Fix UDP streaming on MacOS, it was broken due to large UDP packets being truncated

README.md

@@ -200,6 +200,7 @@ The following people and organisations have contributed to gqrx:
 * Dominic Chen
 * Doron Behar
 * Doug Hammond
+* Edouard Lafargue
 * Elias Önal
 * Federico Fuga
 * Frank Brickle, AB2KT

resources/news.txt

@@ -5,6 +5,7 @@
        NEW: Airspy support in Windows binary release.
   IMPROVED: Updated GNU Radio, SDR driver, and Qt versions in AppImage release.
      FIXED: Respond correctly to pipelined remote control commands.
+     FIXED: Limit UDP packet size to 1024, for compatibility with netcat.
    REMOVED: FreeSRP support in AppImage release.
 
 

src/CMakeLists.txt

@@ -12,7 +12,6 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
     else()
         add_subdirectory(osxaudio)
     endif()
-    add_definitions(-DGQRX_OS_MACX)
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux|FreeBSD")
     if(${LINUX_AUDIO_BACKEND} MATCHES "Pulseaudio")
         add_subdirectory(pulseaudio)

src/interfaces/udp_sink_f.cpp

@@ -51,6 +51,12 @@ static const int MAX_IN = 2;  /*!< Maximum number of input streams. */
 static const int MIN_OUT = 0; /*!< Minimum number of output streams. */
 static const int MAX_OUT = 0; /*!< Maximum number of output streams. */
 
+// nc is used widely for receiving UDP streams and some versions of nc,
+// notably on MacOS, use a 1024 byte buffer so we need to make sure we
+// don't send packets that are larger than that, otherwise data will be
+// lost.
+static const int PAYLOAD_SIZE = 1024;
+
 udp_sink_f::udp_sink_f()
     : gr::hier_block2("udp_sink_f",
                       gr::io_signature::make(MIN_IN, MAX_IN, sizeof(float)),
@@ -59,13 +65,7 @@ udp_sink_f::udp_sink_f()
 
     d_f2s = gr::blocks::float_to_short::make(1, 32767);
 #if GNURADIO_VERSION < 0x031000
-#ifdef GQRX_OS_MACX
-    // There seems to be excessive packet loss (even to localhost) on OS X
-    // unless the buffer size is limited.
-    d_sink = gr::blocks::udp_sink::make(sizeof(short), "localhost", 7355, 512);
-#else
-    d_sink = gr::blocks::udp_sink::make(sizeof(short), "localhost", 7355);
-#endif
+    d_sink = gr::blocks::udp_sink::make(sizeof(short), "localhost", 7355, PAYLOAD_SIZE);
     d_sink->disconnect();
 #endif
 
@@ -96,7 +96,7 @@ void udp_sink_f::start_streaming(const std::string host, int port, bool stereo)
     std::cout << (stereo ? "Stereo" : "Mono") << std::endl;
 
 #if GNURADIO_VERSION >= 0x031000
-    d_sink = gr::network::udp_sink::make(sizeof(short), 1, host, port, HEADERTYPE_NONE, 1448, true);
+    d_sink = gr::network::udp_sink::make(sizeof(short), 1, host, port, HEADERTYPE_NONE, PAYLOAD_SIZE, true);
 #endif
 
     if (stereo)