R-forks-to-learn / av

Working with Video in R

av

R Bindings to FFmpeg

Installation

You can install av from CRAN

install.packages("av")

You can install the development version from GitHub with:

# Install from GitHub
remotes::install_github("ropensci/av")

Demo Video

Generate a demo video with some random plots and free demo music:

av::av_demo()

This demo is totally lame, please open a PR with something better (in base R!).

Using gganimate

You can use av_encode_video() as the renderer in gganimate:

# Create the gganimate plot
library(gganimate)
p <- ggplot(airquality, aes(Day, Temp)) + 
  geom_line(size = 2, colour = 'steelblue') + 
  transition_states(Month, 4, 1) + 
  shadow_mark(size = 1, colour = 'grey')

# Render and show the video
q <- 2
df <- animate(p, renderer = av_renderer('animation.mp4'), width = 720*q, height = 480*q, res = 72*q, fps = 25)
utils::browseURL('animation.mp4')

Video Filters

You can add a custom ffmpeg video filter chain. For example this will negate the colors, and applies an orange fade-in effect to the first 15 frames.

# Continue on the example above
filter_render <- av_renderer('orange.mp4', vfilter = 'negate=1, fade=in:0:15:color=orange')
df <- animate(p, renderer = filter_render, width = 720*q, height = 480*q, res = 72*q, fps = 25)
av::av_video_info('orange.mp4')
utils::browseURL('orange.mp4')

Filters can also affect the final fps of the video. For example this filter will double fps because it halves presentation the timestamp (pts) of each frame. Hence the output framerate is actually 50!

fast_render <- av_renderer('fast.mp4', vfilter = "setpts=0.5*PTS")
df <- animate(p, renderer = fast_render, fps = 25)
av::av_video_info('fast.mp4')
utils::browseURL('fast.mp4')

Capture Graphics (without gganimate)

Instead of using gganimate, we can use av_capture_graphics() to automatically record R graphics and turn them into a video. This example makes 12 plots and adds an interpolation filter to smoothen the transitions between the frames.

library(gapminder)
library(ggplot2)
makeplot <- function(){
  datalist <- split(gapminder, gapminder$year)
  lapply(datalist, function(data){
    p <- ggplot(data, aes(gdpPercap, lifeExp, size = pop, color = continent)) +
      scale_size("population", limits = range(gapminder$pop)) + geom_point() + ylim(20, 90) +
      scale_x_log10(limits = range(gapminder$gdpPercap)) + ggtitle(data$year) + theme_classic()
    print(p)
  })
}

# Play 1 plot per sec, and use an interpolation filter to convert into 10 fps
video_file <- file.path(tempdir(), 'output.mp4')
av::av_capture_graphics(makeplot(), video_file, 1280, 720, res = 144, vfilter = 'framerate=fps=10')
av::av_video_info(video_file)
utils::browseURL(video_file)