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-rw-r--r--src/dabOutput/edi/Interleaver.cpp114
-rw-r--r--src/dabOutput/edi/Interleaver.h66
2 files changed, 180 insertions, 0 deletions
diff --git a/src/dabOutput/edi/Interleaver.cpp b/src/dabOutput/edi/Interleaver.cpp
new file mode 100644
index 0000000..ab3a5fc
--- /dev/null
+++ b/src/dabOutput/edi/Interleaver.cpp
@@ -0,0 +1,114 @@
+/*
+ Copyright (C) 2016
+ 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"
+
+namespace edi {
+
+void Interleaver::SetLatency(size_t latency_frames)
+{
+ m_latency = latency_frames;
+}
+
+void Interleaver::PushFragments(const std::vector<PFTFragment> &fragments)
+{
+ // Create vectors containing Fcount*latency fragments in total
+ // and store them into the deque
+ if (m_buffer.empty()) {
+ m_buffer.push_back(fragments);
+ }
+ else {
+ auto& last_buffer = m_buffer.back();
+
+ const bool last_buffer_is_complete =
+ (last_buffer.size() >= m_fragment_count * m_latency);
+
+ if (last_buffer_is_complete) {
+ m_buffer.push_back(fragments);
+ }
+ else {
+ std::copy(fragments.begin(), fragments.end(),
+ std::back_inserter(last_buffer));
+ }
+ }
+
+ m_fragment_count = fragments.size();
+}
+
+std::vector<PFTFragment> Interleaver::Interleave()
+{
+ std::vector<PFTFragment> fragments;
+
+ 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;
+ 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();
+ }
+ }
+
+ return fragments;
+}
+
+}
+
+
diff --git a/src/dabOutput/edi/Interleaver.h b/src/dabOutput/edi/Interleaver.h
new file mode 100644
index 0000000..1a2e26d
--- /dev/null
+++ b/src/dabOutput/edi/Interleaver.h
@@ -0,0 +1,66 @@
+/*
+ Copyright (C) 2016
+ 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/>.
+ */
+
+#pragma once
+
+#include "config.h"
+#include <vector>
+#include <deque>
+#include <stdexcept>
+#include <stdint.h>
+#include "Log.h"
+#include "PFT.h"
+
+namespace edi {
+
+class Interleaver {
+ public:
+ /* 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);
+
+ /* Push the fragments for an AF Packet into the interleaver */
+ void PushFragments(const std::vector< PFTFragment > &fragments);
+
+ std::vector< PFTFragment > Interleave(void);
+
+ private:
+ size_t m_latency = 0;
+ size_t m_fragment_count = 0;
+ size_t m_interleave_offset = 0;
+ size_t m_stride = 0;
+ std::deque<std::vector<PFTFragment> > m_buffer;
+};
+
+}
+