From 4cd23cf44572af7f2c07d03f2e5d5b16f1a86def Mon Sep 17 00:00:00 2001
From: Jakob Ketterl <jakob.ketterl@gmx.de>
Date: Tue, 7 May 2019 20:06:06 +0200
Subject: [PATCH] more work to allow seamless config switching

---
 config_webrx.py     |  4 +++-
 csdr.py             | 13 +++++++++----
 htdocs/openwebrx.js |  4 ++--
 owrx/controllers.py |  2 +-
 owrx/source.py      | 10 +++++-----
 5 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/config_webrx.py b/config_webrx.py
index a9c25d1..ca91905 100644
--- a/config_webrx.py
+++ b/config_webrx.py
@@ -159,7 +159,9 @@ To use a HackRF, compile the HackRF host tools from its "stdout" branch:
 
 # ==== Misc settings ====
 
-shown_center_freq = center_freq #you can change this if you use an upconverter
+# you can change this if you use an upconverter. formula is:
+# shown_center_freq = center_freq + lfo_offset
+lfo_offset = 0
 
 client_audio_buffer_size = 5
 #increasing client_audio_buffer_size will:
diff --git a/csdr.py b/csdr.py
index 1807fe0..2a27228 100755
--- a/csdr.py
+++ b/csdr.py
@@ -211,8 +211,11 @@ class dsp:
         if self.fft_compression=="adpcm": return (self.secondary_fft_size/2)+(10/2)
 
     def set_samp_rate(self,samp_rate):
-        #to change this, restart is required
         self.samp_rate=samp_rate
+        self.calculate_decimation()
+        if self.running: self.restart()
+
+    def calculate_decimation(self):
         self.decimation=1
         while self.samp_rate/(self.decimation+1)>self.output_rate:
             self.decimation+=1
@@ -229,7 +232,7 @@ class dsp:
 
     def set_output_rate(self,output_rate):
         self.output_rate=output_rate
-        self.set_samp_rate(self.samp_rate) #as it depends on output_rate
+        self.calculate_decimation()
 
     def set_demodulator(self,demodulator):
         #to change this, restart is required
@@ -314,6 +317,9 @@ class dsp:
                 except Exception as e: print("[openwebrx-dsp-plugin:csdr] try_delete_pipes() ::", e)
 
     def start(self):
+        if (self.running): return
+        self.running = True
+
         command_base=self.chain(self.demodulator)
 
         #create control pipes for csdr
@@ -363,8 +369,6 @@ class dsp:
 
         threading.Thread(target = watch_thread).start()
 
-        self.running = True
-
         #open control pipes for csdr and send initialization data
         if self.bpf_pipe != None:
             self.bpf_pipe_file=open(self.bpf_pipe,"w")
@@ -422,6 +426,7 @@ class dsp:
             # except: print "[openwebrx-dsp-plugin:csdr] stop() :: unlink failed: " + self.iqtee2_pipe
 
     def restart(self):
+        if not self.running: return
         self.stop()
         self.start()
 
diff --git a/htdocs/openwebrx.js b/htdocs/openwebrx.js
index 230d1e4..a5c6ee5 100644
--- a/htdocs/openwebrx.js
+++ b/htdocs/openwebrx.js
@@ -1172,7 +1172,7 @@ function on_ws_recv(evt)
                         window.starting_offset_frequency = config.start_offset_frequency;
                         window.audio_buffering_fill_to = config.client_audio_buffer_size;
                         bandwidth = config.samp_rate;
-                        center_freq = config.shown_center_freq;
+                        center_freq = config.center_freq + config.lfo_offset;
                         fft_size = config.fft_size;
 						fft_fps = config.fft_fps;
 						audio_compression = config.audio_compression;
@@ -1183,7 +1183,7 @@ function on_ws_recv(evt)
 						waterfall_init();
 						audio_preinit();
 
-						if (audio_allowed) audio_init();
+						if (audio_allowed && !audio_initialized) audio_init();
 						waterfall_clear();
                     break;
                     case "secondary_config":
diff --git a/owrx/controllers.py b/owrx/controllers.py
index 67868a2..10bda5c 100644
--- a/owrx/controllers.py
+++ b/owrx/controllers.py
@@ -85,7 +85,7 @@ class WebSocketMessageHandler(object):
             self.client = OpenWebRxClient(conn)
 
             config_keys = ["waterfall_colors", "waterfall_min_level", "waterfall_max_level",
-                           "waterfall_auto_level_margin", "shown_center_freq", "samp_rate", "fft_size", "fft_fps",
+                           "waterfall_auto_level_margin", "lfo_offset", "samp_rate", "fft_size", "fft_fps",
                            "audio_compression", "fft_compression", "max_clients", "start_mod",
                            "client_audio_buffer_size", "start_freq", "center_freq"]
 
diff --git a/owrx/source.py b/owrx/source.py
index 832cd1e..d889700 100644
--- a/owrx/source.py
+++ b/owrx/source.py
@@ -34,17 +34,17 @@ class RtlNmuxSource(object):
             self.start()
         props.wire(restart)
 
-        featureDetector = FeatureDetector()
-        if not featureDetector.is_available(props["rtl_type"]):
-            print("The RTL source type {0} is not available. please check requirements.".format(props["rtl_type"]))
-            return
-
         self.start()
 
     def start(self):
 
         props = self.props
 
+        featureDetector = FeatureDetector()
+        if not featureDetector.is_available(props["rtl_type"]):
+            print("The RTL source type {0} is not available. please check requirements.".format(props["rtl_type"]))
+            return
+
         params = RtlNmuxSource.types[props["rtl_type"]]
 
         start_sdr_command = params["command"].format(