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ASS Validator

ASS Input

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Validation Results

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About ASS Validator

Our ASS Validator is a powerful, free online tool that ensures your ASS (Advanced SubStation Alpha) files meet proper format standards and structural requirements. ASS is the most advanced subtitle format, offering extensive styling, positioning, and animation capabilities. Our validator checks syntax, section structure, style definitions, and provides detailed feedback to help you create perfect advanced subtitle files.

What is ASS Format?

ASS (Advanced SubStation Alpha) is a sophisticated subtitle format that extends the original SubStation Alpha format with advanced features. Developed for complex subtitle styling, ASS supports multiple fonts, colors, positioning, animations, and special effects. It's widely used for anime subtitles, karaoke, and professional video production where advanced visual presentation is required.

ASS Format Structure

Required ASS Sections:

[Script Info]
Title: Your Title Here
ScriptType: v4.00+

[V4+ Styles]
Format: Name, Fontname, Fontsize, ...
Style: Default,Arial,20,&H00FFFFFF,...

[Events]
Format: Layer, Start, End, Style, Name, ...
Dialogue: 0,0:00:00.00,0:00:03.50,Default,,0,0,0,,Text here

ASS Validation Features

  • Section Structure: Validates required [Script Info], [V4+ Styles], and [Events] sections
  • Format Lines: Checks proper Format line definitions in styles and events
  • Style Validation: Verifies style definitions and parameter counts
  • Dialogue Format: Validates dialogue line structure and field counts
  • Timestamp Format: Checks H:MM:SS.CC time format compliance
  • Color Codes: Validates hexadecimal color format (&HAABBGGRR)

ASS Advanced Features

Style Properties: Font, size, colors, outline, shadow, alignment, margins.

Override Tags: Runtime style changes with {\ tag syntax.

Positioning: Absolute and relative positioning with {\ pos and move tags.

Animations: Complex animations with {\ t transformation tags.

Drawing: Vector graphics with {\ p drawing mode.

Karaoke: Syllable-level timing with {\ k and kf tags.

ASS Section Details

[Script Info]

  • • Title: Subtitle title
  • • ScriptType: Usually v4.00+
  • • PlayResX/Y: Video resolution
  • • Timer: Timing precision
  • • Collisions: Overlap handling

[V4+ Styles]

  • • Format: Field definitions
  • • Style: Style definitions
  • • Font properties
  • • Color specifications
  • • Positioning settings

[Events]

  • • Format: Event field order
  • • Dialogue: Subtitle lines
  • • Comment: Non-displayed text
  • • Picture/Sound: Media events
  • • Movie: Video overlay

Common ASS Validation Issues

Missing Sections: Required sections not present or improperly named.

Format Mismatch: Style or dialogue fields don't match format definition.

Invalid Colors: Incorrect hexadecimal color format or missing &H prefix.

Time Format: Incorrect timestamp format or invalid time values.

Field Count: Wrong number of fields in style or dialogue lines.

Tag Syntax: Malformed override tags or drawing commands.

ASS Color System

Color Format: &HAABBGGRR

  • • &H prefix indicates hexadecimal color
  • • AA: Alpha (transparency) - 00=opaque, FF=transparent
  • • BB: Blue component (00-FF)
  • • GG: Green component (00-FF)
  • • RR: Red component (00-FF)
  • • Example: &H00FFFFFF = opaque white

Why Use ASS Format?

ASS format provides unmatched flexibility for subtitle presentation. It's essential for projects requiring sophisticated visual styling, positioning control, or animation effects. Common use cases include anime subtitles with complex typesetting, karaoke with syllable highlighting, educational content with emphasis effects, and professional productions requiring pixel-perfect subtitle placement.

Supported Applications

Video Players: VLC Media Player, MPC-HC, PotPlayer, mpv, Kodi

Subtitle Editors: Aegisub, Subtitle Edit, VisualSubSync, Jubler

Encoding Tools: MKVToolNix, FFmpeg, Handbrake, MeGUI

Streaming: Jellyfin, Plex, Emby with advanced subtitle support

Mobile Apps: MX Player, VLC Mobile, BSPlayer, KMPlayer

Best Practices for ASS Files

  • Always include all three required sections in proper order
  • Define format lines before any style or dialogue entries
  • Use consistent style names throughout the file
  • Test complex animations and effects before finalizing
  • Keep drawing commands simple for better compatibility
  • Document custom styles and effects with comments
  • Validate color codes and ensure proper alpha values
  • Consider playback device limitations when using advanced features