Added notes and todos

Added the start script which controls the flow of the server application.
Still need to add functionality to listen to audio in the client side.
They will need to listen to serverip:6003

Radio Tuner Notes.md

@@ -0,0 +1,113 @@
+# Radio Tuner Notes
+
+This is how frequencies in the FM spectrum are delegated
+
+| Label     | Frequency |
+| --------- | --------- |
+| Min       | 87.5 MHz  |
+| Max       | 108.0 MHz |
+| Step Size | 100 KHz   |
+
+Since we cannot represent these values in the UI (using the dial element), we will instead use these values and multiply by $10^5$
+
+| Label     | Frequency |
+| --------- | --------- |
+| Min       | 875       |
+| Max       | 1080      |
+| Step Size | 1         |
+
+## Message Format
+I think I would like to implement the GNU-Radio Script as a client server application that binds to some `localhost` port and can operate with the following messages
+
+| Message Format | Description                                                |
+| -------------- | ---------------------------------------------------------- |
+| ?VER;          | Outputs the current version of the server                  |
+| ?STATUS;       | Gets the status of the program                             |
+| ?FREQ;         | Queries the frequency that the program is currently set at |
+| :FREQ=%f;      | Sets the frequency according to the float %f               |
+| :QUIT;         | Shuts down the server                                      |
+
+To test out the server
+
+```bash
+telnet localhost 65432
+```
+
+
+
+## BUGS/ENHANCEMENTS`
+
+**Bug Fix:** Investigate different event handlers because the one that's currently used will send too many frequency set messages over to the server. (Maybe one that's like "when you release the dial...")
+
+**Feature Request:** Favorite radio stations section
+
+**Enhancement:** Listen again once the client closes the connection **[FIXED]**
+
+**Enhancement:** Allow multiple connections to the socket and have the server handle it appropriately
+
+**Enhancement:** Probably should more intelligently receive the number of bytes as opposed to setting it to an arbitrarily high number.
+
+**Enhancement:** Maybe use local sockets? (Nah, this will prevent me from having the Pi contain the radio and controlling from my laptop) **[INVALID]**
+
+**Bug Fix:** Send out full number instead of scientific notation. **[Not Needed]**
+
+**Bug Fix:** Include appropriate error messages for when the client can't connect.
+
+**Bug Fix:** Kick the client back to the connect screen when it disconnects.
+
+## Connect Screen
+
+In this screen the user can input the `IP address` and `Port` that the SDR server is hosted on.
+
+From there, it will confirm if it can connect successfully and if so, it will present the dial screen.
+
+There should be some sort of notification if the client loses connection. Maybe popping them back up into the connect screen.
+
+## Sending Audio Over the Network
+
+This requires the UDP Sink box in GNU Radio. Make sure you set the type to `float`.
+
+To hear the output do the following command:
+
+```bash
+netcat -ul address port | aplay -c num_channels -t raw -r sample_rate -f FLOAT_LE -
+```
+
+This tells netcat to listen to UDP on localhost:port and play it with ALSA with the above settings
+
+My current configuration
+
+| Name               | Value         |
+| ------------------ | ------------- |
+| Address            | x.x.x.x       |
+| Port               | 7654          |
+| Number of Channels | 1             |
+| Sample Rate        | 48000         |
+| Sample Type        | Float         |
+| Endiness           | Little Endian |
+
+### Compressing Audio
+
+Command to convert the raw input stream into a ogg stream in standard output with a bitrate limited to 32 kb/s
+
+```bash
+ffmpeg -f f32le -ar 48k -ac 1 -i pipe:0 -f ogg -ab 32k pipe:1
+```
+
+
+
+## TODO
+
+So we should have the GNURadio program still act as a server to be able to change channels, but this time write the raw audio to a file descriptor from which ffmpeg grabs and compresses it to an ogg stream that gets transmitted over the network.
+
+Current command:
+
+```bash
+ffmpeg -f f32le -ar 48k -ac  1 -i pipe:0 -f ogg -ab 32k pipe:1 < raw_audio_pipe | nc -l 127.0.0.1 6003
+```
+
+Grab audio from named pipe that gnuradio is outputting to, then convert it to ogg and compress it with a 32k bitrate and then send that audio over the network.
+
+
+
+**TODO:** Convert the gnuradio blocks program to be a server again

RadioTuner.pro

@@ -0,0 +1,16 @@
+TEMPLATE = app
+TARGET = RadioTuner
+INCLUDEPATH += .
+
+# The following define makes your compiler warn you if you use any
+# feature of Qt which has been marked as deprecated (the exact warnings
+# depend on your compiler). Please consult the documentation of the
+# deprecated API in order to know how to port your code away from it.
+DEFINES += QT_DEPRECATED_WARNINGS
+
+# Input
+HEADERS += client.h
+SOURCES += client.cpp main.cpp
+RESOURCES += qml.qrc
+
+QT += network qml quick 

client.cpp

@@ -14,7 +14,6 @@ Client::~Client() {
 }
 
 void Client::connect(QString hostname, int port) {
-    assert (port > 0);
     socket->connectToHost(hostname, port);
     socket->waitForConnected();
     std::cout << "Connected" << std::endl;

start

@@ -0,0 +1,24 @@
+#!/bin/bash
+compress=1
+
+function cleanup() {
+	echo "Shutting Down"
+	rm ./raw_audio_pipe
+	kill $child_pid
+}
+
+mkfifo ./raw_audio_pipe
+
+# Run Radio Server Program in Background
+./tuner.py &
+child_pid=$!
+
+if [ $compress -eq 1 ]
+then
+	ffmpeg -f f32le -ar 48k -ac  1 -i pipe:0 -f ogg -ab 32k pipe:1 < ./raw_audio_pipe | nc -kl 127.0.0.1 6003 
+
+else
+	tail -f raw_audio_pipe | nc -kl 127.0.0.1 6003 
+fi
+
+cleanup

tuner.py

@@ -3,12 +3,11 @@
 ##################################################
 # GNU Radio Python Flow Graph
 # Title: Top Block
-# Generated: Sun May 12 22:10:45 2019
+# Generated: Sat Jun  1 12:54:09 2019
 ##################################################
 
 
 from gnuradio import analog
-from gnuradio import audio
 from gnuradio import blocks
 from gnuradio import eng_notation
 from gnuradio import filter
@@ -21,6 +20,7 @@ import time
 import socket
 import re
 
+
 class top_block(gr.top_block):
 
     def __init__(self):
@@ -29,15 +29,17 @@ class top_block(gr.top_block):
         ##################################################
         # Variables
         ##################################################
-        self.samp_rate = samp_rate = 1536000
+        self.samp_rate = samp_rate = 2.2e6
-        self.frequency = frequency = 96900000
+        self.freq = freq = 101.5e6
+        self.audio_rate = audio_rate = 48000
+        self.audio_interp = audio_interp = 4
 
         ##################################################
         # Blocks
         ##################################################
         self.rtlsdr_source_0 = osmosdr.source( args="numchan=" + str(1) + " " + '' )
         self.rtlsdr_source_0.set_sample_rate(samp_rate)
-        self.rtlsdr_source_0.set_center_freq(frequency, 0)
+        self.rtlsdr_source_0.set_center_freq(freq, 0)
         self.rtlsdr_source_0.set_freq_corr(0, 0)
         self.rtlsdr_source_0.set_dc_offset_mode(2, 0)
         self.rtlsdr_source_0.set_iq_balance_mode(2, 0)
@@ -48,22 +50,25 @@ class top_block(gr.top_block):
         self.rtlsdr_source_0.set_antenna('', 0)
         self.rtlsdr_source_0.set_bandwidth(0, 0)
 
-        self.low_pass_filter_0 = filter.fir_filter_ccf(4, firdes.low_pass(
+        self.rational_resampler_xxx_0 = filter.rational_resampler_ccc(
-        	1, samp_rate, 500000, 60000, firdes.WIN_KAISER, 6.76))
+                interpolation=audio_rate * audio_interp,
-        self.blocks_udp_sink_0 = blocks.udp_sink(gr.sizeof_float*1, '127.0.0.1', 7654, 1472, True)
+                decimation=int(samp_rate),
-        self.blocks_throttle_0 = blocks.throttle(gr.sizeof_gr_complex*1, samp_rate,True)
+                taps=None,
+                fractional_bw=None,
+        )
+        self.blocks_file_sink_0 = blocks.file_sink(gr.sizeof_float*1, 'raw_audio_pipe', False)
+        self.blocks_file_sink_0.set_unbuffered(False)
         self.analog_wfm_rcv_0 = analog.wfm_rcv(
-        	quad_rate=384000,
+        	quad_rate=audio_rate * audio_interp,
-        	audio_decimation=8,
+        	audio_decimation=audio_interp,
         )
 
         ##################################################
         # Connections
         ##################################################
-        self.connect((self.analog_wfm_rcv_0, 0), (self.blocks_udp_sink_0, 0))
+        self.connect((self.analog_wfm_rcv_0, 0), (self.blocks_file_sink_0, 0))
-        self.connect((self.blocks_throttle_0, 0), (self.low_pass_filter_0, 0))
+        self.connect((self.rational_resampler_xxx_0, 0), (self.analog_wfm_rcv_0, 0))
-        self.connect((self.low_pass_filter_0, 0), (self.analog_wfm_rcv_0, 0))
+        self.connect((self.rtlsdr_source_0, 0), (self.rational_resampler_xxx_0, 0))
-        self.connect((self.rtlsdr_source_0, 0), (self.blocks_throttle_0, 0))
 
     def get_samp_rate(self):
         return self.samp_rate
@@ -71,20 +76,64 @@ class top_block(gr.top_block):
     def set_samp_rate(self, samp_rate):
         self.samp_rate = samp_rate
         self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
-        self.low_pass_filter_0.set_taps(firdes.low_pass(1, self.samp_rate, 500000, 60000, firdes.WIN_KAISER, 6.76))
-        self.blocks_throttle_0.set_sample_rate(self.samp_rate)
 
-    def get_frequency(self):
+    def get_freq(self):
-        return self.frequency
+        return self.freq
 
-    def set_frequency(self, frequency):
+    def set_freq(self, freq):
-        self.frequency = frequency
+        self.freq = freq
-        self.rtlsdr_source_0.set_center_freq(self.frequency, 0)
+        self.rtlsdr_source_0.set_center_freq(self.freq, 0)
+
+    def get_audio_rate(self):
+        return self.audio_rate
+
+    def set_audio_rate(self, audio_rate):
+        self.audio_rate = audio_rate
+
+    def get_audio_interp(self):
+        return self.audio_interp
+
+    def set_audio_interp(self, audio_interp):
+        self.audio_interp = audio_interp
+
+def is_valid_frequency(frequency):
+    return frequency >= 87500000 and frequency <= 108000000
+
+def parse_commands(conn, tb, commands):
+    quit = False
+    for command in commands:
+        if command == "":
+            continue
+        elif command[0] == '?': # Query Section
+            if command[1:] == "VER":
+                conn.sendall("Version 0.1\n")
+            elif command[1:] == "FREQ":
+                conn.sendall(str(tb.get_freq()) + '\n')
+            else:
+                print("UNKNOWN COMMAND: ", command)
+        elif command[0] == ':': # Setter Section
+            if command[1:5] == "FREQ":
+                print("FREQUENCY SET")
+                frequency = float(command[6:])
+                if is_valid_frequency(frequency):
+                    tb.set_freq(frequency)
+                else:
+                    print("ERROR: Invalid Frequency ", frequency)
+            elif command[1:] == "QUIT":
+                print("QUITTING")
+                quit = True
+            else:
+                print("UNKNOWN COMMAND: ", command)
+        else:
+            print("UNKNOWN COMMAND", command)
+    # Return state back to application
+    return {'quit': quit}
 
 
 def main(top_block_cls=top_block, options=None):
     tb = top_block_cls()
     tb.start()
+
     HOST = '127.0.0.1' # Loopback Address (Localhost)
     PORT = 65432 # Semi-Random Port that is non-priviledged (> 1023)
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
@@ -103,34 +152,9 @@ def main(top_block_cls=top_block, options=None):
             commands = re.split(";", data)
             if data == "":
                 break
-            for command in commands:
+            state = parse_commands(conn, tb, commands)
-                if command == "":
+            if state['quit']:
-                    continue
-                elif command[0] == '?':
-                    # Query Section
-                    if command[1:] == "VER":
-                        conn.sendall("Version 0.1\n")
-                    elif command[1:] == "FREQ":
-                        conn.sendall(str(tb.get_frequency()) + '\n')
-                    else:
-                        print("UNKNOWN COMMAND: ", command)
-                elif command[0] == ':':
-                    # Setter Section
-                    if command[1:5] == "FREQ":
-                        print("FREQUENCY SET")
-                        frequency = float(command[6:])
-                        if frequency >= 87500000 and frequency <= 108000000:
-                            tb.set_frequency(frequency)
-                        else:
-                            print("ERROR: Invalid Frequency ", frequency)
-                    elif command[1:] == "QUIT":
-                        print("QUITTING")
                 quit = True
-                    else:
-                        print("UNKNOWN COMMAND: ", command)
-                else:
-                    print("UNKNOWN COMMAND", command)
-
         conn.close()
     s.close()