# Can I run an external audio player program from Julia? Or simply playback a sterio .wav file?

**URL:** <https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964>\
**Category:** General Usage\
**Tags:** question\
**Created:** [February 10, 2021, 2:57am UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964 "2021-02-10T02:57:11Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![bionicinnovations1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bionicinnovations1/32/22874_2.png) [@bionicinnovations1](https://discourse.julialang.org/u/bionicinnovations1)\
**Post date:** [February 10, 2021, 2:57am UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/1 "2021-02-10T02:57:12Z")

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I am trying to play a wav file (in stereo) with my sound card (Windows 10), and haven’t been able to work it so far.

WAV.jl doesn’t support playback in Windows, and I can’t seem to work out how to get it working in PortAudio.jl either. It is surprisingly difficult to play back a two channel (stereo) wav file in Julia so far.

So I have decided to use the run command to play VLC player and point it to a file. I can’t even get the run(`vlc.exe`) to work either, not sure if I am in the wrong directory or not…

```julia
cd(dirname(@ __FILE__ ))

run(`calc.exe`) # works fine

run(`vlc.exe`)
ERROR: failed process: Process(`vlc.exe`, ProcessExited(3221225781)) [3221225781]

Stacktrace:
 [1] pipeline_error at .\process.jl:525 [inlined]
 [2] run(::Cmd; wait::Bool) at .\process.jl:440
 [3] run(::Cmd) at .\process.jl:438
 [4] top-level scope at REPL[25]:100: 

```

I put a copy of vlc.exe in the local directory. Note that calc.exe works, so I presume I am working in the wrong directory? If I place my vlc.exe and WaveFile.wav in the “correct” directory, should it work? Or better still, how can I make it work for any directory I choose?

Strangely enough when I do the following:

```julia
cd(dirname(@ __FILE__ ))

path = "D:/Documents/OneDrive/WaveFile.wav"

Threads.@spawn run(`vlc $path`)

julia> Threads.@spawn run(`vlc $path`)
Task (runnable) @0x00000000146dc5d0

```

It says “runnable”, but still no sound comes out. So I really don’t understand where these files need to be, nor why it says it should run but still nothing comes out from my speakers.

I simply want to play .wav files from my sound card, with plans to get this working in a GUI later. I’d be grateful if anyone is able to play stereo though their sound card successfully and could provide a working example.

---

<div class="post-metadata">

**Author:** ![pixel27](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pixel27/32/8902_2.png) [@pixel27](https://discourse.julialang.org/u/pixel27)\
**Post date:** [February 10, 2021, 3:18am UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/2 "2021-02-10T03:18:43Z")

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Try:

```julia
run(`"""C:\Program Files (x86)\VideoLAN\VLC\vlc.exe"""`)

```

That should start VLC. You might need to change the path if you installed it somewhere else.

To pass it the wav file do:

```julia
path = "D:\\Documents\\OneDrive\\WaveFile.wav"
run(`"""C:\Program Files (x86)\VideoLAN\VLC\vlc.exe""" $path`)

```

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<div class="post-metadata">

**Author:** ![bionicinnovations1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bionicinnovations1/32/22874_2.png) [@bionicinnovations1](https://discourse.julialang.org/u/bionicinnovations1)\
**Post date:** [February 10, 2021, 11:57am UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/3 "2021-02-10T11:57:37Z")

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Thank you, that solved the problem. I am very grateful!

I noticed that when you execute it, while the vlc window is open, Julia is busy “evaluating”, and you cannot send a second run command until you close the vlc window.

Is there a run command to exit or close the vlc window, so I can sequence the next wav file to play?

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<div class="post-metadata">

**Author:** ![Iulian.Cioarca](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/iulian.cioarca/32/30166_2.png) [@Iulian.Cioarca](https://discourse.julialang.org/u/Iulian.Cioarca)\
**Post date:** [February 10, 2021, 12:47pm UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/4 "2021-02-10T12:47:52Z")

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You can use @async run(…) If you don’t want to keep the repl busy

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<div class="post-metadata">

**Author:** ![sijo](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@sijo](https://discourse.julialang.org/u/sijo)\
**Post date:** [February 10, 2021, 1:22pm UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/5 "2021-02-10T13:22:48Z")

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I would use one of the following:

1. Ask VLC to exit when finished, and let Julia wait until the command is finished (as you already do):

2. Play the different files with the same VLC instance, and tell Julia to not wait for VLC to exit. To play the first file, use

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<div class="post-metadata">

**Author:** ![bionicinnovations1](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bionicinnovations1/32/22874_2.png) [@bionicinnovations1](https://discourse.julialang.org/u/bionicinnovations1)\
**Post date:** [February 10, 2021, 10:42pm UTC](https://discourse.julialang.org/t/can-i-run-an-external-audio-player-program-from-julia-or-simply-playback-a-sterio-wav-file/54964/6 "2021-02-10T22:42:23Z")

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Thanks for this, it works great! I found the best option is the --play-and-exit option because if I try to put the kill( p ) in the same script, it kills the process before the first file has even completed playing:

```julia
path = "D:\\Documents\\OneDrive\\WaveFile.wav"

p = run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --one-instance $path`, wait=false)
run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --one-instance $path`)
run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --one-instance $path`)
run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --one-instance $path`)
kill(p)

```

Where as --play-and-exit- works great because it opens and closes each session after playing each file:

```julia

run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --play-and-exit $path`) 
run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --play-and-exit $path`) 
run(`"""C:\Program Files\VideoLAN\VLC\vlc.exe""" --play-and-exit $path`) 

```

Thanks for your help!