makemovie: Produce a movie from frame-drawing function

In obreschkow/cooltools: Practical Tools for Scientific Computations and Visualizations

Produce a movie from frame-drawing function

Description

Generates an MP4-movie provided a custom function that plots individual frames. The routine has been developed and tested for MacOS and it requires on a working installation of ffmpeg.

Usage

makemovie(
  frame.draw,
  frame.index,
  output.path,
  output.filename,
  width = 1080,
  height = 720,
  fps = 60,
  keep.frames = FALSE,
  quiet = FALSE,
  separator = "/",
  ffmpeg.cmd = "ffmpeg",
  ffmpeg.opt = "-vcodec libx264 -crf 18 -pix_fmt yuv420p",
  manual = FALSE,
  cex = 1,
  oversampling = 1,
  first.index = 1,
  last.index = length(frame.index)
)

Arguments

frame.draw	function that plots an individual frame. This function must have exactly one argument 'x', which can be integer (e.g. a simple frame index) or real (e.g. a time).
frame.index	list of frame indices 'x' to be included in the movie
output.path	character specifying the directory, where the movie and temporary frames are saved
output.filename	movie filename without path. This filename should end on the extension '.mp4'.
width	integer number of pixels along the horizontal axis
height	integer number of pixels along the vertical axis
fps	number of frames per second
keep.frames	logical flag specifying whether the temporary directory with the individual frame files should be kept. If manual is set to TRUE, the frames are always kept.
quiet	logical flag; if true, all console outputs produced by 'ffmpeg' are suppressed
separator	filename separate of the system ('/' for Mac, Linux, Unix; '\' for Windows)
ffmpeg.cmd	command used to call ffmpeg form a terminal. Normally, this is just 'ffmpeg'.
ffmpeg.opt	compression and formatting options used with ffmpeg
manual	logical flag; if true, ffmpeg is not called from within the code and the frames are never deleted. The suggested linux command line is returned as output.
cex	number defining the overall scaling of line widths, font sizes, etc.
oversampling	integer specifying the oversampling factor along both dimensions. If larger than 1, frames are plotted with (width*oversampling)-by-(height*oversampling) pixels and then resized back to width-by-height. This can be used to make line objects and text move more smoothly.
first.index	integer specifying the first index of the vector frame.index to consider. Choosing a value larger than the default (1) can be used to continue a previously interrupted call of makemovie and/or to call makemovie from different R sessions in parallel.
last.index	integer specifying the last index of the vector frame.index to consider. Choosing a value smaller than the default (length(frame.index)) can be used to continue a previously interrupted call of makemovie and/or to call makemovie from different R sessions in parallel.

Value

Linux command line to convert frames into movie using ffmpeg.

Author(s)

Danail Obreschkow

See Also

makeframe

Examples

## Example: Movie of a manual clock

# Function to draw a single clock face with two hands
frame = function(time) {
  oldpar = graphics::par(mar=c(0,0,0,0))
  nplot(xlim=c(-1.1,1.1),ylim=c(-1.1,1.1),pty='s')
  plotrix::draw.circle(0,0,1,col='#aaaaff')
  radius = c(0.5,0.9)
  speed = 2*pi/c(720,60)
  lwd = c(4,2)
  graphics::arrows(0,0,radius*sin(speed*time),radius*cos(speed*time),lwd=lwd)
  graphics::par(oldpar)
}

# Produce movie
## Not run: 
makemovie(frame,seq(0,60,0.5),'~/testmovie','movie.mp4',200,200)

## End(Not run)

obreschkow/cooltools documentation built on Nov. 16, 2024, 2:46 a.m.