[英]Stream FM Radio on Raspberry Pi, Changing Frequency without Restarting
我正在播放FM廣播,並嘗試在流傳輸時更改Raspberry Pi 3的RTL-SDR頻率(即,無需關閉程序並重新啟動)
當前正在播放電台,我可以緩慢增加電台/頻率。 但是,如果我增加得太快,SDR將停止播放。
我正在使用:
我的代碼當前為:
import os
import time
import subprocess
from pi_encoder import *
def updateStation(station_addr, kill=0):
print 'creating pipe1a'
pipe1a = subprocess.Popen(['rtl_fm', '-M', 'wbfm', '-f', str(station_addr) + 'M', '-g', '10'], stdout=subprocess.PIPE)
print 'creating pipe1b'
pipe1b = subprocess.Popen(['play', '-r', '32k', '-t', 'raw', '-e', 's', '-b', '16', '-c', '1', '-V1', '-'], stdin=pipe1a.stdout, stdout=subprocess.PIPE)
print 'creating pipe1c'
pipe1c = pipe1b.stdout
pid_a = pipe1a.pid
return pid_a, pipe1a
# Export LD_LIBRARY_PATH; doesn't seem to retain
os.system('export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib')
## Rotary encoder GPIO PIN assignments are set in 'pi_encoder' module
## SET INITIAL VALUES
tuner_value = 0
station_addr = 95.1
max_tuner_addr = 109.1
min_tuner_addr = 88.0
## INITIALIZE ROTARY ENCODER WORKER THREAD
tuner_encoder = EncoderWorker(SwitchEncoder(TUNER_CLK_PIN, TUNER_DT_PIN, TUNER_SW_PIN))
tuner_encoder.start()
## MAIN LOOP
try:
print 'Starting main loop'
pid, process = updateStation(station_addr)
while True:
delta_tuner = tuner_encoder.get_delta()
if delta_tuner!=0:
tuner_value = tuner_value + delta_tuner
print "tuner value", tuner_value
station_addr = station_addr + (delta_tuner/10.0)
if station_addr > max_tuner_addr:
station_addr = max_tuner_addr
elif station_addr < min_tuner_addr:
station_addr = min_tuner_addr
print 'station_address: ', station_addr
print 'terminating process:'
process.terminate()
try:
os.kill(pid, 0)
process.kill()
except OSError, e:
print 'Terminated gracefully'
pid, process = updateStation(station_addr)
if tuner_encoder.get_upEvent():
print "tuner up!"
if tuner_encoder.get_downEvent():
print "tuner down!"
finally:
print 'Cleaning up GPIO...'
IO.cleanup()
python子進程可以容忍這種用法嗎?
是否有另一種方式(命令,方法,庫)可以更平滑,更快速地更改電台/頻率,而不影響播放或停止播放SDR?
在使用updateStation調用啟動新進程之前,您可能需要找到一種方法來等待process.kill()完成和管道關閉(異步發生)。 嘗試在執行任何殺死操作后在main while()循環中稍加延遲,以防止其發送進程命令的速度超過操作系統能夠可靠處理的速度。
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