Ffmpeg Karaoke Animated Text

CRITICAL GUIDELINES

Windows File Path Requirements

MANDATORY: Always Use Backslashes on Windows for File Paths

When using Edit or Write tools on Windows, you MUST use backslashes (\) in file paths, NOT forward slashes (/).

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FFmpeg Karaoke & Animated Text

Use this skill for karaoke subtitles, kinetic typography, scrolling credits, animated lower thirds, typewriter text, timers, and dynamic text overlays. Keep answers practical: identify whether ASS or drawtext is the right tool, provide a copy-paste-ready command or ASS snippet, and call out timing units.

Quick Reference

When to Use This Skill

Use for animated text and karaoke:

• Music video lyrics with karaoke highlighting
• Movie-style scrolling credits
• Animated titles and lower thirds
• Typewriter text reveal
• Kinetic typography and word pops
• Countdown timers, stopwatches, frame counters, timecode overlays
• Multi-line text and textfile-driven overlays

Tool Choice: ASS vs drawtext

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CRITICAL: ASS Time Unit Reference

ASS uses TWO DIFFERENT time unit systems. This is a common source of bugs. Karaoke tags use centiseconds; ASS animation tags use milliseconds; FFmpeg drawtext expressions use seconds.

Karaoke Tags = CENTISECONDS (1/100 second)

Conversion: seconds * 100 = centiseconds.

Animation Tags = MILLISECONDS (1/1000 second)

Conversion: seconds * 1000 = milliseconds.

FFmpeg drawtext = SECONDS

Common Mistake

; WRONG - mixing units:
Dialogue: 0,0:00:00.00,0:00:02.00,Style,,0,0,0,,{\k100\t(0,100,...)}Word
; {\k100} = 1 second, but \t(0,100,...) = 0.1 seconds

; CORRECT - matched duration:
Dialogue: 0,0:00:00.00,0:00:02.00,Style,,0,0,0,,{\k100\t(0,1000,...)}Word

For the full timing-unit reference, use ffmpeg-animation-timing-reference.

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Karaoke Core Pattern

[Script Info]
ScriptType: v4.00+
PlayResX: 1920
PlayResY: 1080

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Karaoke,Arial,72,&H00FFFFFF,&H000000FF,&H00000000,&H80000000,1,0,0,0,100,100,0,0,1,3,2,2,10,10,50,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:00:05.00,Karaoke,,0,0,0,,{\k50}Twinkle {\k50}twinkle {\k50}little {\k50}star

Burn into video:

ffmpeg -i input.mp4 \
  -vf "ass=karaoke.ass" \
  -c:v libx264 -crf 18 -c:a copy \
  output_karaoke.mp4

For advanced styles, neon/gradient karaoke, per-character timing, and animated karaoke transforms, see references/karaoke-ass-patterns.md.

drawtext Core Patterns

# Fade in title over 2 seconds
ffmpeg -i input.mp4 \
  -vf "drawtext=text='Title':fontsize=100:fontcolor=white:x=(w-tw)/2:y=(h-th)/2:alpha='min(1,t/2)'" \
  output.mp4

# Vertical bounce
ffmpeg -i input.mp4 \
  -vf "drawtext=text='BOUNCE':fontsize=80:fontcolor=yellow:x=(w-tw)/2:y='(h-th)/2+50*sin(t*5)'" \
  bounce.mp4

# Scroll credits upward at 80px/sec
ffmpeg -i input.mp4 \
  -vf "drawtext=textfile=credits.txt:fontsize=48:fontcolor=white:x=(w-tw)/2:y=h-80*t" \
  -c:v libx264 -crf 18 output.mp4

For spring/elastic/wobble formulas, typewriter effects, lower thirds, countdowns, stopwatches, metadata overlays, and multi-line text, see references/drawtext-animation-recipes.md.

Workflow

1. Choose ASS or drawtext using the tool-choice table. 2. Verify timing units before writing tags or expressions. 3. Probe input when needed (ffprobe) to confirm duration, frame rate, and resolution. 4. Set output encoding explicitly when burning text (-c:v libx264 -crf 18, audio copy only when compatible). 5. Use short test renders (-ss, -t) before rendering a full music video or credit roll. 6. Check readability: karaoke should track words within ~30ms; captions need enough display time; scrolling credits should move slowly enough to read.

Reference Map

• references/karaoke-ass-patterns.md - ASS karaoke basics, \k / \kf / \ko, BPM timing, tag selection, neon/gradient styles, per-character karaoke, ASS color format, animated karaoke effects.
• references/drawtext-animation-recipes.md - Spring bounce, elastic overshoot, easing approximations, wobble/wiggle, pulse, wipes, typewriter, fades, moving text, kinetic typography, lower thirds, countdowns, stopwatches, dynamic variables, multi-line text.
• references/scrolling-credits-and-expressions.md - Music/education/credits timing, vertical credits, horizontal tickers, ASS rotation workaround, drawtext variables and expression cookbook.

Related Skills

• ffmpeg-animation-timing-reference - Timing units, caption durations, easing, sync tolerances
• ffmpeg-captions-subtitles - Subtitle fundamentals, extraction, burn-in, styling
• ffmpeg-kinetic-captions - Word-level pop/bounce/grow caption effects
• viral-video-animated-captions - Social-video caption templates
• ffmpeg-shapes-graphics - Boxes, backgrounds, graphic overlays
• ffmpeg-transitions-effects - xfade and video transitions

Drawtext Animation Recipes

Advanced FFmpeg drawtext formulas and complete commands for animated text, kinetic typography, timers, and dynamic overlays.

Spring Physics Implementation

Create natural bounce effects with exponential decay:

# Vertical spring bounce (decaying oscillation)
# Formula: y_offset = amplitude * e^(-decay*t) * sin(frequency*t)
-vf "drawtext=text='BOUNCE':fontsize=80:fontcolor=white:\
     x=(w-tw)/2:\
     y='(h-th)/2-30*exp(-t*2.5)*sin(t*15)'"

# Breakdown:
# -30*exp(-t*2.5) = amplitude decays from 30px to 0
# sin(t*15) = oscillates at 15 rad/s (≈2.4 Hz)
# Combines: bounces 2-3 times over ~1 second, settling at center

Parameter tuning:

• Decay rate (2.5): Higher = faster settling (3-4 for quick, 1-2 for slow)
• Frequency (15): Higher = more bounces (10-12 slow, 15-20 fast)
• Amplitude (30): Bounce height in pixels

Elastic Overshoot Effect

# Elastic scale effect (rubber band)
# Overshoots target size multiple times before settling
-vf "drawtext=text='ELASTIC':fontsize='72*(1+0.4*exp(-t*3)*sin(t*20))':\
     fontcolor=yellow:x=(w-tw)/2:y=(h-th)/2"

# Scale oscillates: 72px → 101px → 65px → 80px → 70px → 72px (settled)
# Mathematical basis: e^(-3t) * sin(20t) creates damped oscillation

Elastic parameters:

• Base fontsize: 72 (target)
• Overshoot: 0.4 (40% maximum deviation) → 72 * 1.4 = 101px peak
• Decay: 3 (settles in ~1.5 seconds)
• Frequency: 20 (multiple small bounces)

Bezier Curve Approximation (Ease-In-Out)

FFmpeg doesn't support bezier directly, but we can approximate with piecewise functions:

# Ease-out approximation (fast start, slow end)
# Cubic bezier (0, 0, 0.2, 1) approximation
-vf "drawtext=text='EASE OUT':\
     alpha='if(lt(t,0.5),1-exp(-t*6),1)':\
     fontsize=80:fontcolor=white:x=(w-tw)/2:y=(h-th)/2:\
     enable='lt(t,1)'"

# Ease-in approximation (slow start, fast end)
# Cubic bezier (0.8, 0, 1, 1) approximation
-vf "drawtext=text='EASE IN':\
     alpha='if(lt(t,0.5),exp(-(1-t)*6),0)':\
     fontsize=80:fontcolor=white:x=(w-tw)/2:y=(h-th)/2:\
     enable='between(t,1,2)'"

# Ease-in-out (S-curve) using sigmoid approximation
-vf "drawtext=text='SMOOTH':\
     alpha='1/(1+exp(-10*(t-0.5)))':\
     fontsize=80:fontcolor=white:x=(w-tw)/2:y=(h-th)/2:\
     enable='lt(t,1)'"

Mathematical reasoning:

• Exponential ease: 1 - e^(-kt) creates natural deceleration
• Sigmoid curve: 1/(1+e^(-k(t-0.5))) creates smooth S-curve (ease-in-out)
• k parameter: Controls transition sharpness (6-10 for subtle, 15-20 for pronounced)

Wobble/Wiggle Effects

Create organic, unpredictable motion:

# Dual-frequency wobble (complex motion)
# Combines two sine waves at different frequencies for organic feel
-vf "drawtext=text='WOBBLE':fontsize=80:fontcolor=white:\
     x='(w-tw)/2+8*sin(t*7)+4*sin(t*17)':\
     y='(h-th)/2+6*cos(t*7)+3*cos(t*13)'"

# Breakdown:
# Primary wobble: 8*sin(t*7) = 8px amplitude, 7 rad/s (1.1 Hz)
# Secondary wobble: 4*sin(t*17) = 4px amplitude, 17 rad/s (2.7 Hz)
# Result: Complex, organic motion pattern

# Drunk/unstable effect (low frequency, large amplitude)
-vf "drawtext=text='UNSTABLE':fontsize=80:fontcolor=white:\
     x='(w-tw)/2+20*sin(t*2.5)+10*sin(t*6.3)':\
     y='(h-th)/2+15*cos(t*3.1)+8*cos(t*7.2)'"

Wobble design principles:

• Use two frequencies (primary + secondary) for natural randomness
• Prime number ratios (e.g., 7 and 17) prevent pattern repetition
• Amplitude ratio 2:1 (primary twice the secondary) for balanced motion

Pulse with Variable Intensity

Create heartbeat or alarm-style pulsing:

# Heartbeat pulse (two quick beats, pause)
# Pattern: THUMP-thump ... pause ... THUMP-thump
-vf "drawtext=text='♥ HEARTBEAT ♥':\
     fontsize='80+25*max(0,sin(t*15)*exp(-mod(t,1.2)*10))':\
     fontcolor=red:x=(w-tw)/2:y=(h-th)/2"

# Breakdown:
# sin(t*15) = rapid oscillation
# exp(-mod(t,1.2)*10) = decay envelope every 1.2 seconds
# max(0, ...) = only positive pulses
# Result: Pulse decays quickly, resets every 1.2s

# Alarm pulse (constant urgent rhythm)
-vf "drawtext=text='ALERT':\
     fontsize='80+20*abs(sin(t*8))':\
     fontcolor=yellow:x=(w-tw)/2:y=(h-th)/2"

# abs(sin(t*8)) creates continuous pulsing at 8 rad/s (1.3 Hz)

Text Reveal Animations (Wipe Effects)

Horizontal Wipe (Left to Right)

# Clip text progressively from left
# Uses drawbox mask to reveal text over time
-filter_complex "\
  [0:v]drawtext=text='REVEALED':fontsize=100:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2[txt];\
  [txt]drawbox=x=0:y=0:w='min(w,t*500)':h=h:c=black@0:t=fill:replace=1[v]" \
  -map "[v]"

# Breakdown:
# w='min(w,t*500)' = width grows at 500 pixels/second
# Creates left-to-right reveal effect

Vertical Wipe (Bottom to Top)

# Text rises from bottom
-vf "drawtext=text='RISING':fontsize=100:fontcolor=white:\
     x=(w-tw)/2:\
     y='if(lt(t,1),h-t*h,0)'"

# y position: starts at h (bottom), moves to 0 (top) over 1 second

Countdown Timer Variations

Animated Countdown with Anticipation

# Countdown that pulses on each second change
-vf "drawtext=text='%{eif\:10-floor(t)\:d}':\
     fontsize='200+50*abs(sin(floor(t)*50))*exp(-(t-floor(t))*8)':\
     fontcolor=white:x=(w-tw)/2:y=(h-th)/2"

# Breakdown:
# %{eif\:10-floor(t)\:d} = countdown number (10, 9, 8, ...)
# abs(sin(floor(t)*50)) = trigger pulse on integer seconds
# exp(-(t-floor(t))*8) = decay within each second
# Result: Number "pops" at each second change

Split-Flap Display (Mechanical)

# Simulates old-school flip counter with vertical offset
-vf "drawtext=text='%{eif\:10-floor(t)\:d}':\
     fontsize=200:fontcolor=white:\
     x=(w-tw)/2:\
     y='(h-th)/2-(t-floor(t))*100*step(t-floor(t))'"

# y offset creates "flipping" motion at second boundaries

Typewriter Effect

Character-by-Character Reveal

# Typewriter effect using enable
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=10" \
  -vf "\
    drawtext=text='H':x=100:y=500:fontsize=72:fontcolor=white:enable='gte(t,0.0)',\
    drawtext=text='e':x=150:y=500:fontsize=72:fontcolor=white:enable='gte(t,0.1)',\
    drawtext=text='l':x=200:y=500:fontsize=72:fontcolor=white:enable='gte(t,0.2)',\
    drawtext=text='l':x=250:y=500:fontsize=72:fontcolor=white:enable='gte(t,0.3)',\
    drawtext=text='o':x=300:y=500:fontsize=72:fontcolor=white:enable='gte(t,0.4)'" \
  typewriter.mp4

Typewriter with Cursor

# Blinking cursor during typing
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=5" \
  -vf "\
    drawtext=text='Hello':fontsize=72:fontcolor=white:x=100:y=500:\
             enable='gte(t,0)':alpha='min(1,(t-0)/0.5)',\
    drawtext=text='|':fontsize=72:fontcolor=white:\
             x='100+72*min(5,floor(t/0.1))':y=500:\
             alpha='lt(mod(t,0.5),0.25)'" \
  typewriter_cursor.mp4

Text Fade Effects

# Simple fade in
ffmpeg -i input.mp4 \
  -vf "drawtext=text='Title':fontsize=100:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2:\
       alpha='if(lt(t,2),t/2,1)'" \
  fade_in.mp4

# Fade out (assuming 10 second video)
ffmpeg -i input.mp4 \
  -vf "drawtext=text='Goodbye':fontsize=100:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2:\
       alpha='if(gt(t,8),1-(t-8)/2,1)'" \
  fade_out.mp4

# Title card with fade in/out
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=6" \
  -vf "drawtext=text='Chapter One':fontsize=120:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2:\
       alpha='if(lt(t,1),t,if(gt(t,5),1-(t-5),1))'" \
  title_card.mp4

Moving Text

# Vertical bounce
ffmpeg -i input.mp4 \
  -vf "drawtext=text='BOUNCE':fontsize=80:fontcolor=yellow:\
       x=(w-tw)/2:\
       y='(h-th)/2+50*sin(t*5)'" \
  bounce.mp4

# Horizontal bounce
ffmpeg -i input.mp4 \
  -vf "drawtext=text='PING PONG':fontsize=60:fontcolor=cyan:\
       x='(w-tw)/2+200*sin(t*3)':\
       y=(h-th)/2" \
  horizontal_bounce.mp4

# Text moving in circle
ffmpeg -i input.mp4 \
  -vf "drawtext=text='ORBIT':fontsize=60:fontcolor=white:\
       x='(w/2)+200*cos(t*2)-tw/2':\
       y='(h/2)+200*sin(t*2)-th/2'" \
  orbit.mp4

# Slide in from right
ffmpeg -i input.mp4 \
  -vf "drawtext=text='SLIDE IN':fontsize=80:fontcolor=white:\
       x='if(lt(t,1),w-tw*(t),w-tw)':\
       y=(h-th)/2" \
  slide_in.mp4

# Slide in from left
ffmpeg -i input.mp4 \
  -vf "drawtext=text='FROM LEFT':fontsize=80:fontcolor=white:\
       x='if(lt(t,1),-tw+tw*t,0)':\
       y=(h-th)/2" \
  slide_left.mp4

Kinetic Typography

# Words appearing with scale
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=8" \
  -vf "\
    drawtext=text='THIS':fontsize='72*(1+0.3*exp(-3*(t-1)))':fontcolor=white:\
             x=(w-tw)/2:y=h/2-100:enable='gte(t,1)',\
    drawtext=text='IS':fontsize='72*(1+0.3*exp(-3*(t-2)))':fontcolor=white:\
             x=(w-tw)/2:y=h/2:enable='gte(t,2)',\
    drawtext=text='KINETIC':fontsize='72*(1+0.3*exp(-3*(t-3)))':fontcolor=red:\
             x=(w-tw)/2:y=h/2+100:enable='gte(t,3)'" \
  kinetic_pop.mp4

# Shaking text (impact effect)
ffmpeg -i input.mp4 \
  -vf "drawtext=text='IMPACT':fontsize=120:fontcolor=white:\
       x='(w-tw)/2+10*sin(t*50)*exp(-t*2)':\
       y='(h-th)/2+10*cos(t*50)*exp(-t*2)'" \
  shake.mp4

Lower Thirds

# Name and title lower third
ffmpeg -i input.mp4 \
  -vf "\
    drawbox=x=50:y=h-150:w=500:h=100:c=blue@0.7:t=fill,\
    drawtext=text='Name':fontsize=36:fontcolor=white:\
             x=70:y=h-140,\
    drawtext=text='Title':fontsize=24:fontcolor=white@0.8:\
             x=70:y=h-100" \
  lower_third.mp4

# Slide-in lower third
ffmpeg -i input.mp4 \
  -vf "\
    drawbox=x='if(lt(t,0.5),-500+1000*t,50)':\
            y=h-150:w=500:h=100:c=blue@0.7:t=fill:\
            enable='between(t,0,8)',\
    drawtext=text='Name':fontsize=36:fontcolor=white:\
             x='if(lt(t,0.5),-430+1000*t,70)':y=h-140:\
             alpha='min(1,(t-0.3)/0.3)':\
             enable='between(t,0.3,8)',\
    drawtext=text='Title':fontsize=24:fontcolor=white:\
             x='if(lt(t,0.5),-430+1000*t,70)':y=h-100:\
             alpha='min(1,(t-0.5)/0.3)':\
             enable='between(t,0.5,8)'" \
  animated_lower_third.mp4

Countdown, Stopwatch, and Dynamic Text

# 10 second countdown
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=10" \
  -vf "drawtext=text='%{eif\:10-t\:d}':fontsize=200:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2" \
  countdown.mp4

# Pulsing countdown
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=10" \
  -vf "drawtext=text='%{eif\:10-t\:d}':\
       fontsize='200+30*sin(t*10)*exp(-mod(t,1)*3)':\
       fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2" \
  pulsing_countdown.mp4

# Count up timer (MM:SS)
ffmpeg -f lavfi -i "color=c=black:s=1920x1080:d=120" \
  -vf "drawtext=text='%{eif\:floor(t/60)\:d\:2}\:%{eif\:mod(t,60)\:d\:2}':\
       fontsize=100:fontcolor=green:\
       x=(w-tw)/2:y=(h-th)/2" \
  stopwatch.mp4

# Show frame number
ffmpeg -i input.mp4 \
  -vf "drawtext=text='Frame\: %{frame_num}':\
       fontsize=24:fontcolor=white:\
       x=10:y=10" \
  frame_numbers.mp4

# Show timecode
ffmpeg -i input.mp4 \
  -vf "drawtext=text='%{pts\:hms}':\
       fontsize=24:fontcolor=white:\
       x=10:y=10" \
  timecode.mp4

# With milliseconds
ffmpeg -i input.mp4 \
  -vf "drawtext=text='%{pts}':\
       fontsize=24:fontcolor=white:\
       x=10:y=10" \
  timecode_ms.mp4

# Show title metadata
ffmpeg -i input.mp4 \
  -vf "drawtext=text='%{metadata\:title}':\
       fontsize=24:fontcolor=white:\
       x=10:y=h-40" \
  metadata.mp4

Multi-Line Text

# Multi-line centered text
ffmpeg -i input.mp4 \
  -vf "drawtext=text='Line One
Line Two
Line Three':\
       fontsize=48:fontcolor=white:\
       x=(w-tw)/2:y=(h-th)/2:\
       line_spacing=20" \
  multiline.mp4

# Use text file for long text
ffmpeg -i input.mp4 \
  -vf "drawtext=textfile=message.txt:\
       fontsize=36:fontcolor=white:\
       x=50:y=50:\
       line_spacing=10" \
  from_file.mp4

Karaoke ASS Patterns

Detailed ASS/SSA karaoke subtitle recipes, timing tags, styling patterns, and burn-in commands.

ASS Karaoke Basics

ASS (Advanced SubStation Alpha) supports karaoke timing with \k tags.

[Script Info]
Title: Karaoke Example
ScriptType: v4.00+
PlayResX: 1920
PlayResY: 1080

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Karaoke,Arial,72,&H00FFFFFF,&H000000FF,&H00000000,&H80000000,1,0,0,0,100,100,0,0,1,3,2,2,10,10,50,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:00:05.00,Karaoke,,0,0,0,,{\k50}Twinkle {\k50}twinkle {\k50}little {\k50}star
Dialogue: 0,0:00:05.00,0:00:09.00,Karaoke,,0,0,0,,{\k50}How {\k50}I {\k50}wonder {\k50}what {\k50}you {\k50}are

Karaoke Timing Tags

Duration is in centiseconds (100 = 1 second).

Advanced Karaoke Timing Parameters

Optimal Karaoke Timing by Song Tempo

Karaoke Tag Selection Guide

\k (Instant Fill) - Best For

• Very short syllables: <120 centiseconds (1.2s)
• Rap/hip-hop: Fast lyric delivery
• Staccato rhythm: Percussive, sharp delivery

; Rap example (fast succession):
{\k25}Yo {\k20}this {\k15}is {\k30}rapid {\k25}fire {\k35}flow

\kf (Progressive Fill) - Best For

• Long syllables: >120 centiseconds (1.2s)
• Ballads: Drawn-out emotional delivery
• Smooth transitions: Clean visual sweep

; Ballad example (sustained notes):
{\kf150}Loooooove {\kf120}yoooou {\kf180}foreeeever

Recommended: Use \kf for any syllable >100 centiseconds for smoothest visual effect.

\ko (Outline Reveal) - Best For

• High contrast: Text that needs to "pop"
• Neon/glow styles: Outline-heavy fonts
• Special emphasis: Chorus, key phrases

; Neon karaoke style:
[V4+ Styles]
Style: NeonKaraoke,Arial,80,&H00000000,&H0000FF00,&H0000FF00,&H00000000,1,0,0,0,100,100,0,0,3,6,0,2,10,10,50,1

[Events]
Dialogue: 0,0:00:01.00,0:00:05.00,NeonKaraoke,,0,0,0,,{\ko50}Electric {\ko60}neon {\ko40}glow

Multi-Color Karaoke Transitions

Create dynamic color changes during karaoke fill:

; Gradient karaoke: Yellow → Orange → Red
[V4+ Styles]
Style: GradientKaraoke,Impact,80,&H0000FFFF,&H000000FF,&H00000000,&H00000000,1,0,0,0,100,100,0,0,1,5,0,2,10,10,50,1
;                                   Primary^      Secondary^
;                                   Yellow(start) Red(filled)

; Add intermediate color transition with \t tags:
[Events]
Dialogue: 0,0:00:01.00,0:00:05.00,GradientKaraoke,,0,0,0,,{\kf80\t(0,400,\2c&H0000A5FF&)}Word1 {\kf100\t(0,500,\2c&H0000A5FF&)}Word2
;                                                                   ↑ Orange midpoint

Color progression formula:

Start: &H0000FFFF (Yellow)
Mid:   &H0000A5FF (Orange) - 50% through karaoke fill
End:   &H000000FF (Red)

Per-Character Karaoke

For very precise timing (character-by-character):

; Each character gets individual timing (manual, tedious)
{\k10}H{\k8}e{\k12}l{\k10}l{\k15}o {\k20}w{\k18}o{\k15}r{\k12}l{\k10}d

; Best practice: Use tools like Aegisub Karaoke Timer
; Manual character timing only for special effects

Use character-level karaoke for:

• Slow-motion word reveal
• Dramatic emphasis
• Non-linear character highlighting (e.g., every other letter)

Apply Karaoke ASS to Video

# Burn karaoke subtitles into video
ffmpeg -i input.mp4 \
  -vf "ass=karaoke.ass" \
  -c:v libx264 -crf 18 -c:a copy \
  output_karaoke.mp4

# With specific fonts directory
ffmpeg -i input.mp4 \
  -vf "ass=karaoke.ass:fontsdir=/path/to/fonts" \
  output.mp4

Advanced ASS Karaoke Styles

[V4+ Styles]
; Gradient karaoke (yellow to red)
Style: KaraokeGradient,Impact,80,&H0000FFFF,&H000000FF,&H00000000,&H80000000,1,0,0,0,100,100,0,0,1,4,2,2,10,10,60,1

; Glow effect karaoke
Style: KaraokeGlow,Arial Black,72,&H00FFFFFF,&H00FF00FF,&H00FF00FF,&H00000000,1,0,0,0,100,100,0,0,4,0,20,2,10,10,50,1

; Outline only (neon style)
Style: KaraokeNeon,Arial,80,&H00000000,&H0000FF00,&H0000FF00,&H00000000,1,0,0,0,100,100,0,0,3,4,0,2,10,10,50,1

[Events]
; Word-by-word with effects
Dialogue: 0,0:00:01.00,0:00:05.00,KaraokeGradient,,0,0,0,,{\k50\fad(200,0)}Never {\k50}gonna {\k50}give {\k50}you {\k50}up
; With positioning
Dialogue: 0,0:00:05.00,0:00:09.00,KaraokeGlow,,0,0,0,,{\pos(960,900)\k50}Never {\k50}gonna {\k50}let {\k50}you {\k50}down

ASS Color Format

ASS uses &HAABBGGRR format (Alpha, Blue, Green, Red):

• &H00FFFFFF = White (fully opaque)
• &H000000FF = Red
• &H0000FF00 = Green
• &H00FF0000 = Blue
• &H80000000 = 50% transparent black

Karaoke with Animation Effects

[Events]
; Bounce effect per word
Dialogue: 0,0:00:01.00,0:00:05.00,Karaoke,,0,0,0,,{\k50\t(0,500,\fry360)}Word1 {\k50\t(0,500,\fry360)}Word2

; Scale pop on highlight
Dialogue: 0,0:00:01.00,0:00:05.00,Karaoke,,0,0,0,,{\k50\t(0,100,\fscx120\fscy120)\t(100,200,\fscx100\fscy100)}Pop

; Color transition
Dialogue: 0,0:00:01.00,0:00:05.00,Karaoke,,0,0,0,,{\k100\t(0,1000,\c&H0000FF&)}Red {\k100\t(0,1000,\c&H00FF00&)}Green

ASS Animation Tags Reference

Scrolling Credits and Drawtext Expressions

Recipes for vertical credits, horizontal tickers, genre/content timing, and drawtext expression reference.

Optimal Animation Timing by Content Type

Music Video Karaoke

Educational Content

# Slow, clear typewriter for learning
# 80ms per character = comfortable reading pace
-vf "drawtext=textfile=lesson.txt:\
     fontsize=48:fontcolor=white:\
     x=50:y=100:\
     enable='gte(n,eif(n/24,80))'"
# Each character appears every 80/24 ≈ 3.3 frames at 24fps

Scrolling Credits Optimization

# Professional credits scroll
# Speed: 60-80 pixels/second for comfortable reading
-vf "drawtext=textfile=credits.txt:\
     fontsize=42:fontcolor=white:\
     x=(w-tw)/2:\
     y='h-60*t':\
     line_spacing=25"

# Calculation:
# 60 px/s at 42px font = ~1.4 lines/second
# For 50 lines: 50/1.4 = ~36 seconds total duration

Credits readability formula:

scroll_speed = font_size * 1.2 to 1.5  (pixels/second)
total_duration = (line_count * line_height) / scroll_speed

Example:
font_size = 42px
line_height = 42 + 25 (spacing) = 67px
scroll_speed = 42 * 1.4 = 59 px/s
50 lines = 50 * 67 = 3350 pixels
duration = 3350 / 59 = 56.8 seconds

Scrolling Credits

Vertical Scroll (Bottom to Top)

# Basic scrolling credits
ffmpeg -i input.mp4 \
  -vf "drawtext=textfile=credits.txt:\
       fontfile=/path/to/font.ttf:\
       fontsize=48:\
       fontcolor=white:\
       x=(w-tw)/2:\
       y=h-80*t" \
  -c:v libx264 -crf 18 output.mp4

# y=h-80*t: Start at bottom (h), move up at 80 pixels/second

credits.txt Format

DIRECTED BY
Name

PRODUCED BY
Name

STARRING
Actor One
Actor Two
Actor Three

MUSIC BY
Composer Name

SPECIAL THANKS
Everyone

Scrolling Credits with Sections

# Multi-speed credits (slower for names)
ffmpeg -i input.mp4 \
  -vf "drawtext=textfile=credits.txt:\
       fontsize=48:\
       fontcolor=white:\
       x=(w-tw)/2:\
       y='h-60*t':\
       line_spacing=20" \
  output.mp4

Horizontal Scrolling (News Ticker)

# Right to left scroll
ffmpeg -i input.mp4 \
  -vf "drawtext=text='BREAKING NEWS... This is a scrolling ticker message':\
       fontsize=36:\
       fontcolor=white:\
       y=h-50:\
       x='w-mod(t*150,w+tw)'" \
  ticker.mp4

# x='w-mod(t*150,w+tw)': Continuous scroll at 150 pixels/second

Looping Horizontal Scroll

# Seamless looping ticker
ffmpeg -i input.mp4 \
  -vf "drawtext=text='   LIVE NEWS     BREAKING STORY     UPDATES   ':\
       fontsize=40:\
       fontcolor=yellow:\
       y=h-60:\
       x='w-mod(t*200\,w+tw)':\
       box=1:boxcolor=red@0.8:boxborderw=10" \
  news_ticker.mp4

Rotation Animation via ASS

drawtext doesn't support rotation natively. Use ASS subtitles for rotation:

# Create spinning.ass
cat << 'EOF' > spinning.ass
[Script Info]
ScriptType: v4.00+
PlayResX: 1920
PlayResY: 1080

[V4+ Styles]
Style: Spin,Arial,72,&H00FFFFFF,&H00FFFFFF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,2,0,5,0,0,0,1

[Events]
Dialogue: 0,0:00:00.00,0:00:05.00,Spin,,0,0,0,,{\an5\pos(960,540)\t(0,5000,\frz1080)}SPINNING
EOF

ffmpeg -i input.mp4 -vf "ass=spinning.ass" output.mp4

Expression Reference

Useful Time Expressions

Useful Variables

Common Patterns

# Appear after 2 seconds
enable='gte(t,2)'

# Visible between 2-5 seconds
enable='between(t,2,5)'

# Fade in over 1 second
alpha='min(1,t)'

# Center horizontally
x='(w-tw)/2'

# Center vertically
y='(h-th)/2'

# Loop position
x='mod(t*100,w)'

# Smooth oscillation
y='h/2+50*sin(t*3)'

# Decay animation
fontsize='100+50*exp(-t*2)'

Sources

Enhanced with research from:

• FFmpeg Drawtext Animation Exploration
• ASS Karaoke Tags Documentation
• Advanced Aegisub Karaoke
• Spring Physics for Animations
• Easing Functions Mathematical Reference
• FFmpeg Expression Evaluation