1 files changed, 98 insertions, 0 deletions
diff --git a/src/watermarkdecoder.hpp b/src/watermarkdecoder.hpp
new file mode 100644
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--- /dev/null
+++ b/src/watermarkdecoder.hpp
@@ -0,0 +1,98 @@
+/*
+    Copyright (C) 2014 CSP Innovazione nelle ICT s.c.a r.l. (http://www.csp.it/)
+    Copyright (C) 2016 Matthias P. Braendli (http://www.opendigitalradio.org)
+    Copyright (C) 2015 Data Path
+
+    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/>.
+
+    Authors:
+         Sergio Sagliocco <sergio.sagliocco@csp.it>
+         Matthias P. Braendli <matthias@mpb.li>
+                   / |  |-  ')|)  |-|_ _ (|,_   .|  _  ,_ \
+         Data Path \(|(||_(|/_| (||_||(a)_||||(|||.(_()|||/
+
+*/
+
+#pragma once
+#include <vector>
+#include <sstream>
+#include "utils.hpp"
+
+class WatermarkDecoder
+{
+    public:
+        WatermarkDecoder() {}
+
+        void push_confind_bit(bool confind)
+        {
+            // The ConfInd of FIG 0/10 contains the CRC-DABMUX and ODR-DabMux watermark
+            m_confind_bits.push_back(confind);
+        }
+
+        std::string calculate_watermark()
+        {
+            // First try to find the 0x55 0x55 sync in the waternark data
+            size_t bit_ix;
+            int alternance_count = 0;
+            bool last_bit = 1;
+            for (bit_ix = 0; bit_ix < m_confind_bits.size(); bit_ix++) {
+                if (alternance_count == 16) {
+                    break;
+                }
+                else {
+                    if (last_bit != m_confind_bits[bit_ix]) {
+                        last_bit = m_confind_bits[bit_ix];
+                        alternance_count++;
+                    }
+                    else {
+                        alternance_count = 0;
+                        last_bit = 1;
+                    }
+                }
+
+            }
+
+            printf("Found SYNC at offset %zu out of %zu\n", bit_ix - alternance_count, m_confind_bits.size());
+
+            std::stringstream watermark_ss;
+
+            uint8_t b = 0;
+            size_t i = 0;
+            while (bit_ix < m_confind_bits.size()) {
+
+                b |= m_confind_bits[bit_ix] << (7 - i);
+
+                if (i == 7) {
+                    watermark_ss << (char)b;
+
+                    b = 0;
+                    i = 0;
+                }
+                else {
+                    i++;
+                }
+
+                bit_ix += 2;
+            }
+
+            return watermark_ss.str();
+        }
+
+    private:
+        const WatermarkDecoder& operator=(const WatermarkDecoder&) = delete;
+        WatermarkDecoder(const WatermarkDecoder&) = delete;
+
+        std::vector<bool> m_confind_bits;
+};
+