vid.to.images2: Extracts images from a video file with ffmpeg

In trackter: Automated Kinematic Analysis of Image Data

Description

Extract images from video file using ffmpegs flexible video filters and codecs

Usage

vid.to.images2(
  vid.path = NULL,
  out.dir = NULL,
  overwrite = FALSE,
  filt = NULL,
  codec = NULL,
  silent = TRUE
)

Arguments

vid.path	character; path of video file to be processed.
out.dir	character; directory path in which to store images.
overwrite	logical; should path described by 'out.dir' be overwritten if it exhists.
filt	character; video filter that should be applied to ffmpeg operation. See https://ffmpeg.org/ffmpeg-filters.html
codec	character; video codec to apply in ffmpeg operation
silent	logical; should output of system call for ffmpeg operation be suppressed.

Details

Particularly useful for resizing images

Value

Extracts all the images of the video and saves them to an "images" directory with appended number sequence

See Also

images.to.video

Examples

#make a video with animation package

fun <- function(){
y <- sin(1:50)
x <- 1:50
for(i in 1:50) {
  plot(x[i],y[i],col="red",xlim=c(0,50),ylim=range(y))
  animation::ani.pause()
  }
}
animation::saveVideo(fun(),video.name=paste0(tempdir(),"/wave.mp4"),interval = 0.2)

#reduce the image images to 200 px wide maintaining aspect ratio
#notice the spaces at the beginning/end of string
filt.red <- " -vf scale=200:-1 "
c <- " -c:v libx264 "
dir.create(paste0(tempdir(),"/images"))
vid.to.images2(vid.path=paste0(tempdir(),"/wave.mp4"),
out.dir=paste0(tempdir(),"/images"),filt=filt.red,codec=NULL)

#see the images in the "images" directory
list.files( paste0(tempdir(),"/images"))

#clean up
unlink(paste0(tempdir(),"/images"),recursive=TRUE)

trackter documentation built on April 19, 2021, 1:08 a.m.