wiki:Xfade

The xfade and xfade_opencl filters can create transitions between two inputs with various wipes, slides, crossfades, and other effects.

Offset Parameter

The offset parameter determines when the crossfade starts.

It should be set to a value that enables the full duration of the transition between the two videos. The offset parameter in the first video stream should not be greater than the duration of the first video minus the duration of the transition itself.

For example, if your first video is 8 seconds long, and your transition is 1 second long, the offset must be less than or equal to (8-1) = 7.

Also, the duration of the second video should be at least as long as the duration of the transition itself, meaning that in the above example, the second video's duration must be equal to or greater than 1.

To calculate the offset for subsequent videos, you have to factor in the previous crossfade offsets and the duration of the current video. See this example on Stack Overflow.

Examples

MP4 output

Fade between two images. Each image has a duration of 5 seconds. The fade duration is set to 1 second with the duration option, and it occurs at 4 seconds using the offset option.

ffmpeg -loop 1 -t 5 -i 1.png -loop 1 -t 5 -i 2.png -filter_complex "[0][1]xfade=transition=fade:duration=1:offset=4,format=yuv420p" output.mp4

GIF output

Using the split, palettegen, and paletteuse filters:

ffmpeg -loop 1 -t 5 -i 1.png -loop 1 -t 5 -i 2.png -filter_complex "[0][1]xfade=transition=fade:duration=1:offset=4,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" -loop 0 output.gif

Gallery

Below is gallery of the available effects. fade is the default transition. Names in bold are also available in xfade_opencl.

fade (default) fadeblack fadewhite distance
wipeleft wiperight wipeup wipedown
slideleft slideright slideup slidedown
smoothleft smoothright smoothup smoothdown
circlecrop rectcrop circleclose circleopen
horzclose horzopen vertclose vertopen
diagbl diagbr diagtl diagtr
hlslice hrslice vuslice vdslice
dissolve pixelize radial hblur
wipetl wipetr wipebl wipebr
zoomin transition for xfade
fadegrays squeezev squeezeh zoomin
hlwind hrwind vuwind vdwind
coverleft coverright coverup coverdown
revealleft revealright revealup revealdown

Command used to make each gallery image; as reference for future gallery additions:

ffmpeg -f lavfi -i "color=c=blue:s=180x136:r=15:d=2,format=rgb24,drawtext=text='fadeblack':x=(w-text_w)/2:y=(h-text_h)/2:box=1:boxborderw=4:boxcolor=white:fontfile=/usr/share/fonts/TTF/VeraMono.ttf:fontsize=20" -f lavfi -i "color=c=aqua:s=180x136:r=15:d=2,format=rgb24,drawtext=text='fadeblack':x=(w-text_w)/2:y=(h-text_h)/2:box=1:boxborderw=4:boxcolor=white:fontfile=/usr/share/fonts/TTF/VeraMono.ttf:fontsize=20" -filter_complex "[0][1]xfade=duration=1:offset=1:transition=fadeblack,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" fadeblack.gif

Custom effects

You can make your own custom effects using transition=custom and the expr options. See the xfade documentation for more info.

xfade_opencl

xfade_opencl is the Open CL variant of the xfade filter. This filter supports a subset of the filters available in xfade (see bold names in gallery above) and also supports creation of custom effects. It requires ffmpeg to be configured with --enable-opencl and you must initialize a hardware device in your command. See OpenCL Video Filters for general info.

Last modified 6 months ago Last modified on Oct 11, 2023, 2:52:13 PM

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