multilingual-video-dubbing-ffmpeg-video-filters（多语言视频配音 ffmpeg 视频过滤器）

FFmpeg Video Filters Skill

Apply video filters for scaling, cropping, watermarks, speed changes, and visual effects.

When to Use

• Resize videos
• Crop video frames
• Add watermarks or overlays
• Change playback speed
• Apply blur or other effects
• Adjust brightness/contrast

Scaling

# Scale to 720p (maintain aspect ratio)
ffmpeg -i input.mp4 -vf scale=-2:720 output.mp4

# Scale to specific width (maintain aspect ratio)
ffmpeg -i input.mp4 -vf scale=1280:-2 output.mp4

# Scale to exact dimensions (may distort)
ffmpeg -i input.mp4 -vf scale=1920:1080 output.mp4

# Scale with algorithm
ffmpeg -i input.mp4 -vf scale=1280:720:flags=lanczos output.mp4

Cropping

# Crop to 16:9 from center
ffmpeg -i input.mp4 -vf "crop=1920:1080" output.mp4

# Crop with offset (x:y:width:height)
ffmpeg -i input.mp4 -vf "crop=1920:1080:0:0" output.mp4

# Crop from specific position
ffmpeg -i input.mp4 -vf "crop=800:600:100:50" output.mp4

Watermarks and Overlays

# Add image watermark (top-left)
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "overlay=10:10" output.mp4

# Bottom-right watermark
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "overlay=W-w-10:H-h-10" output.mp4

# Center watermark
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "overlay=(W-w)/2:(H-h)/2" output.mp4

Speed Changes

# Speed up 2x
ffmpeg -i input.mp4 -vf "setpts=0.5*PTS" -af "atempo=2.0" output.mp4

# Slow down 0.5x
ffmpeg -i input.mp4 -vf "setpts=2.0*PTS" -af "atempo=0.5" output.mp4

# Speed up video only (no audio)
ffmpeg -i input.mp4 -vf "setpts=0.5*PTS" -an output.mp4

Blur Effects

# Blur entire video
ffmpeg -i input.mp4 -vf "boxblur=10:5" output.mp4

# Blur specific region (coordinates x:y:w:h)
ffmpeg -i input.mp4 -vf "boxblur=10:5:x=100:y=100:w=200:h=200" output.mp4

# Gaussian blur
ffmpeg -i input.mp4 -vf "gblur=sigma=5" output.mp4

Brightness and Contrast

# Adjust brightness and contrast
ffmpeg -i input.mp4 -vf "eq=brightness=0.1:contrast=1.2" output.mp4

# Increase brightness
ffmpeg -i input.mp4 -vf "eq=brightness=0.2" output.mp4

# Adjust saturation
ffmpeg -i input.mp4 -vf "eq=saturation=1.5" output.mp4

Rotation

# Rotate 90 degrees clockwise
ffmpeg -i input.mp4 -vf "transpose=1" output.mp4

# Rotate 90 degrees counter-clockwise
ffmpeg -i input.mp4 -vf "transpose=2" output.mp4

# Rotate 180 degrees
ffmpeg -i input.mp4 -vf "transpose=1,transpose=1" output.mp4

Multiple Filters

# Chain multiple filters
ffmpeg -i input.mp4 -vf "scale=1280:720,crop=800:600:100:50" output.mp4

# Complex filter chain
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "[0:v]scale=1280:720[scaled];[scaled][1:v]overlay=10:10" \
  output.mp4

Fade Effects

# Fade in (first 2 seconds)
ffmpeg -i input.mp4 -vf "fade=t=in:st=0:d=2" output.mp4

# Fade out (last 2 seconds)
ffmpeg -i input.mp4 -vf "fade=t=out:st=10:d=2" output.mp4

# Fade in and out
ffmpeg -i input.mp4 -vf "fade=t=in:st=0:d=2,fade=t=out:st=8:d=2" output.mp4

Notes

• Use -vf for video filters
• Multiple filters separated by commas
• Use -filter_complex for complex operations
• Overlay positions: W=width, H=height, w=overlay width, h=overlay height
• Speed changes require both video (setpts) and audio (atempo) filters