{howler} is a package that utilises thehowler.js library toplay audio on the modern web.
This package is available on CRAN and r-universe. To install thelatest version:
install.packages("devtools")devtools::install_github("ashbaldry/howler")The HTML way to include an audio file in any shiny application/webpage is to use the<audio> tag. This can generallyonly handle one audio file, and cannot (easily) be manipulated from theserver side.
tags$audio(src ="audio/sound.mp3",type ="audio/mp3",autoplay =NA,controls =NA)howler.js uses theWeb Audio API, andwith this we are able to create an audio player that can solve both ofthe above issues and more:
library(shiny)library(howler)ui<-fluidPage(title ="howler Example",howler(elementId ="sound",tracks =list("Track 1"="audio/track_1.mp3","Track 2"="audio/track_2.mp3"),auto_continue =TRUE,auto_loop =TRUE,seek_ping_rate =1000 ),howlerPreviousButton("sound"),howlerPlayPauseButton("sound"),howlerNextButton("sound"))server<-function(input, output, session) {observe({req(input$sound_seek)if (round(input$sound_seek)==10) {pauseHowl("sound") }elseif (round(input$sound_seek)==20) {changeTrack("sound","Track 2") } })}shinyApp(ui, server)The{howler} package also includes a lightweight modulehowlerModuleUI andhowlerModuleServer thatadds a bit of styling to replicate the style of a standard<audio> HTML player.
All examples are available in theExamplesdirectory and can be run locally by installing the{howler}package: