Much faster LDPC encoder.

PacketTX.py

@@ -5,6 +5,13 @@
 # Frames packets (preamble, unique word, checksum)
 # and transmits them out of a serial port.
 #
+#	RPI UART Calibration
+#	9600  -> 9600.1536
+#	19200 -> 19200.307
+#	38400 -> 38339.148
+#	57600 -> 57693.417
+#  115200 -> 115386.834
+#
 # Mark Jessop <vk5qi@rfhead.net>
 #
 
@@ -34,9 +41,9 @@ class BinaryDebug(object):
 		self.f.close()
 
 def write_debug_message(message, debug_file = "tx_idle_message.txt"):
-	f = open(debug_file,'w')
+	#f = open(debug_file,'w')
-	f.write(message)
+	#f.write(message)
-	f.close()
+	#f.close()
 	print("DEBUG MSG: %s" % message)
 
 class PacketTX(object):
@@ -59,8 +66,9 @@ class PacketTX(object):
 		self.payload_length = payload_length
 
 		self.crc16 = crcmod.predefined.mkCrcFun('crc-ccitt-false')
-		self.fec = fec
 		self.callsign = callsign
+		self.idle_message = "DE %s" % callsign
+		self.fec = fec
 
 	def start_tx(self):
 		self.transmit_active = True
@@ -82,18 +90,17 @@ class PacketTX(object):
 		else:
 			return self.preamble + self.unique_word + packet + crc 
 
+
+	def set_idle_message(self, message):
+		temp_msg = "\x00" + "DE %s: \t%s" % (self.callsign, message)
+		self.idle_message = self.frame_packet(temp_msg)
+
+
 	# Either generate an idle message, or read one in from a file (tx_idle_message.txt) if it exists.
 	# This might be a useful way of getting error messages down from the payload.
 	def generate_idle_message(self):
-		# Try and read in a message from a file.
-		try:
-			f = open("tx_idle_message.txt")
-			idle_data = "DE %s: \t%s" % (self.callsign,f.read())
-			f.close()
-		except:
-			idle_data = "DE %s Wenet High-Speed FSK Transmitter" % self.callsign
 		# Append a \x00 control code before the data
-		return "\x00" + idle_data
+		return "\x00" + "DE %s: \t%s" % (self.callsign,self.idle_message)
 
 
 	def tx_thread(self):
@@ -104,7 +111,7 @@ class PacketTX(object):
 			else:
 				if not self.debug:
 					#self.s.write(self.idle_sequence)
-					self.s.write(self.frame_packet(self.generate_idle_message()))
+					self.s.write(self.idle_message)
 				else:
 					sleep(0.05)
 		

ldpc_enc.c

@@ -0,0 +1,40 @@
+/*
+
+LDPC Encoder, using a 'RA' encoder written by Bill Cowley VK5DSP in March 2016.
+
+Compile with:
+gcc -fPIC -shared -o ldpc_enc.so ldpc_enc.c
+
+
+*/
+
+#include<stdio.h>
+#include<stdlib.h>
+#define Nibits 2064
+#define Npbits 516
+#define Nwt     12
+
+
+unsigned short hrows[] = { 
+// read from file created via make_Hrows_txt.m
+// use the new code of March 2016 
+#include "Hrow2064.txt"
+};
+
+
+void encode(unsigned char *ibits, unsigned char *pbits)   {
+  unsigned int   p, i, tmp, par, prev=0;
+  char c;  
+  for (p=0; p<Npbits; p++)   {
+    par =0; 
+    for (i=0; i<Nwt; i++)  
+      par = par + ibits[hrows[p*Nwt+i]-1];
+      // -1 as matlab arrays start from 1, C from 0
+    tmp = par + prev;
+    //printf(" p ind %d, parity  %d  \n", p, tmp);  
+    //c = getchar();  
+    tmp &= 1;    // only retain the lsb 
+    prev = tmp; 
+    pbits[p] =tmp; 
+  }
+}

ldpc_encoder.py

@@ -1,94 +1,53 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python
 #
-# LDPC Encoder based on C code from Bill Cowley in March 2016
+#   LDPC Encoder Functions.
-# Author: Mark Jessop <vk5qi@rfhead.net>
+#   Uses ctypes to call the encode function from ldpc_enc.c
 #
+#   ldpc_enc.c needs to be compiled to a .so before this will work, with:
+#   gcc -fPIC -shared -o ldpc_enc.so ldpc_enc.c
+#
+#   Mark Jessop <vk5qi@rfhead.net>
+#
+
+import ctypes
+from numpy.ctypeslib import ndpointer
 import numpy as np
+import time
+
+
+# Attempt to load in ldpc_enc.so on startup.
+try:
+    _ldpc_enc = ctypes.CDLL("./ldpc_enc.so")
+    _ldpc_enc.encode.restype = None
+    _ldpc_enc.encode.argtypes = (ndpointer(ctypes.c_ubyte, flags="C_CONTIGUOUS"), ndpointer(ctypes.c_ubyte, flags="C_CONTIGUOUS"))
+except OSError as e:
+    raise OSError("Could not find ldpc_enc.so! Have you compiled ldpc_enc.c?")
 
 #
-# ORIGINAL C CODE FOLLOWS
+#   LDPC Encoder.
+#   Accepts a 258 byte string as input, returns the LDPC parity bits.
 #
 
-# #define Nibits 2064
+def ldpc_encode_string(payload, Nibits = 2064, Npbits = 516):
-# #define Npbits 516
-# #define Nwt     12
-
-
-# unsigned short hrows[] = { 
-# // read from file created via make_Hrows_txt.m
-# // use the new code of March 2016 
-# #include "Hrow2064.txt"
-# };
-
-# unsigned char  ibits[Nibits];    // info array 
-# unsigned char  pbits[Npbits];    // parity array 
-
-# void encode()   {
-#   unsigned int   p, i, tmp, par, prev=0;
-#   char c;  
-#   for (p=0; p<Npbits; p++)   {
-#     par =0; 
-#     for (i=0; i<Nwt; i++)  
-#       par = par + ibits[hrows[p*Nwt+i]-1];
-#       // -1 as matlab arrays start from 1, C from 0
-#     tmp = par + prev;
-#     // printf(" p ind %d, parity  %d  \n", p, tmp);  
-#     //c = getchar();  
-#     tmp &= 1;    // only retain the lsb 
-#     prev = tmp; 
-#     pbits[p] =tmp; 
-#   }
-# }
-
-
-# Load Parity table upon load of this library.
-hrows_2064 = np.loadtxt("ldpc_2064.txt",delimiter=',',comments='#').astype(np.int)
-
-
-# Direct port of encode() above.
-# Takes an input array of 0s and 1s.
-# Should look at vectorising this somehow.
-#@profile
-def ldpc_encode(ibits,Nibits=2064,Npbits=516,Nwt=12,hrows=hrows_2064):
-    prev = 0
-    pbits = np.zeros(Npbits)
-
-    for p in xrange(Npbits):
-        #par = 0
-        #for i in xrange(Nwt):
-        #    par = par + ibits[hrows[p*Nwt+i]-1]
-        par = int(np.sum(ibits[hrows[(p*Nwt+np.arange(Nwt))]-1])) # Some vectorisation of the above.
-
-        tmp = (par + prev)&1
-        prev = tmp
-        pbits[p] = tmp
-
-    return pbits
-
-# Wrapper function for the above, allowing LDPC coding of a 258 byte long string.
-def ldpc_encode_string(payload,Nibits=2064,Npbits=516,Nwt=12,hrows=hrows_2064):
     if len(payload) != 258:
         raise TypeError("Payload MUST be 258 bytes in length! (2064 bit codeword)")
 
-    # Convert to bits.
+    # Get input data into the right form (list of 0s and 1s)
-    raw_data = np.array([],dtype=np.uint8)
+    ibits = np.unpackbits(np.fromstring(payload,dtype=np.uint8)).astype(np.uint8)
-    ibits = np.unpackbits(np.fromstring(payload,dtype=np.uint8))
+    pbits = np.zeros(Npbits).astype(np.uint8)
 
-    parity = ldpc_encode(ibits,Nibits,Npbits,Nwt,hrows)
+    _ldpc_enc.encode(ibits, pbits)
 
-    return np.packbits(parity.astype(np.uint8)).tostring()
+    return np.packbits(np.array(list(pbits)).astype(np.uint8)).tostring()
 
 
-#
+# Some testing functions, to time encoding performance.
-#   Testing Stuff
-#
 
 def generate_dummy_packet():
     payload = np.arange(0,256,1)
     payload = np.append(payload,[0,0]).astype(np.uint8).tostring() # Add on dummy checksum, for a total of 258 bytes.
     return payload
 
-#@profile
 def main():
     # Generate a dummy test packet, and convert it to an array of 0 and 1.
     payload = generate_dummy_packet()
@@ -97,12 +56,17 @@ def main():
 
     # Now run ldpc_encode over it X times.
     parity = ""
-    for x in xrange(100):
+    start = time.time()
-        parity = ldpc_encode_string(payload)
+    for x in xrange(1000):
+        #print(x)
+        parity = ldpc_encode(payload)
+
+    stop = time.time()
+    print("time delta: %.3f" % (stop-start))
 
     print("LDPC Parity Bits (hex): %s" % ("".join("{:02x}".format(ord(c)) for c in parity)))
     print("Done!")
 
 # Some basic test code.
 if __name__ == "__main__":
-    main()
+    main()

tx_picam.py

@@ -15,19 +15,19 @@ try:
 	if len(callsign)>6:
 		callsign = callsign[:6]
 except:
-	print("Usage: python tx_picam.py CALLSIGN")
+	print("Usage: python tx_picam.py CALLSIGN ")
 	sys.exit(1)
 
 print("Using callsign: %s" % callsign)
 
-
+fec = False
 debug_output = False # If True, packet bits are saved to debug.bin as one char per bit.
 
 def transmit_file(filename, tx_object):
 	file_size = os.path.getsize(filename)
 
 	if file_size % 256 > 0:
-		write_debug_message("File size not a multiple of 256 bytes!")
+		tx.set_idle_message("File size not a multiple of 256 bytes!")
 		return
 
 	print("Transmitting %d Packets." % (file_size/256))
@@ -43,7 +43,7 @@ def transmit_file(filename, tx_object):
 	tx_object.wait()
 
 
-tx = PacketTX.PacketTX(debug=debug_output, callsign=callsign)
+tx = PacketTX.PacketTX(debug=debug_output, callsign=callsign, fec=fec)
 tx.start_tx()
 
 image_id = 0
@@ -53,10 +53,10 @@ try:
 		# Capture image using PiCam
 		print("Capturing Image...")
 		capture_time = datetime.datetime.utcnow().strftime("%Y%m%d-%H%M%SZ")
-		capture_multiple(filename="./tx_images/%s.jpg"%capture_time)
+		capture_multiple(filename="./tx_images/%s.jpg"%capture_time, debug_ptr = tx.set_idle_message)
 		#os.system("raspistill -t 100 -o ./tx_images/%s.jpg -vf -hf -w 1024 -h 768" % capture_time)
 		# Resize using convert
-		write_debug_message("Converting Image to SSDV...")
+		tx.set_idle_message("Converting Image to SSDV...")
 		#os.system("convert temp.jpg -resize %s\! temp.jpg" % tx_resolution)
 		# SSDV'ify the image.
 		os.system("ssdv -e -n -c %s -i %d ./tx_images/%s.jpg temp.ssdv" % (callsign,image_id,capture_time))

tx_picam_rate_test.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+#
+#	PiCam Transmitter Script
+#	Capture images from the PiCam, and transmit them.
+#	Multiple baud rate test version.
+#
+#	Mark Jessop <vk5qi@rfhead.net>
+#
+
+import PacketTX,  sys, os, datetime, time
+from PacketTX import write_debug_message
+from wenet_util import *
+
+try:
+	callsign = sys.argv[1]
+	if len(callsign)>6:
+		callsign = callsign[:6]
+except:
+	print("Usage: python tx_picam.py CALLSIGN ")
+	sys.exit(1)
+
+print("Using callsign: %s" % callsign)
+
+
+fec = False
+debug_output = False # If True, packet bits are saved to debug.bin as one char per bit.
+
+baud_rate_1 = 115200
+baud_rate_2 = 19200
+
+def transmit_file(filename, tx_object):
+	file_size = os.path.getsize(filename)
+
+	if file_size % 256 > 0:
+		tx.set_idle_message("File size not a multiple of 256 bytes!")
+		return
+
+	print("Transmitting %d Packets." % (file_size/256))
+
+	f = open(filename,'rb')
+
+	for x in range(file_size/256):
+		data = f.read(256)
+		tx_object.tx_packet(data)
+
+	f.close()
+	print("Waiting for tx queue to empty...")
+	tx_object.wait()
+
+tx = PacketTX.PacketTX(debug=debug_output, callsign=callsign,serial_baud=baud_rate_1)
+tx.start_tx()
+
+image_id = 0
+
+try:
+	while True:
+		# Capture image using PiCam
+		print("Capturing Image...")
+		capture_time = datetime.datetime.utcnow().strftime("%Y%m%d-%H%M%SZ")
+		capture_multiple(filename="./tx_images/%s.jpg"%capture_time, debug_ptr = tx.set_idle_message)
+		#os.system("raspistill -t 100 -o ./tx_images/%s.jpg -vf -hf -w 1024 -h 768" % capture_time)
+		# Resize using convert
+		tx.set_idle_message("Converting Image to SSDV...")
+		#os.system("convert temp.jpg -resize %s\! temp.jpg" % tx_resolution)
+		# SSDV'ify the image.
+		os.system("ssdv -e -n -c %s -i %d ./tx_images/%s.jpg temp.ssdv" % (callsign,image_id,capture_time))
+		# Transmit image
+		print("Transmitting...")
+
+		# Transmit first in 115200 baud.
+		transmit_file("temp.ssdv",tx)
+		tx.close()
+		time.sleep(2)
+
+		# Transmit again in 19200 baud
+		tx = PacketTX.PacketTX(debug=debug_output, callsign=callsign, serial_baud=baud_rate_2, fec = fec)
+		tx.start_tx()
+		transmit_file("temp.ssdv",tx)
+		tx.close()
+		time.sleep(2)
+
+		# Re-open TX in 115200 baud.
+		tx = PacketTX.PacketTX(debug=debug_output, callsign=callsign, serial_baud=baud_rate_1, fec = fec)
+		tx.start_tx()
+
+		# Increment Counter
+		image_id = (image_id+1)%256
+except KeyboardInterrupt:
+	print("Closing")
+	tx.close()

tx_test_images.py

@@ -9,7 +9,7 @@
 import PacketTX,  sys, os
 
 # Set to whatever resolution you want to test.
-file_path = "./test_images/%d_320x240.ssdv" # _raw, _800x608, _640x480, _320x240
+file_path = "./test_images/%d_raw.ssdv" # _raw, _800x608, _640x480, _320x240
 image_numbers = xrange(1,14)
 
 debug_output = True # If True, packet bits are saved to debug.bin as one char per bit.
@@ -34,15 +34,15 @@ def transmit_file(filename, tx_object):
 	tx_object.wait()
 
 
-tx = PacketTX.PacketTX(debug=debug_output)
+tx = PacketTX.PacketTX(debug=debug_output,fec=False)
 tx.start_tx()
 print("TX Started. Press Ctrl-C to stop.")
 try:
-	while True:
+	for img in image_numbers:
-		for img in image_numbers:
+		filename = file_path % img
-			filename = file_path % img
+		print("\nTXing: %s" % filename)
-			print("\nTXing: %s" % filename)
+		transmit_file(filename,tx)
-			transmit_file(filename,tx)
+	tx.close()
 except KeyboardInterrupt:
 	print("Closing...")
 	tx.close()