> ## Documentation Index
> Fetch the complete documentation index at: https://docs.videobgremover.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Video Timing & Duration Control | Remove Video Background
> Master video timing control with start times, durations, and source trimming. Learn composition duration rules, layer sequencing, and dynamic videos.
## Timeline Control
Control exactly when your video layers appear and disappear in your composition. The timing system has two levels:
**Which part** of the source video to use (trimming)
**When to show** the layer in the final video
## Composition Timeline
Control when layers appear in your final video:
### Start Time
Set when a layer begins appearing:
```typescript Node.js theme={"dark"}
// Layer appears at 2 seconds
comp.add(transparent).start(2.0)
// Layer appears immediately (default)
comp.add(transparent).start(0.0)
```
```python Python theme={"dark"}
# Layer appears at 2 seconds
comp.add(transparent).start(2.0)
# Layer appears immediately (default)
comp.add(transparent).start(0.0)
```
### Duration Control
Control how long layers are visible:
```typescript Node.js theme={"dark"}
// Show for exactly 5 seconds
comp.add(transparent).start(2.0).duration(5.0)
// Appears at 2s, disappears at 7s
// Show from 10s to 15s
comp.add(transparent).start(10.0).end(15.0)
// Appears at 10s, disappears at 15s
// Show from start time until end of composition
comp.add(transparent).start(5.0)
// Appears at 5s, continues until composition ends
```
```python Python theme={"dark"}
# Show for exactly 5 seconds
comp.add(transparent).start(2.0).duration(5.0)
# Appears at 2s, disappears at 7s
# Show from 10s to 15s
comp.add(transparent).start(10.0).end(15.0)
# Appears at 10s, disappears at 15s
# Show from start time until end of composition
comp.add(transparent).start(5.0)
# Appears at 5s, continues until composition ends
```
## Source Trimming
Use only specific parts of your source videos:
```typescript Node.js theme={"dark"}
// Use seconds 5-10 of the source video
const trimmed = transparent.subclip(5, 10)
comp.add(trimmed)
// Use from 3 seconds to end of source
const fromMiddle = transparent.subclip(3)
comp.add(fromMiddle)
// Or trim directly in composition
comp.add(transparent).subclip(2, 8)
```
```python Python theme={"dark"}
# Use seconds 5-10 of the source video
trimmed = transparent.subclip(5, 10)
comp.add(trimmed)
# Use from 3 seconds to end of source
from_middle = transparent.subclip(3)
comp.add(from_middle)
# Or trim directly in composition
comp.add(transparent).subclip(2, 8)
```
## Combined Timing
You can combine source trimming with composition timing:
```typescript Node.js theme={"dark"}
// Use seconds 1-4 of source (3 seconds of content)
// Show it at 10-13 seconds in the final video
comp.add(transparent)
.subclip(1, 4) // Source: use 1-4s (3s of content)
.start(10) // Composition: show at 10s
.duration(3) // Composition: show for 3s (10-13s)
```
```python Python theme={"dark"}
# Use seconds 1-4 of source (3 seconds of content)
# Show it at 10-13 seconds in the final video
comp.add(transparent) \
.subclip(1, 4) \ # Source: use 1-4s (3s of content)
.start(10) \ # Composition: show at 10s
.duration(3) # Composition: show for 3s (10-13s)
```
## Staggered Animations
Create dynamic sequences with layers appearing at different times:
```typescript Node.js theme={"dark"}
const videos = [transparent1, transparent2, transparent3, transparent4]
const positions = [
Anchor.TOP_LEFT, Anchor.TOP_RIGHT,
Anchor.BOTTOM_LEFT, Anchor.BOTTOM_RIGHT
]
videos.forEach((vid, i) => {
comp.add(vid)
.at(positions[i], 50, 50)
.size(SizeMode.CANVAS_PERCENT, { percent: 40 })
.start(i * 2) // Start every 2 seconds: 0s, 2s, 4s, 6s
.duration(6) // Each visible for 6 seconds
.opacity(0.8)
})
```
```python Python theme={"dark"}
videos = [transparent1, transparent2, transparent3, transparent4]
positions = [
Anchor.TOP_LEFT, Anchor.TOP_RIGHT,
Anchor.BOTTOM_LEFT, Anchor.BOTTOM_RIGHT
]
for i, (vid, pos) in enumerate(zip(videos, positions)):
comp.add(vid) \
.at(pos, dx=50, dy=50) \
.size(SizeMode.CANVAS_PERCENT, percent=40) \
.start(i * 2) \ # Start every 2 seconds: 0s, 2s, 4s, 6s
.duration(6) \ # Each visible for 6 seconds
.opacity(0.8)
```
## Audio Timing
Control audio from your layers:
```typescript Node.js theme={"dark"}
// Layer with full audio
comp.add(transparent1)
.start(0)
.audio(true, 1.0) // Full volume
// Layer with reduced audio
comp.add(transparent2)
.start(5)
.audio(true, 0.3) // 30% volume
// Silent layer
comp.add(transparent3)
.start(10)
.audio(false) // No audio
```
```python Python theme={"dark"}
# Layer with full audio
comp.add(transparent1) \
.start(0) \
.audio(enabled=True, volume=1.0) # Full volume
# Layer with reduced audio
comp.add(transparent2) \
.start(5) \
.audio(enabled=True, volume=0.3) # 30% volume
# Silent layer
comp.add(transparent3) \
.start(10) \
.audio(enabled=False) # No audio
```
## Duration Rules
Understanding how composition duration is determined:
### Rule 1: Video Background Controls Duration
When you use a video background, it determines the final length:
```typescript Node.js theme={"dark"}
// 30-second background video = 30-second final composition
const bg = Background.fromVideo('30_second_bg.mp4')
const comp = new Composition(bg)
comp.add(transparent) // Even if foreground is 5 seconds
// Final video will be 30 seconds
```
```python Python theme={"dark"}
# 30-second background video = 30-second final composition
bg = Background.from_video('30_second_bg.mp4')
comp = Composition(bg)
comp.add(transparent) # Even if foreground is 5 seconds
# Final video will be 30 seconds
```
### Rule 2: Color/Image Backgrounds Use Longest Foreground
Color and image backgrounds adapt to your content:
```typescript Node.js theme={"dark"}
// Color background adapts to content
const bg = Background.fromColor('#FF0000', 1920, 1080, 30)
const comp = new Composition(bg)
comp.add(tenSecondTransparent) // 10-second transparent video
comp.add(fiveSecondTransparent) // 5-second transparent video
// Final video will be 10 seconds (longest foreground)
```
```python Python theme={"dark"}
# Color background adapts to content
bg = Background.from_color('#FF0000', 1920, 1080, 30)
comp = Composition(bg)
comp.add(ten_second_transparent) # 10-second transparent video
comp.add(five_second_transparent) # 5-second transparent video
# Final video will be 10 seconds (longest foreground)
```
### Rule 3: Explicit Duration Override
You can always force a specific duration:
```typescript Node.js theme={"dark"}
const comp = new Composition(anyBackground)
comp.setDuration(20.0) // Force 20-second duration
comp.add(transparent)
// Final video will be exactly 20 seconds
```
```python Python theme={"dark"}
comp = Composition(any_background)
comp.set_duration(20.0) # Force 20-second duration
comp.add(transparent)
# Final video will be exactly 20 seconds
```
## Source Trimming
Use only specific parts of your source videos:
### Basic Trimming
```typescript Node.js theme={"dark"}
// Method 1: Trim the foreground before adding
const trimmed = video.subclip(10, 20) // Use seconds 10-20
comp.add(trimmed, 'segment')
// Method 2: Trim in the composition
comp.add(transparent).subclip(10, 20)
// Method 3: Open-ended trim (from 5s to end)
comp.add(transparent).subclip(5)
```
```python Python theme={"dark"}
# Method 1: Trim the foreground before adding
trimmed = transparent.subclip(10, 20) # Use seconds 10-20
comp.add(trimmed, 'segment')
# Method 2: Trim in the composition
comp.add(transparent).subclip(10, 20)
# Method 3: Open-ended trim (from 5s to end)
comp.add(transparent).subclip(5)
```
### Advanced Trimming
```typescript Node.js theme={"dark"}
// Multiple segments from same source
comp.add(transparent).subclip(0, 3).start(0) // 0-3s of source at 0s
comp.add(transparent).subclip(10, 15).start(5) // 10-15s of source at 5s
comp.add(transparent).subclip(25, 30).start(12) // 25-30s of source at 12s
// Re-trimming (trim a trimmed video)
const firstTrim = transparent.subclip(5, 20) // 5-20s of original
const secondTrim = firstTrim.subclip(2, 8) // 2-8s of first trim = 7-13s of original
```
```python Python theme={"dark"}
# Multiple segments from same source
comp.add(transparent).subclip(0, 3).start(0) # 0-3s of source at 0s
comp.add(transparent).subclip(10, 15).start(5) # 10-15s of source at 5s
comp.add(transparent).subclip(25, 30).start(12) # 25-30s of source at 12s
# Re-trimming (trim a trimmed video)
first_trim = transparent.subclip(5, 20) # 5-20s of original
second_trim = first_trim.subclip(2, 8) # 2-8s of first trim = 7-13s of original
```
## Audio Synchronization
Control audio timing with your video layers:
### Audio with Timing
```typescript Node.js theme={"dark"}
// Transparent video with audio that starts at 3 seconds
comp.add(transparent)
.start(3.0)
.audio(true, 1.0) // Audio automatically delayed to match video
// Multiple audio sources with different timing
comp.add(transparent1).start(0).audio(true, 0.8) // Main audio
comp.add(transparent2).start(5).audio(true, 0.3) // Background music
comp.add(transparent3).start(10).audio(true, 0.5) // Sound effects
```
```python Python theme={"dark"}
# Transparent video with audio that starts at 3 seconds
comp.add(transparent) \
.start(3.0) \
.audio(enabled=True, volume=1.0) # Audio automatically delayed to match video
# Multiple audio sources with different timing
comp.add(transparent1).start(0).audio(enabled=True, volume=0.8) # Main audio
comp.add(transparent2).start(5).audio(enabled=True, volume=0.3) # Background music
comp.add(transparent3).start(10).audio(enabled=True, volume=0.5) # Sound effects
```
### Audio Mixing
The system automatically mixes audio from multiple layers:
* **Single audio source**: Used directly
* **Multiple audio sources**: Mixed with volume control
* **Timing**: Audio delays automatically match video timing
## Performance Tips
### Optimize for Speed
* **Shorter segments**: Trim videos to only needed parts
* **Reasonable overlaps**: Avoid too many overlapping layers
* **Fast encoding**: Use faster encoder presets for testing
### Memory Management
* **Large videos**: Consider trimming before composition
* **Many layers**: Test with fewer layers first
* **Long compositions**: Break into segments if needed
## What's Next?
Choose the right export format and quality settings
Explore complete timing and animation examples