Laggy Audio Stream on RaspberryPi

[ds1982]

After managing to install the spottily gem (see #27) i am now able to play Musik with the delivered examples.

Unfortunaly it is very laggy, The Playback stops every few seconds and starts after further 2-3 seconds again.

"top" shows ~90% cpu-usage by ruby-process. Any hints?

[Burgestrand]

Yes. The audio example is too low performance to work on raspberry pi, the processor is simply not fast enough.

I have two experimental branches since checking this problem out a few weeks ago:

• spotify gem: https://github.com/Burgestrand/spotify/tree/raspberry-pi
• plaything gem: https://github.com/Burgestrand/plaything/tree/raspberry-pi

Using the gems from the two experimental versions above allowed me to play audio without lag on raspberry pi. You're welcome to try them.

There have not been a release with these branches, because I'm thinking of possibly merging plaything and the spotify gem... maybe. How to handle audio playback in this library is a bit complex. I want to ship a nice default solution, but still allow people to make advanced custom drivers if they ever want to.

[ds1982]

sorry for double-Posting this issue. I saw that this topic was discussed in some old threads. I will try your branches.

[Burgestrand]

Don't worry. I like to keep this issue open. It reminds me that some change needs to be made for the spotify gem to work well on raspberry pi.

[ds1982]

Tried to use the raspberry-pi branch now without success.

example-audio_delivery_speed.rb seems to work, but i can't hear any audio.
Log:

[INFO @ 22:18:04] Log in requested. Waiting forever until logged in.................................
[INFO @ 22:18:07] Playing track until end. Use ^C to exit.0f of 0f/s (NaNs)
92160f of 44100f/s (2.09s)
137216f of 44100f/s (3.11s)
65536f of 44100f/s (1.49s)
67584f of 44100f/s (1.53s)
65536f of 44100f/s (1.49s)
...

example-audio_stream.rb gives:

/home/pi/spotify/lib/spotify/reaper.rb:73: [BUG] Segmentation fault
ruby 1.9.3p194 (2012-04-20 revision 35410) [arm-linux-eabi]

-- Control frame information -----------------------------------------------
c:0004 p:---- s:0011 b:0011 l:000010 d:000010 CFUNC  :sleep
c:0003 p:0075 s:0007 b:0007 l:0020d0 d:000006 BLOCK  /home/pi/spotify/lib/spotify/reaper.rb:73
c:0002 p:---- s:0004 b:0004 l:000003 d:000003 FINISH
c:0001 p:---- s:0002 b:0002 l:000001 d:000001 TOP   

-- Ruby level backtrace information ----------------------------------------
/home/pi/spotify/lib/spotify/reaper.rb:73:in `block in initialize'
/home/pi/spotify/lib/spotify/reaper.rb:73:in `sleep'

-- C level backtrace information -------------------------------------------

-- Other runtime information -----------------------------------------------

* Loaded script: example-audio_stream.rb

* Loaded features:

    0 enumerator.so
    1 /usr/lib/ruby/1.9.1/arm-linux-eabi/enc/encdb.so
    2 /usr/lib/ruby/1.9.1/arm-linux-eabi/enc/trans/transdb.so
    3 /usr/lib/ruby/1.9.1/rubygems/defaults.rb
...

Any Idea what could be wrong?

[ds1982]

Could you give me some Information with wich OS/Config you tested these branches, so i could replicate this working system?

[Burgestrand]

Hm. I've seen segfaults on Raspberry PI earlier. Last time I had audio playback work, I was actually surprised that it did not segfault, as I recall an earlier attempt caused random segfaults at just about any time.

I can't remember what setup I used earlier. I am fairly certain it was one of the mentioned OSes for the official downloads: http://www.raspberrypi.org/downloads/. Since the branch includes a special version of spotify to support another libspotify version, it is possible hard float was my previous OS.

As far as config goes, I would assume ruby 2.0 was installed, but nothing else.

[ds1982]

Since the branch includes a special version of spotify to support another libspotify version, it is
possible hard float was my previous OS.

So i can use it with libspotify 12.1.103 beta ?

I tried to install this by hand and installed the spottily gem (raspberry branch) but got this:

/home/pi/spotify/lib/spotify.rb:4:in `require': cannot load such file -- libspotify (LoadError)
    from /home/pi/spotify/lib/spotify.rb:4:in `<top (required)>'
    from /home/pi/spotify/examples/support.rb:2:in `require'
    from /home/pi/spotify/examples/support.rb:2:in `<top (required)>'
    from example-audio_stream.rb:4:in `require_relative'
    from example-audio_stream.rb:4:in `<main>'

Do i have to install any libspotify gem too? i could not find any raspberry branch here?

[Burgestrand]

I took a look at it today, and I believe this was my setup:

• Raspbian OS, hard float
• Pure ruby installation of libspotify gem (important, so no binary can be found in the gem)
• Manual installation of hard float libspotify, see instructions here: https://github.com/Burgestrand/spotify/wiki#how-to-install-libspotify — make sure that you correct URL for libspotify depending on hard float/soft float on your OS
• Special branch of spotify gem (https://github.com/Burgestrand/spotify/tree/raspberry-pi), that does not have hard coded version check for libspotify

So i can use it with libspotify 12.1.103 beta ?

Yes. The raspberry pi branch of spotify have removed the hard coded version check. It will no longer crash on boot with a wrong libspotify version error.

[ds1982]

Alright. Can run the examples now.
Problem was the pure-ruby install of libspotify (have this and hf-version of libspotify now installed by hand). All of this on Hardfloat OS.

Another Problem was line 1 in the examples "support.rb"

require "bundler/setup"

with this line libspotify cannot be found. I commented it out and now libspotify and spotify gem runs until a track is played.

Problem now ist: Track is played (dots are running in example_audio_stream.rb) BUT if have NO Audio.
Tried internal Audio and a USB Soundcard.

Log:

[INFO @ 10:23:05] Log in requested. Waiting forever until logged in..
[INFO @ 10:23:05] (session (log message)) 10:23:05.552 I [ap:1752] Connecting to AP ap.spotify.com:4070

[INFO @ 10:23:05] (session (log message)) 10:23:05.710 I [ap:1226] Connected to AP: 78.31.12.22:4070

[INFO @ 10:23:06] (session (log message)) 10:23:06.048 I [offline-mgr:2082] Storage has been cleaned
.......
Spotify track URI: spotify:track:2FltaWSvGlNcVOfzOgFBEg

[INFO @ 10:23:34] Playing track until end. Use ^C to exit...........................
[INFO @ 10:23:35] (session (log message)) 10:23:35.865 I [file_streamer_simple.cpp:769] Request for file fbc9aef693f20babb41cfb82148b7a24028f4a18 complete (code: 0)
..........
[INFO @ 10:23:36] (session (log message)) 10:23:36.423 I [file_streamer_simple.cpp:769] Request for file fbc9aef693f20babb41cfb82148b7a24028f4a18 complete (code: 0)
.........................................................................................^C
[INFO @ 10:23:41] Logging out..........................................
[INFO @ 10:23:43] (session (log message)) 10:23:43.206 I [offline-mgr:2030] 0 files are locked. 0 images are locked

[INFO @ 10:23:43] (session (log message)) 10:23:43.209 I [offline-mgr:2056] 0 files unlocked. 0 images unlocked

Any ideas?

[Burgestrand]

Yeah, I noticed the problem with bundler now too. I just released a new version of libspotify with support for hard float in the gem, so one should not need to install libspotify manually. Unfortunately, there is a bug in rubygems, so it does not install the arm-linux release of libspotify gem, and there is (probably) a bug in bundler, so it ignores the installed libspotify gem with arm-linux platform, and installs pure ruby version. Like you noticed, the fix is manual install of libspotify gem with gem install libspotify --platform arm-linux, and removal of bundler/setup.

Regarding your problem with no audio, I ran into it too and it is solvable. Here are the issues:

1. You must install plaything from raspberry-pi branch. Normally bundler would do this by changing Gemfile.
2. We cannot use bundler, because bundler will install and use pure ruby version of libspotify.

I solved it by doing these steps:

git clone https://github.com/Burgestrand/plaything
cd plaything
git checkout raspberry-pi
rake build # build raspberry-pi gem
gem install pkg/plaything-1.1.1.gem # install raspberry-pi-specific gem globally

After that, you should be able to run the examples, assuming that:

1. You've removed the require 'bundler/setup' line from the examples.
2. You do not have pure ruby version of libspotify gem, only the arm-linux version. Check with gem list libspotify

After all of these steps, I could play a sound file through HDMI speakers. I had slight a little lag like two times during the entire song, but it was mostly okay.

[ds1982]

works.
For some reason i didn't have the plaything gem raspberry-branch installed (even if bundler said that this branch was used).
Installed plaything now by hand works with internal audio plug (not HDMI, can't test it because i don't have any HDMI speakers available).

Thanks for your good support!!!

I will enjoy your gem now!

[Burgestrand]

Nice!

Sorry about the issues. Raspberry PI is a tricky platform, because not many people use it. I want to change audio to be better though, and so that raspberry pi should be able to play audio too without crazy workarounds.

[ds1982]

would it possible to use a USB Soundcard? Do i have to write my own driver for this?

[Burgestrand]

I don't know. I don't have a USB soundcard to try with. Plaything will use the default sound output device for playback by default.

I think if you are able to change default device globally on your raspberry pi, plaything should use this new device.