Common fc2902b and 4ad00b8: Update EDI output interleaver and spreading

5 files changed, 100 insertions, 250 deletions

diff --git a/lib/edioutput/EDIConfig.h b/lib/edioutput/EDIConfig.h
index 647d77e..be6c9c4 100644
--- a/lib/edioutput/EDIConfig.h
+++ b/lib/edioutput/EDIConfig.h
@@ -71,10 +71,11 @@ struct configuration_t {
     bool enable_pft    = false;      // Enable protection and fragmentation
     unsigned int tagpacket_alignment = 0;
     std::vector<std::shared_ptr<destination_t> > destinations;
-    unsigned int latency_frames = 0; // if nonzero, enable interleaver with a latency of latency_frames * 24ms
+    double fragment_spreading_factor = 0.95;
+    // Spread transmission of fragments in time. 1.0 = 100% means spreading over the whole duration of a frame (24ms)
+    // Above 100% means that the fragments are spread over several 24ms periods, interleaving the AF packets.
 
     bool enabled() const { return destinations.size() > 0; }
-    bool interleaver_enabled() const { return latency_frames > 0; }
 
     void print() const;
 };
diff --git a/lib/edioutput/Interleaver.cpp b/lib/edioutput/Interleaver.cpp
deleted file mode 100644
index f26a50e..0000000
--- a/lib/edioutput/Interleaver.cpp
+++ /dev/null
@@ -1,122 +0,0 @@
-/*
-   Copyright (C) 2017
-   Matthias P. Braendli, matthias.braendli@mpb.li
-
-    http://www.opendigitalradio.org
-
-   EDI output,
-   Interleaving of PFT fragments to increase robustness against
-   burst packet loss.
-
-   This is possible because EDI has to assume that fragments may reach
-   the receiver out of order.
-
-   */
-/*
-   This file is part of ODR-DabMux.
-
-   ODR-DabMux is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as
-   published by the Free Software Foundation, either version 3 of the
-   License, or (at your option) any later version.
-
-   ODR-DabMux is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with ODR-DabMux.  If not, see <http://www.gnu.org/licenses/>.
-   */
-
-#include "Interleaver.h"
-#include <cassert>
-
-namespace edi {
-
-void Interleaver::SetLatency(size_t latency_frames)
-{
-    m_latency = latency_frames;
-}
-
-Interleaver::fragment_vec Interleaver::Interleave(fragment_vec &fragments)
-{
-    m_fragment_count = fragments.size();
-
-    // Create vectors containing Fcount*latency fragments in total
-    // and store them into the deque
-    if (m_buffer.empty()) {
-        m_buffer.emplace_back();
-    }
-
-    auto& last_buffer = m_buffer.back();
-
-    for (auto& fragment : fragments) {
-        const bool last_buffer_is_complete =
-                (last_buffer.size() >= m_fragment_count * m_latency);
-
-        if (last_buffer_is_complete) {
-            m_buffer.emplace_back();
-            last_buffer = m_buffer.back();
-        }
-
-        last_buffer.push_back(std::move(fragment));
-    }
-
-    fragments.clear();
-
-    while ( not m_buffer.empty() and
-            (m_buffer.front().size() >= m_fragment_count * m_latency)) {
-
-        auto& first_buffer = m_buffer.front();
-
-        assert(first_buffer.size() == m_fragment_count * m_latency);
-
-        /* Assume we have 5 fragments per AF frame, and latency of 3.
-         * This will give the following strides:
-         *    0        1     2
-         * +-------+-------+---+
-         * | 0   1 | 2   3 | 4 |
-         * |       |   +---+   |
-         * | 5   6 | 7 | 8   9 |
-         * |   +---+   |       |
-         * |10 |11  12 |13  14 |
-         * +---+-------+-------+
-         *
-         * ix will be 0, 5, 10, 1, 6 in the first loop
-         */
-
-        for (size_t i = 0; i < m_fragment_count; i++) {
-            const size_t ix = m_interleave_offset + m_fragment_count * m_stride;
-            m_interleaved_fragments.push_back(first_buffer.at(ix));
-
-            m_stride += 1;
-            if (m_stride >= m_latency) {
-                m_interleave_offset++;
-                m_stride = 0;
-            }
-        }
-
-        if (m_interleave_offset >= m_fragment_count) {
-            m_interleave_offset = 0;
-            m_stride = 0;
-            m_buffer.pop_front();
-        }
-    }
-
-    std::vector<PFTFragment> interleaved_frags;
-
-    const size_t n = std::min(m_fragment_count, m_interleaved_fragments.size());
-    std::move(m_interleaved_fragments.begin(),
-              m_interleaved_fragments.begin() + n,
-              std::back_inserter(interleaved_frags));
-    m_interleaved_fragments.erase(
-              m_interleaved_fragments.begin(),
-              m_interleaved_fragments.begin() + n);
-
-    return interleaved_frags;
-}
-
-}
-
-
diff --git a/lib/edioutput/Interleaver.h b/lib/edioutput/Interleaver.h
deleted file mode 100644
index 3029d5d..0000000
--- a/lib/edioutput/Interleaver.h
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
-   Copyright (C) 2017
-   Matthias P. Braendli, matthias.braendli@mpb.li
-
-    http://www.opendigitalradio.org
-
-   EDI output,
-   Interleaving of PFT fragments to increase robustness against
-   burst packet loss.
-
-   This is possible because EDI has to assume that fragments may reach
-   the receiver out of order.
-
-   */
-/*
-   This file is part of the ODR-mmbTools.
-
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as
-   published by the Free Software Foundation, either version 3 of the
-   License, or (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#pragma once
-
-#include "config.h"
-#include <vector>
-#include <deque>
-#include <stdexcept>
-#include <cstdint>
-#include "Log.h"
-#include "PFT.h"
-
-namespace edi {
-
-class Interleaver {
-    public:
-        using fragment_vec = std::vector<PFTFragment>;
-
-        /* Configure the interleaver to use latency_frames number of AF
-         * packets for interleaving. Total delay through the interleaver
-         * will be latency_frames * 24ms
-         */
-        void SetLatency(size_t latency_frames);
-
-        /* Move the fragments for an AF Packet into the interleaver and
-         * return interleaved fragments to be transmitted.
-         */
-        fragment_vec Interleave(fragment_vec &fragments);
-
-    private:
-        size_t m_latency = 0;
-        size_t m_fragment_count = 0;
-        size_t m_interleave_offset = 0;
-        size_t m_stride = 0;
-
-        /* Buffer that accumulates enough fragments to interleave */
-        std::deque<fragment_vec> m_buffer;
-
-        /* Buffer that contains fragments that have been interleaved,
-         * to avoid that the interleaver output is too bursty
-         */
-        std::deque<PFTFragment> m_interleaved_fragments;
-};
-
-}
-
diff --git a/lib/edioutput/Transport.cpp b/lib/edioutput/Transport.cpp
index f8e5dc7..136c71c 100644
--- a/lib/edioutput/Transport.cpp
+++ b/lib/edioutput/Transport.cpp
@@ -27,6 +27,7 @@
 #include "Transport.h"
 #include <iterator>
 #include <cmath>
+#include <thread>
 
 using namespace std;
 
@@ -57,9 +58,6 @@ void configuration_t::print() const
             throw logic_error("EDI destination not implemented");
         }
     }
-    if (interleaver_enabled()) {
-        etiLog.level(info) << " interleave     " << latency_frames * 24 << " ms";
-    }
 }
 
 
@@ -96,19 +94,33 @@ Sender::Sender(const configuration_t& conf) :
         }
     }
 
-    if (m_conf.interleaver_enabled()) {
-        edi_interleaver.SetLatency(m_conf.latency_frames);
-    }
-
     if (m_conf.dump) {
         edi_debug_file.open("./edi.debug");
     }
 
+    if (m_conf.enable_pft) {
+        unique_lock<mutex> lock(m_mutex);
+        m_running = true;
+        m_thread = thread(&Sender::run, this);
+    }
+
     if (m_conf.verbose) {
         etiLog.log(info, "EDI output set up");
     }
 }
 
+Sender::~Sender()
+{
+    {
+        unique_lock<mutex> lock(m_mutex);
+        m_running = false;
+    }
+
+    if (m_thread.joinable()) {
+        m_thread.join();
+    }
+}
+
 void Sender::write(const TagPacket& tagpacket)
 {
     // Assemble into one AF Packet
@@ -119,57 +131,34 @@ void Sender::write(const TagPacket& tagpacket)
         vector<edi::PFTFragment> edi_fragments = edi_pft.Assemble(af_packet);
 
         if (m_conf.verbose) {
-            fprintf(stderr, "EDI Output: Number of PFT fragment before interleaver %zu\n",
-                    edi_fragments.size());
-        }
-
-        if (m_conf.interleaver_enabled()) {
-            edi_fragments = edi_interleaver.Interleave(edi_fragments);
-        }
-
-        if (m_conf.verbose) {
             fprintf(stderr, "EDI Output: Number of PFT fragments %zu\n",
                     edi_fragments.size());
         }
 
         /* Spread out the transmission of all fragments over 25% of the 24ms AF packet duration
-         * to reduce the risk of losing a burst of fragments because of congestion.
-         *
-         * 25% was chosen so that other outputs still have time to do their thing. */
-        auto inter_fragment_wait_time = std::chrono::microseconds(0);
+         * to reduce the risk of losing a burst of fragments because of congestion. */
+        using namespace std::chrono;
+        auto inter_fragment_wait_time = microseconds(0);
         if (edi_fragments.size() > 1) {
-            inter_fragment_wait_time = std::chrono::microseconds(llrint(0.25 * 24000.0 / edi_fragments.size()));
+            inter_fragment_wait_time = microseconds(
+                    llrint(m_conf.fragment_spreading_factor * 24000.0 / edi_fragments.size())
+                    );
         }
 
-        // Send over ethernet
-        for (auto& edi_frag : edi_fragments) {
-            if (m_conf.dump) {
-                ostream_iterator<uint8_t> debug_iterator(edi_debug_file);
-                copy(edi_frag.begin(), edi_frag.end(), debug_iterator);
+        /* Separate insertion into map and transmission so as to make spreading possible */
+        const auto now = steady_clock::now();
+        {
+            auto tp = now;
+            unique_lock<mutex> lock(m_mutex);
+            for (auto& edi_frag : edi_fragments) {
+                m_pending_frames[tp] = move(edi_frag);
+                tp += inter_fragment_wait_time;
             }
-
-            for (auto& dest : m_conf.destinations) {
-                if (const auto& udp_dest = dynamic_pointer_cast<edi::udp_destination_t>(dest)) {
-                    Socket::InetAddress addr;
-                    addr.resolveUdpDestination(udp_dest->dest_addr, udp_dest->dest_port);
-
-                    udp_sockets.at(udp_dest.get())->send(edi_frag, addr);
-                }
-                else if (auto tcp_dest = dynamic_pointer_cast<edi::tcp_server_t>(dest)) {
-                    tcp_dispatchers.at(tcp_dest.get())->write(edi_frag);
-                }
-                else if (auto tcp_dest = dynamic_pointer_cast<edi::tcp_client_t>(dest)) {
-                    tcp_senders.at(tcp_dest.get())->sendall(edi_frag);
-                }
-                else {
-                    throw logic_error("EDI destination not implemented");
-                }
-            }
-
-            std::this_thread::sleep_for(inter_fragment_wait_time);
         }
+
+        // Transmission done in run() function
     }
-    else {
+    else /* PFT disabled */ {
         // Send over ethernet
         if (m_conf.dump) {
             ostream_iterator<uint8_t> debug_iterator(edi_debug_file);
@@ -202,4 +191,49 @@ void Sender::write(const TagPacket& tagpacket)
     }
 }
 
+void Sender::run()
+{
+    while (m_running) {
+        unique_lock<mutex> lock(m_mutex);
+        const auto now = chrono::steady_clock::now();
+
+        // Send over ethernet
+        for (auto it = m_pending_frames.begin(); it != m_pending_frames.end(); ) {
+            const auto& edi_frag = it->second;
+
+            if (it->first <= now) {
+                if (m_conf.dump) {
+                    ostream_iterator<uint8_t> debug_iterator(edi_debug_file);
+                    copy(edi_frag.begin(), edi_frag.end(), debug_iterator);
+                }
+
+                for (auto& dest : m_conf.destinations) {
+                    if (const auto& udp_dest = dynamic_pointer_cast<edi::udp_destination_t>(dest)) {
+                        Socket::InetAddress addr;
+                        addr.resolveUdpDestination(udp_dest->dest_addr, udp_dest->dest_port);
+
+                        udp_sockets.at(udp_dest.get())->send(edi_frag, addr);
+                    }
+                    else if (auto tcp_dest = dynamic_pointer_cast<edi::tcp_server_t>(dest)) {
+                        tcp_dispatchers.at(tcp_dest.get())->write(edi_frag);
+                    }
+                    else if (auto tcp_dest = dynamic_pointer_cast<edi::tcp_client_t>(dest)) {
+                        tcp_senders.at(tcp_dest.get())->sendall(edi_frag);
+                    }
+                    else {
+                        throw logic_error("EDI destination not implemented");
+                    }
+                }
+                it = m_pending_frames.erase(it);
+            }
+            else {
+                ++it;
+            }
+        }
+
+        lock.unlock();
+        this_thread::sleep_for(chrono::microseconds(500));
+    }
+}
+
 }
diff --git a/lib/edioutput/Transport.h b/lib/edioutput/Transport.h
index 56ded3b..3bcc2f4 100644
--- a/lib/edioutput/Transport.h
+++ b/lib/edioutput/Transport.h
@@ -31,13 +31,16 @@
 #include "EDIConfig.h"
 #include "AFPacket.h"
 #include "PFT.h"
-#include "Interleaver.h"
 #include "Socket.h"
 #include <vector>
+#include <chrono>
+#include <map>
 #include <unordered_map>
 #include <stdexcept>
 #include <fstream>
 #include <cstdint>
+#include <thread>
+#include <mutex>
 
 namespace edi {
 
@@ -46,10 +49,15 @@ namespace edi {
 class Sender {
     public:
         Sender(const configuration_t& conf);
+        Sender(const Sender&) = delete;
+        Sender operator=(const Sender&) = delete;
+        ~Sender();
 
         void write(const TagPacket& tagpacket);
 
     private:
+        void run();
+
         bool m_udp_fragmentation_warning_printed = false;
 
         configuration_t m_conf;
@@ -61,12 +69,16 @@ class Sender {
         // The AF Packet will be protected with reed-solomon and split in fragments
         edi::PFT edi_pft;
 
-        // To mitigate for burst packet loss, PFT fragments can be sent out-of-order
-        edi::Interleaver edi_interleaver;
-
         std::unordered_map<udp_destination_t*, std::shared_ptr<Socket::UDPSocket>> udp_sockets;
         std::unordered_map<tcp_server_t*, std::shared_ptr<Socket::TCPDataDispatcher>> tcp_dispatchers;
         std::unordered_map<tcp_client_t*, std::shared_ptr<Socket::TCPSendClient>> tcp_senders;
+
+        // PFT spreading requires sending UDP packets at specific time, independently of
+        // time when write() gets called
+        std::thread m_thread;
+        std::mutex m_mutex;
+        bool m_running = false;
+        std::map<std::chrono::steady_clock::time_point, edi::PFTFragment> m_pending_frames;
 };
 
 }