No Audio Output on Kivy Applications Running on a Rasperry Pi Jesse - raspberry-pi

Question

Esteemed Colleagues --
I hope you're doing well. I'm hoping you can help me figure out a weird audio issue running Kivy on Raspberry Pi. In a nutshell, I can't get Kivy to produce any audio running on Raspberry Pi. I'm not sure on other hardware as I'm only developing on RPi. My code is below. This is just a simple soundboard app. Press a button and it plays a file. It should work in theory, but it doesn't. I have read every single relevant StackOverflow and Reddit post. I've tried dozens of variations of my code. No matter what I do Kivy is still as silent as mouse.
Here is what I'm running:
Raspberry Pi 3 Model B
Rasbian -- Linux raspberrypi 4.4.38-v7+ #938 SMP Thu Dec 15 15:22:21 GMT 2016 armv7l GNU/Linux
Kivy -- 1.9.2-dev0
What I've tried:
USB Audio & System Audio -- I tried using the system audio (headphone) jack as well as a USB sound card. Specifically, I'm using Plugable USB Headphone Adapter. Yes, my speakers are plugged in to the right ports. I've updated my configuration files to default to the USB adapter as I was getting too much interference from the system board output.
Formats -- I've tried both MP3, WAV, OGG format. No dice.
Playing From Terminal -- I can get the system to produce audio using other methods. I can get Rasbian to play audio as well as on the terminal using mpg321. This command "mpg321 "/home/pi/burnedpi/assets/audio/scotch.mp3" will successfully decode and play the MP3 file.
It will output sound just fine via USB. I've tested my speakers in the terminal with "speaker-test -c2 -t wav" command and they work.
I've adjusted and confirmed my audio internal audio mixer settings in alsmixer. The sound card has the volume properly turned up.
Other Commands and Programs Work -- I'm pretty sure that this issue is just related to Kivy on Pi. Other applications are able to produce sound just fine.
Example
Kivy Audio Applications Don't Work -- The official Kivy audio examples that get installed by default do not produce any audio.
Essentially, I'm just trying to get Kivy to output sound. I've got a real simple script that outputs an audio file when a mouse is clicked.
I'm really stuck and don't know what to do next. Any help would be greatly appreciated.
Cheers.
Steve.
Here is my code.
My spacing/tabs are correct, but Stack makes it hard to format
* main.py *
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ListProperty, ObjectProperty, NumericProperty
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.audio import SoundLoader
class SoundBoard(Screen):
def scotch(self):
sound = SoundLoader.load('../assets/audio/scotch.wav')
if sound:
sound.play()
sound.seek(0.00)
print("Sound found at %s" % sound.source)
print("Sound is %.3f seconds" % sound.length)
print("Sound status %s" % sound.status)
class RootScreen(ScreenManager):
pass
class audio(App):
def build(self):
return SoundBoard()
if __name__ == "__main__":
audio().run()
audio.kv
<RootScreen>
SoundBoard:
<SoundBoard>
name: 'soundboard'
BoxLayout:
Button:
text: 'i love scotch scotchy scotch scotch'
on_press: root.scotch()
* Here is what I get when I run the code: *
pi#raspberrypi:~ $ python burnedpi/audio/main.py
[INFO ] [Logger ] Record log in /home/pi/.kivy/logs/kivy_17-01-11_84.txt
[INFO ] [Image ] Providers: img_tex, img_dds, img_sdl2, img_pil, img_gif (img_ffpyplayer ignored)
[INFO ] [Kivy ] v1.9.2-dev0
[INFO ] [Python ] v2.7.9 (default, Sep 17 2016, 20:26:04)
[GCC 4.9.2]
[INFO ] [Factory ] 193 symbols loaded
[INFO ] [Text ] Provider: sdl2
[INFO ] [AudioGstplayer] Using Gstreamer 1.4.4.0
[INFO ] [Audio ] Providers: audio_gstplayer, audio_sdl2 (audio_ffpyplayer ignored)
[INFO ] [Window ] Provider: egl_rpi
[INFO ] [GL ] Using the "OpenGL ES 2" graphics system
[INFO ] [GL ] Backend used <gl>
[INFO ] [GL ] OpenGL version <OpenGL ES 2.0>
[INFO ] [GL ] OpenGL vendor <Broadcom>
[INFO ] [GL ] OpenGL renderer <VideoCore IV HW>
[INFO ] [GL ] OpenGL parsed version: 2, 0
[INFO ] [GL ] Shading version <OpenGL ES GLSL ES 1.00>
[INFO ] [GL ] Texture max size <2048>
[INFO ] [GL ] Texture max units <8>
[INFO ] [Shader ] fragment shader: <Compiled>
[INFO ] [Shader ] vertex shader: <Compiled>
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
[INFO ] [OSC ] using <multiprocessing> for socket
[INFO ] [ProbeSysfs ] device match: /dev/input/event0
[INFO ] [MTD ] Read event from </dev/input/event0>
[INFO ] [ProbeSysfs ] device match: /dev/input/event1
[INFO ] [MTD ] Read event from </dev/input/event1>
[INFO ] [ProbeSysfs ] device match: /dev/input/event0
[INFO ] [HIDInput ] Read event from </dev/input/event0>
[INFO ] [ProbeSysfs ] device match: /dev/input/event1
[INFO ] [HIDInput ] Read event from </dev/input/event1>
[INFO ] [Base ] Start application main loop
[INFO ] [MTD ] </dev/input/event0> range position X is 0 - 800
[INFO ] [MTD ] </dev/input/event0> range position Y is 0 - 480
[INFO ] [MTD ] </dev/input/event0> range touch major is 0 - 0
[INFO ] [MTD ] </dev/input/event0> range touch minor is 0 - 0
[INFO ] [MTD ] </dev/input/event0> range pressure is 0 - 255
[INFO ] [MTD ] </dev/input/event0> axes invertion: X is 0, Y is 0
[INFO ] [MTD ] </dev/input/event0> rotation set to 0
[INFO ] [MTD ] </dev/input/event1> range position X is 0 - 0
[INFO ] [MTD ] </dev/input/event1> range position Y is 0 - 0
[INFO ] [HIDMotionEvent] using <FT5406 memory based driver>
[INFO ] [MTD ] </dev/input/event1> range touch major is 0 - 0
[INFO ] [HIDMotionEvent] <FT5406 memory based driver> range ABS X position is 0 - 800
[INFO ] [MTD ] </dev/input/event1> range touch minor is 0 - 0
[INFO ] [HIDMotionEvent] <FT5406 memory based driver> range ABS Y position is 0 - 480
[INFO ] [MTD ] </dev/input/event1> range pressure is 0 - 255
[INFO ] [GL ] NPOT texture support is available
[INFO ] [HIDMotionEvent] <FT5406 memory based driver> range position X is 0 - 800
[INFO ] [MTD ] </dev/input/event1> axes invertion: X is 0, Y is 0
[INFO ] [HIDMotionEvent] <FT5406 memory based driver> range position Y is 0 - 480
[INFO ] [HIDMotionEvent] using <C-Media Electronics Inc. USB Audio Device>
[INFO ] [MTD ] </dev/input/event1> rotation set to 0
Sound found at /home/pi/burnedpi/assets/audio/scotch.wav
Sound is 5.486 seconds
Sound status play
Here is the information from the Kivy Log File
[INFO ] Logger: Record log in /home/pi/.kivy/logs/kivy_17-01-11_84.txt
[INFO ] Image: Providers: img_tex, img_dds, img_sdl2, img_pil, img_gif (img_ffpyplayer ignored)
[INFO ] Kivy: v1.9.2-dev0
[INFO ] Python: v2.7.9 (default, Sep 17 2016, 20:26:04)
[GCC 4.9.2]
[INFO ] Factory: 193 symbols loaded
[INFO ] Text: Provider: sdl2
[INFO ] AudioGstplayer: Using Gstreamer 1.4.4.0
[INFO ] Audio: Providers: audio_gstplayer, audio_sdl2 (audio_ffpyplayer ignored)
[INFO ] Window: Provider: egl_rpi
[INFO ] GL: Using the "OpenGL ES 2" graphics system
[INFO ] GL: Backend used <gl>
[INFO ] GL: OpenGL version <OpenGL ES 2.0>
[INFO ] GL: OpenGL vendor <Broadcom>
[INFO ] GL: OpenGL renderer <VideoCore IV HW>
[INFO ] GL: OpenGL parsed version: 2, 0
[INFO ] GL: Shading version <OpenGL ES GLSL ES 1.00>
[INFO ] GL: Texture max size <2048>
[INFO ] GL: Texture max units <8>
[INFO ] Shader: fragment shader: <Compiled>
[INFO ] Shader: vertex shader: <Compiled>
[INFO ] Window: virtual keyboard not allowed, single mode, not docked
[INFO ] OSC: using <multiprocessing> for socket
[INFO ] ProbeSysfs: device match: /dev/input/event0
[INFO ] MTD: Read event from </dev/input/event0>
[INFO ] ProbeSysfs: device match: /dev/input/event1
[INFO ] MTD: Read event from </dev/input/event1>
[INFO ] ProbeSysfs: device match: /dev/input/event0
[INFO ] HIDInput: Read event from </dev/input/event0>
[INFO ] ProbeSysfs: device match: /dev/input/event1
[INFO ] HIDInput: Read event from </dev/input/event1>
[INFO ] Base: Start application main loop
[INFO ] MTD: </dev/input/event0> range position X is 0 - 800
[INFO ] MTD: </dev/input/event0> range position Y is 0 - 480
[INFO ] MTD: </dev/input/event0> range touch major is 0 - 0
[INFO ] MTD: </dev/input/event0> range touch minor is 0 - 0
[INFO ] MTD: </dev/input/event0> range pressure is 0 - 255
[INFO ] MTD: </dev/input/event0> axes invertion: X is 0, Y is 0
[INFO ] MTD: </dev/input/event0> rotation set to 0
[INFO ] MTD: </dev/input/event1> range position X is 0 - 0
[INFO ] MTD: </dev/input/event1> range position Y is 0 - 0
[INFO ] HIDMotionEvent: using <FT5406 memory based driver>
[INFO ] MTD: </dev/input/event1> range touch major is 0 - 0
[INFO ] HIDMotionEvent: <FT5406 memory based driver> range ABS X position is 0 - 800
[INFO ] MTD: </dev/input/event1> range touch minor is 0 - 0
[INFO ] HIDMotionEvent: <FT5406 memory based driver> range ABS Y position is 0 - 480
[INFO ] MTD: </dev/input/event1> range pressure is 0 - 255
[INFO ] GL: NPOT texture support is available
[INFO ] HIDMotionEvent: <FT5406 memory based driver> range position X is 0 - 800
[INFO ] MTD: </dev/input/event1> axes invertion: X is 0, Y is 0
[INFO ] HIDMotionEvent: <FT5406 memory based driver> range position Y is 0 - 480
[INFO ] HIDMotionEvent: using <C-Media Electronics Inc. USB Audio Device>
[INFO ] MTD: </dev/input/event1> rotation set to 0
[INFO ] Base: Leaving application in progress...
[WARNING] stderr: Traceback (most recent call last):
[WARNING] stderr: File "burnedpi/audio/main.py", line 27, in <module>
[WARNING] stderr: audio().run()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/app.py", line 828, in run
[WARNING] stderr: runTouchApp()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/base.py", line 504, in runTouchApp
[WARNING] stderr: EventLoop.window.mainloop()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/core/window/window_egl_rpi.py", line 90, in mainloop
[WARNING] stderr: self._mainloop()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/core/window/window_egl_rpi.py", line 85, in _mainloop
[WARNING] stderr: EventLoop.idle()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/base.py", line 339, in idle
[WARNING] stderr: Clock.tick()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/clock.py", line 553, in tick
[WARNING] stderr: current = self.idle()
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/clock.py", line 533, in idle
[WARNING] stderr: usleep(1000000 * sleeptime)
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/clock.py", line 717, in usleep
[WARNING] stderr: _usleep(microseconds, self._sleep_obj)
[WARNING] stderr: File "/usr/local/lib/python2.7/dist-packages/kivy/clock.py", line 445, in _usleep
[WARNING] stderr: _libc_usleep(int(microseconds))
[WARNING] stderr: KeyboardInterrupt

Answer 1

Figured it out. Set the enviromental variable prior to importing Kivy. Add this to the top of the file.
import os
os.environ['KIVY_AUDIO'] = 'sdl2'
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ListProperty, ObjectProperty, NumericProperty
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.audio import SoundLoader
class SoundBoard(Screen):
def scotch(self):
sound = SoundLoader.load('../assets/audio/scotch.wav')
if sound:
sound.play()
sound.seek(0.00)
print("Sound found at %s" % sound.source)
print("Sound is %.3f seconds" % sound.length)
print("Sound status %s" % sound.status)
class RootScreen(ScreenManager):
pass
class audio(App):
def build(self):
return SoundBoard()
if __name__ == "__main__":
audio().run()
Make sure you set your environmental variables prior to importing Kivy. Use this format:
import os
os.environ['KIVY_AUDIO'] = 'sdl2'
Check out https://kivy.org/docs/guide/environment.html for more information.