Use new zmq message format version 1

3 files changed, 46 insertions, 3 deletions

diff --git a/src/dabplus-enc-alsa-zmq.cpp b/src/dabplus-enc-alsa-zmq.cpp
index caadfc9..699a256 100644
--- a/src/dabplus-enc-alsa-zmq.cpp
+++ b/src/dabplus-enc-alsa-zmq.cpp
@@ -399,7 +399,10 @@ int main(int argc, char *argv[])
     }
 
     int outbuf_size = subchannel_index*120;
-    uint8_t outbuf[20480];
+    uint8_t zmqframebuf[2048];
+    zmq_frame_header_t *zmq_frame_header = (zmq_frame_header_t*)zmqframebuf;
+
+    uint8_t outbuf[2048];
 
     if(outbuf_size % 5 != 0) {
         fprintf(stderr, "(outbuf_size mod 5) = %d\n", outbuf_size % 5);
@@ -585,7 +588,17 @@ int main(int argc, char *argv[])
 
             // ------------ ZeroMQ transmit
             try {
-                zmq_sock.send(outbuf, outbuf_size, ZMQ_DONTWAIT);
+                zmq_frame_header->version = 1;
+                zmq_frame_header->encoder = ZMQ_ENCODER_FDK;
+                zmq_frame_header->datasize = outbuf_size;
+                zmq_frame_header->audiolevel_left = peak_left;
+                zmq_frame_header->audiolevel_right = peak_right;
+
+                memcpy(ZMQ_FRAME_DATA(zmq_frame_header),
+                        outbuf, outbuf_size);
+
+                zmq_sock.send(zmqframebuf, ZMQ_FRAME_SIZE(zmq_frame_header),
+                        ZMQ_DONTWAIT);
             }
             catch (zmq::error_t& e) {
                 fprintf(stderr, "ZeroMQ send error !\n");
diff --git a/src/utils.c b/src/utils.c
index 3b0bee4..a9aefbe 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1,6 +1,7 @@
 #include "utils.h"
 #include <unistd.h>
 #include <stdint.h>
+#include <math.h>
 
 /* Taken from sox */
 const char* level(int channel, int* peak)
diff --git a/src/utils.h b/src/utils.h
index c7ddc1e..aa8dc8a 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -2,6 +2,7 @@
 #define UTILS_H_
 
 #include <math.h>
+#include <stdint.h>
 
 #define MIN(a,b) (((a)<(b))?(a):(b))
 #define MAX(a,b) (((a)>(b))?(a):(b))
@@ -10,8 +11,36 @@
 
 #define linear_to_dB(x) (log10(x) * 20)
 
-
+/* Calculate the little string containing a bargraph
+ * 'VU-meter' from the peak value measured
+ */
 const char* level(int channel, int* peak);
 
+/* This defines the on-wire representation of a ZMQ message header.
+ *
+ * The data follows right after this header */
+struct zmq_frame_header_t
+{
+    uint16_t version; // we support version=1 now
+    uint16_t encoder; // see ZMQ_ENCODER_XYZ
+
+    /* length of the 'data' field */
+    uint32_t datasize;
+
+    /* Audio level, peak, linear PCM */
+    int16_t audiolevel_left;
+    int16_t audiolevel_right;
+
+    /* Data follows this header */
+} __attribute__ ((packed));
+
+#define ZMQ_ENCODER_FDK 1
+
+/* The expected frame size incl data of the given frame */
+#define ZMQ_FRAME_SIZE(f) (sizeof(zmq_frame_header_t) + f->datasize)
+
+#define ZMQ_FRAME_DATA(f) ( ((uint8_t*)f)+sizeof(zmq_frame_header_t) )
+
+
 #endif