params:
    quality: 75
    subsampling: 2

Multi-Compress

Apply JPEG compression multiple times with quality decay to simulate multi-generation compression (like repeatedly saving/sharing images on social media).

Basic Usage 

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- name: "multi_gen"
  operation: "multi_compress"
  params:
    iterations: 5
    quality_start: 60
    quality_end: 20
    decay: "linear"
    subsampling: 2

Parameters

  • iterations (int, 1-50): Number of compression cycles
  • quality_start (int, 1-100): Starting quality level
  • quality_end (int, 1-100): Ending quality (must be < quality_start for decay modes)
  • decay (str): Quality decay type
    • "fixed": Same quality each iteration
    • "linear": Quality decreases evenly
    • "exponential": Rapid initial degradation, then levels off
  • subsampling (int, 0/1/2, optional): Chroma subsampling mode (default: 2)

Decay Curves

Linear Decay:

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iterations: 5, quality_start: 60, quality_end: 20
Step 1: quality 60
Step 2: quality 50
Step 3: quality 40
Step 4: quality 30
Step 5: quality 20

Exponential Decay:

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iterations: 5, quality_start: 60, quality_end: 20
Step 1: quality 60
Step 2: quality 42
Step 3: quality 32
Step 4: quality 26
Step 5: quality 20

(More degradation early, levels off)

Fixed Quality:

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iterations: 5, quality_start: 50 (quality_end ignored)
All 5 iterations use quality 50

Examples

Social Media Sharing Chain:

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- name: "viral_degradation"
  operation: "multi_compress"
  params:
    iterations: 4
    quality_start: 75
    quality_end: 45
    decay: "linear"

Glitch Art:

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- name: "extreme_decay"
  operation: "multi_compress"
  params:
    iterations: 12
    quality_start: 30
    quality_end: 5
    decay: "exponential"

Downscale

Reduce image resolution with configurable resampling methods to create pixelation effects.

Basic Usage 

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- name: "pixelate"
  operation: "downscale"
  params:
    scale: 0.25                 # 25% of original size
    upscale: true               # Scale back to original size
    downscale_method: "bicubic"
    upscale_method: "nearest"   # Harsh pixelation

Parameters

  • scale (float, 0.01-1.0): Scale factor
    • 0.01-0.10: Extreme pixelation
    • 0.10-0.25: Heavy pixelation
    • 0.25-0.50: Moderate pixelation
    • 0.50-1.00: Subtle quality reduction

  • upscale (bool, optional): Whether to upscale back to original size (default: true)

  • downscale_method (str, optional): Resampling for downscaling
    • Options: "nearest", "bilinear", "bicubic", "lanczos", "box"
    • Default: "bicubic"
  • upscale_method (str, optional): Resampling for upscaling
    • "nearest": Creates harsh, blocky pixelation
    • "bilinear": Softer pixelation
    • "bicubic", "lanczos": Smooth upscaling
    • Default: "bilinear"

Examples

Extreme Pixelation:

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- name: "mega_pixels"
  operation: "downscale"
  params:
    scale: 0.05
    upscale: true
    downscale_method: "bicubic"
    upscale_method: "nearest"

Retro Game Aesthetic:

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- name: "8bit_style"
  operation: "downscale"
  params:
    scale: 0.15
    upscale: true
    upscale_method: "nearest"

Soft Quality Reduction:

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- name: "subtle_blur"
  operation: "downscale"
  params:
    scale: 0.7
    upscale: true
    upscale_method: "bilinear"

Motion Blur

Apply directional motion blur to simulate camera movement, shake, or scan line effects.

Basic Usage 

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- name: "blur"
  operation: "motion_blur"
  params:
    kernel_size: 10
    angle: 45

Parameters

  • kernel_size (int, 1-100): Blur strength in pixels
    • 1-3: Minimal blur, subtle shake
    • 3-8: Moderate blur
    • 8-20: Heavy blur
    • 20-50: Very strong blur
    • 50-100: Extreme blur
  • angle (float, 0-360, optional): Direction of motion in degrees
    • 0: Horizontal (left-right)
    • 90: Vertical (up-down)
    • 45 / 135: Diagonal
    • Default: 0

Examples

VHS Scan Lines:

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- name: "scanlines"
  operation: "motion_blur"
  params:
    kernel_size: 7
    angle: 0  # Horizontal

Camera Shake:

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- name: "shake"
  operation: "motion_blur"
  params:
    kernel_size: 3
    angle: 45

Vertical Panning:

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- name: "pan"
  operation: "motion_blur"
  params:
    kernel_size: 15
    angle: 90

Using the Repeat Parameter

All operations support the repeat parameter (1-100) to apply the same operation multiple times sequentially:

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- name: "repeated_compression"
  operation: "compression"
  repeat: 5                 # Apply 5 times
  params:
    quality: 50
    subsampling: 2

Repeat vs. Multi-Compress

  • repeat with compression: Each iteration uses the same parameters (quality 50 five times)
  • multi_compress: Supports quality decay curves (quality decreases across iterations)

When to use each:

  • Use repeat for cumulative degradation with fixed settings
  • Use multi_compress for progressive quality reduction

Repeat Examples

Repeated Downscaling:

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- name: "cascade_downscale"
  operation: "downscale"
  repeat: 3
  params:
    scale: 0.8  # Each iteration: 80% of previous size
    upscale: false

Multiple Blur Passes:

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- name: "blur_stack"
  operation: "motion_blur"
  repeat: 3
  params:
    kernel_size: 2
    angle: 0

Combining Operations

Create complex degradation patterns by chaining operations:

Social Media Compression 

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pipeline:
  steps:
    - name: "downscale"
      operation: "downscale"
      params:
        scale: 0.8

    - name: "multi_gen"
      operation: "multi_compress"
      params:
        iterations: 4
        quality_start: 75
        quality_end: 45
        decay: "linear"

Glitch Art 

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pipeline:
  steps:
    - name: "extreme_pixelation"
      operation: "downscale"
      params:
        scale: 0.08
        upscale: true
        upscale_method: "nearest"

    - name: "severe_compression"
      operation: "compression"
      params:
        quality: 5
        subsampling: 2

    - name: "multi_gen_glitch"
      operation: "multi_compress"
      params:
        iterations: 12
        quality_start: 30
        quality_end: 5
        decay: "exponential"

VHS/Analog Degradation 

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pipeline:
  steps:
    - name: "scanlines"
      operation: "motion_blur"
      params:
        kernel_size: 7
        angle: 0

    - name: "analog_compression"
      operation: "compression"
      params:
        quality: 35
        subsampling: 2

    - name: "resolution_loss"
      operation: "downscale"
      params:
        scale: 0.5
        upscale: true
        upscale_method: "bilinear"

Best Practices

  1. Start subtle: Begin with moderate parameters and increase intensity
  2. Preserve intermediates: Check intermediate outputs to understand each step
  3. Experiment with order: Operation order significantly affects results
  4. Use repeat wisely: For progressive decay, prefer multi_compress over repeat

Next Steps

For detailed parameter ranges and visual examples, see the complete Filter Guide.

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Algorithmic transformation exploring digital media through the artistic voices of Rimbaud and Dominique de Groen.