av
R Bindings to FFmpeg
Installation
You can install av from CRAN
install.packages("av")On Debian/Ubuntu you first need to install libavfilter-dev
sudo apt-get install libavfilter-dev
And on Fedora / CentOS / RHEL you need to install ffmpeg-devel from rpmfusion. See instructions here on how to enable rpmfusion via the command line.
# Need to enable rpmfusion repository first via link above!
sudo yum install ffmpeg-devel
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)
library(transformr)
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_media_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_media_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_media_info(video_file)
utils::browseURL(video_file)