Pardon the bump...anyone have any ideas?
On 9/13/07, Steven Clark <[EMAIL PROTECTED]> wrote:
>
> Hi all-
>
> I am testing out the blks2.mod_pkts & blks2.demod_pkts with something
> similar to what is in the benchmark_loopback example, only I do not use the
> USRP at all. Basically, I am transfering the contents of one audio file to
> another by way of a mod/demod packet chain, and hoping to see the same
> complete, intact audio file come out the other side. Relevant code follows:
>
> class gmsk_tester(gr.top_block):
> def __init__(self, rx_callback):
> gr.top_block.__init__(self, "gmsk_tester")
>
> self.mod = gmsk_mod()
> self.pkt_tx = mod_pkts(self.mod )
>
> self.demod = gmsk_demod()
> self.pkt_rx = demod_pkts(self.demod, callback=rx_callback)
>
> self.connect(self.pkt_tx, self.pkt_rx)
>
>
> def main():
> src_fn = 'data.ogg '
> dst_fn = 'data2.ogg'
>
> src_file = file(src_fn, 'r')
> src_data = src_file.read()
> src_file.close()
>
> global dst_file
> dst_file = file(dst_fn, 'w')
>
> def rx_callback(ok, payload):
> global dst_file
> dst_file.write(payload)
>
> gt = gmsk_tester(rx_callback)
>
> gt.start()
>
> try:
> i = 0
> pkt_size = 800
> pkt_data = src_data[i:i+pkt_size]
> while len(pkt_data) > 0:
> print len(pkt_data)
> gt.pkt_tx.send_pkt(pkt_data)
> i = i+pkt_size
> pkt_data = src_data[i:i+pkt_size]
> except:
> pass
>
> gt.pkt_tx.send_pkt('')
>
> gt.pkt_tx.send_pkt(eof=True)
>
> gt.wait()
>
> #time.sleep(1)
>
> dst_file.flush()
>
> if __name__ == '__main__':
> main()
>
>
> Sometimes this code runs to completion without complaint, sometimes at the
> end I get:
> Exception in thread Thread-1 (most likely raised during interpreter
> shutdown):
> Traceback (most recent call last):
> File "threading.py", line 460, in __bootstrap
> File "/usr/local/lib/python2.5/site-packages/gnuradio/blksimpl2/pkt.py",
> line 153, in run
> <type 'exceptions.AttributeError'>: 'NoneType' object has no attribute
> 'unmake_packet'
> Unhandled exception in thread started by
> Error in sys.excepthook:
>
> Original exception was:
>
>
> If I uncomment the sleep, I never see this message. So:
> Q1) Any idea what this error is all about? Is this a race condition that
> needs to be addressed, or am I doing something wrong?
>
> Q2) The original audio file is 350.0KB. Sometimes the resulting audio file
> is complete, other times it never gets the last few KB (ends up 341.0KB,
> for example). How do I ensure that all the bytes make it across
> successfully?
>
> Q3) What is the effect of packet size? Is there an optimum size? A max
> size? For USRP, packets need to be padded to a multiple of XXX?
>
> Q4) Some examples use gr.enable_realtime_scheduling(). What is the effect
> of this, and do I need it? I note that it requires a sudo.
>
> Thanks for your time!
> -Steven
>
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