dtv: Fix scrambler and BCH encoder for MEDIUM size frames.

DVB-S2X VL-SNR MEDIUM size frames are not divisible by 8.
author: Ron Economos <w6rz@comcast.net> 2019-04-04 01:36:15 -0700
committer: Marcus Müller <marcus@hostalia.de> 2019-04-19 19:09:05 +0200
commit: efac27ca6438a36fadcdaad5164f90b1b423e2b5 (patch)
tree: c200667fc0c0ff1595f70924a4553678ac6821d4 /gr-dtv
parent: 8c80f14fd9e9e74bae46932d8168a1afdd3fd0a2 (diff)
4 files changed, 104 insertions, 32 deletions
diff --git a/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.cc b/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.cc
index c9401258b7..90d5535599 100644
--- a/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.cc
+++ b/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.cc
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /* 
- * Copyright 2015,2016 Free Software Foundation, Inc.
+ * Copyright 2015,2016,2019 Free Software Foundation, Inc.
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -246,6 +246,7 @@ namespace gr {
       }
 
       init_bb_randomiser();
+      frame_size = framesize;
       set_output_multiple(kbch);
     }
 
@@ -268,8 +269,8 @@ namespace gr {
           sr |= 0x4000;
         }
       }
+      bb_randomize32 = (uint32_t*)&bb_randomise[0];
       bb_randomize64 = (uint64_t*)&bb_randomise[0];
-
     }
 
     int
@@ -277,13 +278,23 @@ namespace gr {
                           gr_vector_const_void_star &input_items,
                           gr_vector_void_star &output_items)
     {
-      // noutput_items is multiple of kbch and kbch is always divisible by 8
       const uint64_t *in = (const uint64_t *) input_items[0];
       uint64_t *out = (uint64_t *) output_items[0];
+      const uint32_t *inm = (const uint32_t *) input_items[0];
+      uint32_t *outm = (uint32_t *) output_items[0];
 
-      for (int i = 0; i < noutput_items; i += kbch) {
-        for (int j = 0; j < kbch/8; ++j) {
-          *out++ = *in++ ^ bb_randomize64[j];
+      if (frame_size != FECFRAME_MEDIUM) {
+        for (int i = 0; i < noutput_items; i += kbch) {
+          for (int j = 0; j < kbch / 8; ++j) {
+            *out++ = *in++ ^ bb_randomize64[j];
+          }
+        }
+      }
+      else {
+        for (int i = 0; i < noutput_items; i += kbch) {
+          for (int j = 0; j < kbch / 4; ++j) {
+            *outm++ = *inm++ ^ bb_randomize32[j];
+          }
         }
       }
 
diff --git a/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.h b/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.h
index 062e1b68a2..547cd3544d 100644
--- a/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.h
+++ b/gr-dtv/lib/dvb/dvb_bbscrambler_bb_impl.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /* 
- * Copyright 2015 Free Software Foundation, Inc.
+ * Copyright 2015,2019 Free Software Foundation, Inc.
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -31,7 +31,9 @@ namespace gr {
     {
      private:
       int kbch;
+      int frame_size;
       unsigned char bb_randomise[FRAME_SIZE_NORMAL];
+      uint32_t* bb_randomize32;
       uint64_t* bb_randomize64;
       void init_bb_randomiser(void);
 
diff --git a/gr-dtv/lib/dvb/dvb_bch_bb_impl.cc b/gr-dtv/lib/dvb/dvb_bch_bb_impl.cc
index 6f184c8e05..48c73c3c75 100644
--- a/gr-dtv/lib/dvb/dvb_bch_bb_impl.cc
+++ b/gr-dtv/lib/dvb/dvb_bch_bb_impl.cc
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /* 
- * Copyright 2015,2016,2018 Free Software Foundation, Inc.
+ * Copyright 2015,2016,2018,2019 Free Software Foundation, Inc.
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -390,6 +390,7 @@ namespace gr {
       }
 
       bch_poly_build_tables();
+      frame_size = framesize;
       set_output_multiple(nbch);
     }
 
@@ -455,6 +456,26 @@ namespace gr {
     }
 
     void
+    dvb_bch_bb_impl::calculate_medium_crc_table(void)
+    {
+      for (int divident = 0; divident < 16; divident++) { /* iterate over all possible input byte values 0 - 15 */
+        std::bitset<MAX_BCH_PARITY_BITS> curByte(divident);
+        curByte <<= num_parity_bits - 4;
+
+        for (unsigned char bit = 0; bit < 4; bit++) {
+          if ((curByte[num_parity_bits - 1]) != 0) {
+            curByte <<= 1;
+            curByte ^= polynome;
+          }
+          else {
+            curByte <<= 1;
+          }
+        }
+        crc_medium_table[divident] = curByte;
+      }
+    }
+
+    void
     dvb_bch_bb_impl::bch_poly_build_tables(void)
     {
       // Normal polynomials
@@ -569,6 +590,7 @@ for (unsigned int i = 0; i < num_parity_bits; i ++) {\
         break;
       }
       calculate_crc_table();
+      calculate_medium_crc_table();
     }
 
     int
@@ -585,34 +607,68 @@ for (unsigned int i = 0; i < num_parity_bits; i ++) {\
       std::bitset<MAX_BCH_PARITY_BITS> parity_bits;
       int consumed = 0;
 
-      for (int i = 0; i < noutput_items; i += nbch) {
-        for (int j = 0; j < (int)kbch / 8; j++) {
-          b = 0;
-
-          // calculate the crc using the lookup table, cf. http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html
-          for (int e = 0; e < 8; e++) {
-            temp = *in++;
-            *out++ = temp;
-            consumed++;
-
-            b |= temp << (7 - e);
+      if (frame_size != FECFRAME_MEDIUM) {
+        for (int i = 0; i < noutput_items; i += nbch) {
+          for (int j = 0; j < (int)kbch / 8; j++) {
+            b = 0;
+
+            // calculate the crc using the lookup table, cf. http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html
+            for (int e = 0; e < 8; e++) {
+              temp = *in++;
+              *out++ = temp;
+              consumed++;
+
+              b |= temp << (7 - e);
+            }
+
+            msb = 0;
+            for (int n = 1; n <= 8; n++) {
+              temp = parity_bits[num_parity_bits - n];
+              msb |= temp << (8 - n);
+            }
+            /* XOR-in next input byte into MSB of crc and get this MSB, that's our new intermediate divident */
+            unsigned char pos = (msb ^ b);
+            /* Shift out the MSB used for division per lookuptable and XOR with the remainder */
+            parity_bits = (parity_bits << 8) ^ crc_table[pos];
           }
 
-          msb = 0;
-          for (int n = 1; n <= 8; n++) {
-            temp = parity_bits[num_parity_bits - n];
-            msb |= temp << (8 - n);
+          // Now add the parity bits to the output
+          for (unsigned int n = 0; n < num_parity_bits; n++) {
+            *out++ = (char) parity_bits[num_parity_bits - 1];
+            parity_bits <<= 1;
           }
-          /* XOR-in next input byte into MSB of crc and get this MSB, that's our new intermediate divident */
-          unsigned char pos = (msb ^ b);
-          /* Shift out the MSB used for division per lookuptable and XOR with the remainder */
-          parity_bits = (parity_bits << 8) ^ crc_table[pos];
         }
+      }
+      else {
+        for (int i = 0; i < noutput_items; i += nbch) {
+          for (int j = 0; j < (int)kbch / 4; j++) {
+            b = 0;
+
+            // calculate the crc using the lookup table, cf. http://www.sunshine2k.de/articles/coding/crc/understanding_crc.html
+            for (int e = 0; e < 4; e++) {
+              temp = *in++;
+              *out++ = temp;
+              consumed++;
+
+              b |= temp << (3 - e);
+            }
+
+            msb = 0;
+            for (int n = 1; n <= 4; n++) {
+              temp = parity_bits[num_parity_bits - n];
+              msb |= temp << (4 - n);
+            }
+            /* XOR-in next input byte into MSB of crc and get this MSB, that's our new intermediate divident */
+            unsigned char pos = (msb ^ b);
+            /* Shift out the MSB used for division per lookuptable and XOR with the remainder */
+            parity_bits = (parity_bits << 4) ^ crc_medium_table[pos];
+          }
 
-        // Now add the parity bits to the output
-        for (unsigned int n = 0; n < num_parity_bits; n++) {
-          *out++ = (char) parity_bits[num_parity_bits - 1];
-          parity_bits <<= 1;
+          // Now add the parity bits to the output
+          for (unsigned int n = 0; n < num_parity_bits; n++) {
+            *out++ = (char) parity_bits[num_parity_bits - 1];
+            parity_bits <<= 1;
+          }
         }
       }
 
diff --git a/gr-dtv/lib/dvb/dvb_bch_bb_impl.h b/gr-dtv/lib/dvb/dvb_bch_bb_impl.h
index d715161431..1d7282c892 100644
--- a/gr-dtv/lib/dvb/dvb_bch_bb_impl.h
+++ b/gr-dtv/lib/dvb/dvb_bch_bb_impl.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /* 
- * Copyright 2015,2016 Free Software Foundation, Inc.
+ * Copyright 2015,2016,2019 Free Software Foundation, Inc.
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -36,12 +36,15 @@ namespace gr {
       unsigned int kbch;
       unsigned int nbch;
       unsigned int bch_code;
+      unsigned int frame_size;
 
       std::bitset<MAX_BCH_PARITY_BITS> crc_table[256];
+      std::bitset<MAX_BCH_PARITY_BITS> crc_medium_table[16];
       unsigned int num_parity_bits;
       std::bitset<MAX_BCH_PARITY_BITS> polynome;
 
       void calculate_crc_table();
+      void calculate_medium_crc_table();
       int poly_mult(const int*, int, const int*, int, int*);
       void bch_poly_build_tables(void);
author	Ron Economos <w6rz@comcast.net>	2019-04-04 01:36:15 -0700
committer	Marcus Müller <marcus@hostalia.de>	2019-04-19 19:09:05 +0200
commit	efac27ca6438a36fadcdaad5164f90b1b423e2b5 (patch)
tree	c200667fc0c0ff1595f70924a4553678ac6821d4 /gr-dtv
parent	8c80f14fd9e9e74bae46932d8168a1afdd3fd0a2 (diff)