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Pi B+ & AMP+ Audio playing with mplayer, not with Python Pygame

Nicolas Jacques

May 13, 2015 02:45

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Hi guys...

Got the Amp+ to work on 5/5/2015 Fresh Raspbian.

A sample MP3 is playing with success with "mplayer" in the Speakers.

Now that i know the Pi and AMP+ are working together, i went back to my project ("Music on hold" audio player)

This project is coded in Python using Pygame as an Audio Module.

When i started the Python App (that was working properly with the Pi standard 3.5mm audio connector prior to the AMP+ Install)

The Python app react properly on screen, but faint static is heard in the Speakers.

When i Kill the Python App, the Static stops.

Here is the result of aplay -l

**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_amp], device 0: HifiBerry AMP HiFi tas5713-hifi-0 []
Subdevices: 0/1
Subdevice #0: subdevice #0

The (simplified) python code is:

import pygame
pygame.mixer.init()
pygame.mixer.music.load("123.mp3")
pygame.mixer.music.play()
**Loop while playing**
pygame.mixer.stop()
pygame.mixer.quit()

I have a visual progress bar that follows the playback speed, but only faint static is heard in the speaker.

The Python App would not run until i deleted the /etc/asound.conf
It was complaining it was old or currupted (deleted it and rebooted)

Any ideas?

Thanks

NJ

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8 comments

• 0
  
  HiFiBerry team May 13, 2015 05:08

  Hi NJ,
  
  unfortunately I don't have any idea what could be the problem here. Somebody from the pygame developers have to look into this as I don't know anything about the internals of this software. I recommend contacting then, maybe they have an idea where to look and what to change.
  
  Best regards
  Daniel
• 0
  
  Nicolas Jacques May 13, 2015 22:56

  Ho! i just realized Pygame is initialized at 22k by default and HifiBerry works at 44.1K.
  
  Let me test that again while forcing at 44.1k...
• 0
  
  HiFiBerry team May 14, 2015 05:09

  This could be the reason for the problem.
  BTW: I wonder why anybody would use 22k sample rate by default.
  
  Best regards
  Daniel
• 0
  
  Nicolas Jacques May 15, 2015 11:03

  Hi again,
  
  Tried initializing Pygame Mixer at 44.1K with no change in behaviour.
  
  I will try to contact them.
  
  in the mean time:
  
  -Can you propose a python audio library that is known to properly outputs MP3 files to HifiBerry AMP+?
  
  -I am trying to find/create a 'mplayer' (in Slave mode) python control wrapper so that the Python app just send command to a known working HifiBerry AMP+ media player.
  
  i'll keep you posted...
  
  NJ
• 0
  
  HiFiBerry team May 15, 2015 14:13

  Many distributions use mpd as player backend. It can be remotely controlled. However, I don't know if there is a Python library for it.
  
  Best regards
  Daniel
• 1
  
  Nicolas Jacques May 16, 2015 20:37

  Hello Again!
  
  Looked into mpd that i did not know about.
  
  Got mpd (server) installed. Confirmed functionality with shell command trough mpc (client).
  
  Then, using python-mp2 library, I was able to control mpd properly, using python Scripting.
  
  I think it will be a better implementation than my previous Pygame attempt.
  
  And all this works properly with a really nice sound on the HifiBerry AMP+
  
  Thanks to all!
  
  NJ
• 0
  
  HiFiBerry team May 16, 2015 21:44

  Good to hear this.
  
  Enjoy your sound and let us know about your final implementation. It could be also interesting for other users.
  
  Best regards
  Daniel
• 0
  
  Alex Bjørlig February 01, 2016 11:58

  Hi Nicolas Jacques. 

  I'm trying to setup the Amp+ to play mp3 files with Python. 

  Can you maybe share the code you used with the python-mp2 library?

   

  Thanks in advance.