Add option to pad TAGPacket in different ways

8 files changed, 73 insertions, 14 deletions

diff --git a/doc/example.mux b/doc/example.mux
index 1e6495b..3dd8f17 100644
--- a/doc/example.mux
+++ b/doc/example.mux
@@ -308,6 +308,12 @@ outputs {
 
         ; show more debugging info
         verbose     true
+
+        ; (optional) set the kind of alignment to use in TAG Packets
+        ; 0: no padding
+        ; 8: pad to eight bytes (default)
+        ; above 8: insert *dmy TAG Item to pad to given size in bytes
+        ;tagpacket_alignment 8
     }
 
     ; Other outputs:
diff --git a/src/DabMultiplexer.cpp b/src/DabMultiplexer.cpp
index e79d3fa..ccf3594 100644
--- a/src/DabMultiplexer.cpp
+++ b/src/DabMultiplexer.cpp
@@ -418,7 +418,7 @@ void DabMultiplexer::mux_frame(std::vector<boost::shared_ptr<DabOutput> >& outpu
     map<dabSubchannel*, TagESTn*> edi_subchannelToTag;
 
     // The above Tag Items will be assembled into a TAG Packet
-    TagPacket edi_tagpacket;
+    TagPacket edi_tagpacket(edi_conf.tagpacket_alignment);
 
     edi_tagDETI.atstf = 1;
     edi_tagDETI.utco = 0;
diff --git a/src/DabMux.cpp b/src/DabMux.cpp
index 854c311..04aed2b 100644
--- a/src/DabMux.cpp
+++ b/src/DabMux.cpp
@@ -321,18 +321,20 @@ int main(int argc, char *argv[])
 #if HAVE_OUTPUT_EDI
                 ptree pt_edi = pt_outputs.get_child("edi");
 
-                edi_conf.enabled     = true;
+                edi_conf.enabled             = true;
 
-                edi_conf.dest_addr   = pt_edi.get<string>("destination");
-                edi_conf.dest_port   = pt_edi.get<unsigned int>("port");
-                edi_conf.source_port = pt_edi.get<unsigned int>("sourceport");
+                edi_conf.dest_addr           = pt_edi.get<string>("destination");
+                edi_conf.dest_port           = pt_edi.get<unsigned int>("port");
+                edi_conf.source_port         = pt_edi.get<unsigned int>("sourceport");
 
-                edi_conf.dump        = pt_edi.get<bool>("dump");
-                edi_conf.enable_pft  = pt_edi.get<bool>("enable_pft");
-                edi_conf.verbose     = pt_edi.get<bool>("verbose");
+                edi_conf.dump                = pt_edi.get<bool>("dump");
+                edi_conf.enable_pft          = pt_edi.get<bool>("enable_pft");
+                edi_conf.verbose             = pt_edi.get<bool>("verbose");
 
-                edi_conf.fec         = pt_edi.get<unsigned int>("fec");
-                edi_conf.chunk_len   = pt_edi.get<unsigned int>("chunk_len", 207);
+                edi_conf.fec                 = pt_edi.get<unsigned int>("fec", 3);
+                edi_conf.chunk_len           = pt_edi.get<unsigned int>("chunk_len", 207);
+
+                edi_conf.tagpacket_alignment = pt_edi.get<unsigned int>("tagpacket_alignment", 8);
 
                 mux.set_edi_config(edi_conf);
 #else
diff --git a/src/dabOutput/dabOutput.h b/src/dabOutput/dabOutput.h
index c8ce9f2..cd48790 100644
--- a/src/dabOutput/dabOutput.h
+++ b/src/dabOutput/dabOutput.h
@@ -64,6 +64,7 @@ struct edi_configuration_t {
     bool enable_pft;
     std::string dest_addr;
     unsigned int dest_port;
+    unsigned int tagpacket_alignment;
 };
 
 
diff --git a/src/dabOutput/edi/TagItems.cpp b/src/dabOutput/edi/TagItems.cpp
index 2cae7d1..b97721a 100644
--- a/src/dabOutput/edi/TagItems.cpp
+++ b/src/dabOutput/edi/TagItems.cpp
@@ -171,5 +171,25 @@ std::vector<uint8_t> TagESTn::Assemble()
     */
     return packet;
 }
+
+std::vector<uint8_t> TagStarDMY::Assemble()
+{
+    std::string pack_data("*dmy");
+    std::vector<uint8_t> packet(pack_data.begin(), pack_data.end());
+
+    packet.resize(4 + 4 + length_);
+
+    const uint32_t length_bits = length_ * 8;
+
+    packet[4] = (length_bits >> 24) & 0xFF;
+    packet[5] = (length_bits >> 16) & 0xFF;
+    packet[6] = (length_bits >> 8) & 0xFF;
+    packet[7] = length_bits & 0xFF;
+
+    // The remaining bytes in the packet are "undefined data"
+
+    return packet;
+}
+
 #endif
 
diff --git a/src/dabOutput/edi/TagItems.h b/src/dabOutput/edi/TagItems.h
index fccea2d..e75d241 100644
--- a/src/dabOutput/edi/TagItems.h
+++ b/src/dabOutput/edi/TagItems.h
@@ -111,5 +111,18 @@ class TagESTn : public TagItem
     private:
         uint8_t id_;
 };
+
+// ETSI TS 102 821, 5.2.2.2 Dummy padding
+class TagStarDMY : public TagItem
+{
+    public:
+        /* length is the TAG value length in bytes */
+        TagStarDMY(uint32_t length) : length_(length) {}
+        std::vector<uint8_t> Assemble();
+
+    private:
+        uint32_t length_;
+};
+
 #endif
 
diff --git a/src/dabOutput/edi/TagPacket.cpp b/src/dabOutput/edi/TagPacket.cpp
index aa4f23b..435c071 100644
--- a/src/dabOutput/edi/TagPacket.cpp
+++ b/src/dabOutput/edi/TagPacket.cpp
@@ -33,6 +33,8 @@
 #include <stdint.h>
 #include <cassert>
 
+TagPacket::TagPacket(unsigned int alignment) : m_alignment(alignment)
+{ }
 
 std::vector<uint8_t> TagPacket::Assemble()
 {
@@ -49,10 +51,21 @@ std::vector<uint8_t> TagPacket::Assemble()
         //std::cerr << "     Add TAGItem of length " << tag_data.size() << std::endl;
     }
 
-    // Add padding
-    while (packet.size() % 8 > 0)
-    {
-        packet.push_back(0); // TS 102 821, 5.1, "padding shall be undefined"
+    if (m_alignment == 0) { /* no padding */ }
+    else if (m_alignment == 8) {
+        // Add padding inside TAG packet
+        while (packet.size() % 8 > 0) {
+            packet.push_back(0); // TS 102 821, 5.1, "padding shall be undefined"
+        }
+    }
+    else if (m_alignment > 8) {
+        TagStarDMY dmy(m_alignment - 8);
+        auto dmy_data = dmy.Assemble();
+        packet.insert(packet.end(), dmy_data.begin(), dmy_data.end());
+    }
+    else {
+        std::cerr << "Invalid alignment requirement " << m_alignment <<
+            " defined in TagPacket" << std::endl;
     }
 
     return packet;
diff --git a/src/dabOutput/edi/TagPacket.h b/src/dabOutput/edi/TagPacket.h
index 9d69226..5ad1904 100644
--- a/src/dabOutput/edi/TagPacket.h
+++ b/src/dabOutput/edi/TagPacket.h
@@ -42,9 +42,13 @@
 class TagPacket
 {
     public:
+        TagPacket(unsigned int alignment);
         std::vector<uint8_t> Assemble();
 
         std::list<TagItem*> tag_items;
+
+    private:
+        unsigned int m_alignment;
 };
 
 #endif