Play simultaneous sounds on Pi4b via XOJO

General
#1

I am trying to simulate an elevator as an art installation. As the sound function in XoJo doesn’t seem to work with Pi, is there a way to play two different sound files at the same time on the Pi4 via Xojo? For example, elevator music with sound effects overlaid. Thanks for any help.

Matt

#2

You can use the shell cass to run omxplayer

#3

Thanks for the suggestion. I tried that, and was able to play one sound file, but the XOJO program was then unresponsive until the sound stopped playing. I was unable to play a second file at the same time as the first.

Matt

#4

Use the shell.executemode = shell.executemodes.interactive

you’ll have full control of the sound/video with omxplayer.
You can have multiple shell class instances at the same time, so mutiple sounds.

https://documentation.xojo.com/api/os/shell.html#shell-executeMode

Interactive means; keep running so that you can send control characters and data (string) to the shell while it’s running using shell.write() or shell.writeline()
This way to can send; stop, pause, start, volume etc…

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#5

For lightweight but powerful audio playback you could use sox ‘play’ command:
https://manpages.debian.org/jessie/sox/play.1.en.html

sudo apt-get install sox
you may also need for mp3 playback:
sudo apt-get install libsox-fmt-mp3

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#6

Thanks Derk and Ian.

Now I have something to try. Was completely stuck…

Matt

#7

I was able to use multiple shells with Omxplayer to play simultaneous music files! Thanks Derk for getting me going again.

A further question; How do I send “key bindings” via that same shell to change volume, etc.?

Matt

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#8

Send the ascii codes for the keys using shell.writeline

#9

Still not getting the results I want. For example “p” should pause/resume playing in Oxmplayer. I tried:

s = new shell
s.ExecuteMode = Shell.ExecuteModes.Interactive
s.Execute (“omxplayer /home/pi/Desktop/Music/‘03 Just Like Heaven 1.mp3’”)

Which starts playing the song. Then tried to pause it this way:

s.writeline (Chr(112)) //“p” character

And nothing happens…

Can you give me an example of how to use the write-in command for this?

Thanks again for your help

#10

try:

s = new shell
s.ExecuteMode = Shell.ExecuteModes.Interactive
s.Canonical = True // ALLOW CONTROL characters to be send, important!
s.Execute("/usr/bin/omxplayer ""/home/pi/Desktop/Music/‘03 Just Like Heaven 1.mp3""")
s.WriteLine("p") // pause you may get a datavailable event giving you some info about the state of 
// omxplayer.

you need the FULL shell path to omxplayer and to the mp3 file in quotes (if it has spaces)

Docs:

#11