Running pyfluidsynth + pyaudio demo, many problems with alsa and jack

问题

I'm following the demo here. I'm very new to creating audio via python, so I'm not sure how to debug which errors I should consider, what naive things I might be doing wrong.

Here are my python errors:

>>> import time
>>> import numpy
>>> import pyaudio
>>> import fluidsynth
>>> 
>>> pa = pyaudio.PyAudio()
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
jack server is not running or cannot be started
>>> strm = pa.open(
...     format = pyaudio.paInt16,
...     channels = 2, 
...     rate = 44100, 
...     output = True)
>>> 
>>> s = []
>>> 
>>> fl = fluidsynth.Synth()
>>> 
>>> # Initial silence is 1 second
... s = numpy.append(s, fl.get_samples(44100 * 1))
>>> 
>>> sfid = fl.sfload("example.sf2")
fluidsynth: error: Unable to open file "example.sf2"
fluidsynth: error: Couldn't load soundfont file
fluidsynth: error: Failed to load SoundFont "example.sf2"
>>> fl.program_select(0, sfid, 0, 0)
fluidsynth: error: There is no preset with bank number 0 and preset number 0 in SoundFont -1
-1
>>> 
>>> fl.noteon(0, 60, 30)
-1
>>> fl.noteon(0, 67, 30)
-1
>>> fl.noteon(0, 76, 30)
-1
>>> 
>>> # Chord is held for 2 seconds
... s = numpy.append(s, fl.get_samples(44100 * 2))

I have pyaudio, fluidsynth, pyfluidsynth installed successfully, and am running ubuntu 12.10 if that makes any difference.

来源：https://stackoverflow.com/questions/20023545/running-pyfluidsynth-pyaudio-demo-many-problems-with-alsa-and-jack