Re: [Discuss-gnuradio] Usage of Message Queues
Thank you again for your answer. I looked up the Header File of gr_message and it should have the msg() attribute. But when I tried to access, it gave me the error that this attribute isnt existing. Anyway, I now figured out a way which is enough for me: I converted the returned string to a list of bits, and then conert them to a list of bytes, This gives me back the wanted output stream of the demodulator. -- View this message in context: http://gnuradio.4.n7.nabble.com/Usage-of-Message-Queues-tp39295p39893.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Usage of Message Queues
Thank you much for your answer. Indeed, its a shared pointer. I now figured out, the the only way to get the data is via .to_string(). Though, im stuck again. I use the following code to initialize the queue and message sink: self.sink_queue = gr.msg_queue() self.gr_file_source_0 = gr.file_source(gr.sizeof_char*1, stream, False) self.gr_message_sink_0 = gr.message_sink(gr.sizeof_char*1, self.sink_queue, False) Then I'm putting a DPSK mod and demod between and connect the output of the demod to the message sink: self.connect((self.gr_file_source_0, 0), (self.gr_throttle_0, 0)) self.connect((self.gr_throttle_0, 0), (self.digital_dxpsk_mod_0, 0)) self.connect((self.digital_dxpsk_mod_0, 0), (self.digital_dxpsk_demod_0, 0)) self.connect((self.digital_dxpsk_demod_0, 0), (self.gr_message_sink_0, 0)) So my thought was, that all the messages then should contain one byte (with one bit information). At the end, my code looks like that: tb = top_block() tb.start() while 1: point=tb.sink_queue.delete_head() point=point.to_string() print len(point) The first curiosity is, that the length variates from 2 up to 2048. Can somebody explain why? The next question is, how to i convert the bitvalue of the string to an actual char? -- View this message in context: http://gnuradio.4.n7.nabble.com/Usage-of-Message-Queues-tp39295p39815.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Usage of Message Queues
Am 23.02.2013 17:09, schrieb Hanz: Thank you much for your answer. Indeed, its a shared pointer. I now figured out, the the only way to get the data is via .to_string(). So my thought was, that all the messages then should contain one byte (with one bit information). At the end, my code looks like that: tb = top_block() tb.start() while 1: point=tb.sink_queue.delete_head() point=point.to_string() print len(point) The first curiosity is, that the length variates from 2 up to 2048. Can somebody explain why? The next question is, how to i convert the bitvalue of the string to an actual char? Hi, your code setup with the blocks and connects looks fine to me. Although I have not checked the details of msg_sink I would expect it to process blocks of incomming bytes into messages. So a message can contain an abritrary amount of bytes in it (I think that is why your length varies). Once again speaking for the C++ interface with the method length() you will get the number of elements that this message contains. Then you can usually access the message's data through a call to the msg() function which returns a pointer to a byte array containing the bytes. This will be wrapped to some python code, so check the return type of msg() and try to process this returned data instead of to_string() if you are interested in the data itself. So I think your code should look something like this (not tested, please check agains the actual Python interface documented with Sphinx or Python docstrings): message=tb.sink_queue.delete_head() data=message.msg() length=message.length() for i in xrange(length) : byte=data[i] Hope this gives you an idea on how to use the interface. Martin ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Usage of Message Queues
Im sorry that im pushing my question, but its still unsolved for me and need it for my project.. So again, my message queue is filling, i checked that via tb.sink_queue.count(), but if i want to transfer pop a message, it just returns me that message_sptr thing. Can someone help me on that? I cant find a proper manual how to use the message queues/sinks. Again, thanks in advance for any hints :). -- View this message in context: http://gnuradio.4.n7.nabble.com/Usage-of-Message-Queues-tp39295p39455.html Sent from the GnuRadio mailing list archive at Nabble.com. Hi, I don't know much about messages and it's queues from the python side, but maybe a hint to the C++ side will help you to continue. It appears that the object you get back is a wrapped shared pointer. So basically a pointer to a gr_message which's C++ interface is documented here: http://gnuradio.org/doc/doxygen/classgr__message.html In C++ you can use the shared pointer like a usual pointer to that class so I guess that's the same in gnuradio. Just try if you can get the length of the message with returned_var.length() Usually with the msg() member you return an unsigned char pointer to the actual data of the message. My best guess would be that this is wrapped to a list of numpy's uint8 values. I hope that makes it possible for you to continue. Another possible source might be the QA code for gr_msg_source and gr_msg_sink (if there is any) which should deal with messages in python. Yours Martin ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Usage of Message Queues
Im sorry that im pushing my question, but its still unsolved for me and need it for my project.. So again, my message queue is filling, i checked that via tb.sink_queue.count(), but if i want to transfer pop a message, it just returns me that message_sptr thing. Can someone help me on that? I cant find a proper manual how to use the message queues/sinks. Again, thanks in advance for any hints :). -- View this message in context: http://gnuradio.4.n7.nabble.com/Usage-of-Message-Queues-tp39295p39455.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Usage of Message Queues
Hello! I have another question, this time about message queues. I have a demodulator hooked up to message sink. But when I want to pop a message via tb.sink_queue.delete_head(), its just returning that to me: gnuradio.gr.gnuradio_core_runtime.gr_message_sptr; proxy of lt;Swig Object of type 'gr_message_sptr *' at 0xae276b0 I dont know so much about Python and GnuRadio, but it looks like a Pointer of that SWIG for me. How can I get the value? Thanks in advance -- View this message in context: http://gnuradio.4.n7.nabble.com/Usage-of-Message-Queues-tp39295.html Sent from the GnuRadio mailing list archive at Nabble.com. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
