errors to range of bits in codec frame, new burst error model

git-svn-id: https://svn.code.sf.net/p/freetel/code@1160 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/src/c2dec.c b/codec2-dev/src/c2dec.c
index fd4a04d31fcb8975e9855af57d87a6bb953d2577..8b2f2eb67a047f2da756d820cbb8447fe1e50419 100644 (file)
--- a/codec2-dev/src/c2dec.c
+++ b/codec2-dev/src/c2dec.c
@@ -27,14 +27,16 @@
 
 #include "codec2.h"
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 
-#define NONE      0  /* no bit errors         */
-#define UNIFORM   1  /* random bit errors     */
-#define TWO_STATE 2  /* Two state error model */
+#define NONE          0  /* no bit errors                          */
+#define UNIFORM       1  /* random bit errors                      */
+#define TWO_STATE     2  /* Two state error model                  */
+#define UNIFORM_RANGE 3  /* random bit errors over a certain range */
 
 int main(int argc, char *argv[])
 {
@@ -45,13 +47,15 @@ int main(int argc, char *argv[])
     short         *buf;
     unsigned char *bits;
     int            nsam, nbit, nbyte, i, byte, frames, bit_errors, error_mode;
+    int            nstart_bit, nend_bit, bit_rate;
     int            state, next_state;
-    float          ber, r, pstate0, pstate1;
+    float          ber, r, burst_length, burst_period, burst_timer;
 
     if (argc < 4) {
-       printf("basic usage...............: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile\n");
-       printf("uniform errors usage.......: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile uniformBER\n");
-       printf("two state fading usage....: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile probGood probBad\n");
+       printf("basic usage.................: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile\n");
+       printf("uniform errors usage........: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile uniformBER startBit endBit\n");
+       printf("uniform error on range usage: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile uniformBER\n");
+       printf("two state fading usage......: c2dec 3200|2400|1400|1200 InputBitFile OutputRawSpeechFile burstLength burstPeriod\n");
        printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw\n");
        printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw 0.9\n");
        printf("e.g    c2dec 1400 hts1a.c2 hts1a_1400.raw 0.99 0.9\n");
@@ -70,7 +74,8 @@ int main(int argc, char *argv[])
        fprintf(stderr, "Error in mode: %s.  Must be 4800, 3200, 2400, 1400 or 1200\n", argv[1]);
        exit(1);
     }
-    
+    bit_rate = atoi(argv[1]);
+
     if (strcmp(argv[2], "-")  == 0) fin = stdin;
     else if ( (fin = fopen(argv[2],"rb")) == NULL ) {
        fprintf(stderr, "Error opening input bit file: %s: %s.\n",
@@ -87,7 +92,18 @@ int main(int argc, char *argv[])
 
     error_mode = NONE;
     ber = 0.0;
-    pstate0 = pstate1 = 0.0;
+    burst_length = burst_period = 0.0;
+    burst_timer = 0.0;
+
+    codec2 = codec2_create(mode);
+    nsam = codec2_samples_per_frame(codec2);
+    nbit = codec2_bits_per_frame(codec2);
+    buf = (short*)malloc(nsam*sizeof(short));
+    nbyte = (nbit + 7) / 8;
+    bits = (unsigned char*)malloc(nbyte*sizeof(char));
+    frames = bit_errors = 0;
+    nstart_bit = 0;
+    nend_bit = nbit-1;
 
     if (argc == 5) {
         error_mode = UNIFORM;
@@ -96,42 +112,52 @@ int main(int argc, char *argv[])
 
     if (argc == 6) {
         error_mode = TWO_STATE;
-       pstate0 = atof(argv[4]);
-       pstate1 = atof(argv[5]);
+       burst_length = atof(argv[4]);
+       burst_period = atof(argv[5]);
+       nstart_bit = 0;
+       nend_bit = 2;
         state = 0;
     }
 
-    codec2 = codec2_create(mode);
-    nsam = codec2_samples_per_frame(codec2);
-    nbit = codec2_bits_per_frame(codec2);
-    buf = (short*)malloc(nsam*sizeof(short));
-    nbyte = (nbit + 7) / 8;
-    bits = (unsigned char*)malloc(nbyte*sizeof(char));
-    frames = bit_errors = 0;
+    if (argc == 7) {
+        error_mode = UNIFORM_RANGE;
+       ber = atof(argv[4]);
+       nstart_bit = atoi(argv[5]);
+       nend_bit = atoi(argv[6]);
+        fprintf(stderr, "ber: %f nstart_bit: %d nend_bit: %d\n", ber, nstart_bit, nend_bit);
+        state = 0;
+    }
+
+    assert(nend_bit <= nbit);
 
     while(fread(bits, sizeof(char), nbyte, fin) == (size_t)nbyte) {
        frames++;
-       if (error_mode == UNIFORM) {
-           for(i=0; i<nbit; i++) {
+
+        // apply bit errors, MSB of byte 0 is bit 0 in frame */
+        
+       if ((error_mode == UNIFORM) || (error_mode == UNIFORM_RANGE)) {
+           for(i=nstart_bit; i<nend_bit+1; i++) {
                r = (float)rand()/RAND_MAX;
                if (r < ber) {
                    byte = i/8;
                    //printf("nbyte %d nbit %d i %d byte %d\n", nbyte, nbit, i, byte);
-                   bits[byte] ^= 1 << (i - byte*8);
+                   bits[byte] ^= 1 << (7 - i - byte*8);
                    bit_errors++;
                }
            }
        }
 
        if (error_mode == TWO_STATE) {
+            burst_timer += (float)nbit/bit_rate;
+            fprintf(stderr, "burst_timer: %f  state: %d\n", burst_timer, state);
+
             next_state = state;
             switch(state) {
             case 0:
 
                 /* clear channel state - no bit errors */
 
-               r = (float)rand()/RAND_MAX;
-                if (r > pstate0)
+                if (burst_timer > (burst_period - burst_length))
                     next_state = 1;
                 break;
 
@@ -139,18 +165,19 @@ int main(int argc, char *argv[])
                 
                 /* burst error state - 50% bit error rate */
 
-                for(i=0; i<nbit; i++) {
+                for(i=nstart_bit; i<nend_bit+1; i++) {
                     r = (float)rand()/RAND_MAX;
                     if (r < 0.5) {
                         byte = i/8;
-                        bits[byte] ^= 1 << (i - byte*8);
+                        bits[byte] ^= 1 << (7 - i - byte*8);
                         bit_errors++;
                     }
                }
 
-               r = (float)rand()/RAND_MAX;
-                if (r > pstate1)
+                if (burst_timer > burst_period) {
+                    burst_timer = 0.0;
                     next_state = 0;
+                }
                 break;
 
            }
@@ -166,7 +193,7 @@ int main(int argc, char *argv[])
         if (fin == stdin) fflush(stdin);         
     }
 
-    if (ber != 0.0)
+    if (error_mode)
        fprintf(stderr, "actual BER: %1.3f\n", (float)bit_errors/(frames*nbit));
 
     codec2_destroy(codec2);