Hi,
I am working on an application ( half duplex communication ) where i have
two flow graphs receiver and transmitter. the scenario is that the receiver
should always be running but when the application require to send something
the receiver flow-graph should be stopped at that time. the reason for the
receiver flow-graph to be stopped is obvious that it should not receive the
data it is sending. i am using laptop sound card (not usrp).
i am trying to stop the receiver and start it once the transmitter queue
becomes empty but i am getting the following error when i restart the graph
audio_alsa_source[plughw:0,0]: snd_pcm_hw_params failed: File descriptor in
bad state
class receive_graph(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
self.rcvd_pktq = gr.msg_queue()
#
#some processing blocks here
#
self.connect(src,//blocks//,sink)
class transmit_graph(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
audio_rate =8000
self.src = gr.message_source(gr.sizeof_char, msgq_limit)
#
#some processing blocks here
#
speaker = audio.sink(audio_rate, "plughw:0,0");
self.connect(src,//blocks//,speaker)
if __name__ == '__main__':
try:
fg1 = freceive_graph()
fg1.start()
fg= transmit_graph()
fg.start()
try:
while True:
message = raw_input("Enter a message to transmit (Ctrl-D to
exit): ")
fg1.stop() #here i am stopping the receiver
graph
#
# here i am making pkt from the message
#
fg.src.msgq().insert_tail(pkt)
if fg.src.msgq().empty_p():
fg1.start()
except EOFError:
print "\nExiting."
fg.src.msgq().insert_tail(gr.message(1))
fg.wait()
# Main python entry
except KeyboardInterrupt:
pass
--
*Niaz Ahmed*
“We are always more anxious to be distinguished for a talent which we do not
possess, than to be praised for the fifteen which we do possess”* : Mark
Twain <http://thinkexist.com/quotes/mark_twain/>*
* <http://thinkexist.com/quotes/mark_twain/>*
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