FreeDATA/modem.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Wed Dec 23 07:04:24 2020

@author: DJ2LS
"""

import ctypes
from ctypes import *
import pathlib
import pyaudio
import audioop
#import sys
import logging
import time
import threading

import helpers
import static
import arq








class RF():
    
    def __init__(self):  
        #-------------------------------------------- LOAD FREEDV
        libname = pathlib.Path().absolute() / "codec2/build_linux/src/libcodec2.so"
        self.c_lib = ctypes.CDLL(libname)
        #--------------------------------------------CREATE PYAUDIO  INSTANCE
        self.p = pyaudio.PyAudio()
        #--------------------------------------------GET SUPPORTED SAMPLE RATES FROM SOUND DEVICE
        #static.AUDIO_SAMPLE_RATE_RX = int(self.p.get_device_info_by_index(static.AUDIO_INPUT_DEVICE)['defaultSampleRate'])
        #static.AUDIO_SAMPLE_RATE_TX = int(self.p.get_device_info_by_index(static.AUDIO_OUTPUT_DEVICE)['defaultSampleRate'])
        static.AUDIO_SAMPLE_RATE_TX = 8000
        static.AUDIO_SAMPLE_RATE_RX = 8000
        #--------------------------------------------OPEN AUDIO CHANNEL RX
        self.stream_rx = self.p.open(format=pyaudio.paInt16, 
                            channels=static.AUDIO_CHANNELS,
                            rate=static.AUDIO_SAMPLE_RATE_RX,
                            frames_per_buffer=static.AUDIO_FRAMES_PER_BUFFER,
                            input=True,
                            input_device_index=static.AUDIO_INPUT_DEVICE,
                            ) 
        #--------------------------------------------OPEN AUDIO CHANNEL TX
        self.stream_tx = self.p.open(format=pyaudio.paInt16,
                            channels=1,
                            rate=static.AUDIO_SAMPLE_RATE_TX,
                            frames_per_buffer=static.AUDIO_FRAMES_PER_BUFFER, #n_nom_modem_samples
                            output=True,
                            output_device_index=static.AUDIO_OUTPUT_DEVICE,  #static.AUDIO_OUTPUT_DEVICE
                            )  
        #--------------------------------------------START DECODER THREAD                
        FREEDV_DECODER_THREAD = threading.Thread(target=self.receive, args=[static.FREEDV_DATA_MODE,static.FREEDV_SIGNALLING_MODE], name="FREEDV_DECODER_THREAD")
        FREEDV_DECODER_THREAD.start()  

#--------------------------------------------------------------------------------------------------------     
    def transmit_arq_ack(self,ack_buffer):
        #print(ack_buffer)
        static.ARQ_STATE = 'SENDING_ACK'
    
        self.c_lib.freedv_open.restype = ctypes.POINTER(ctypes.c_ubyte)
        freedv = self.c_lib.freedv_open(static.FREEDV_SIGNALLING_MODE)
        bytes_per_frame = int(self.c_lib.freedv_get_bits_per_modem_frame(freedv)/8)
        payload_per_frame = bytes_per_frame -2
        n_nom_modem_samples = self.c_lib.freedv_get_n_nom_modem_samples(freedv)
        n_tx_modem_samples = self.c_lib.freedv_get_n_tx_modem_samples(freedv)*2 #get n_tx_modem_samples which defines the size of the modulation object
          
        mod_out = ctypes.c_short * n_tx_modem_samples
        mod_out = mod_out()
        mod_out_preamble = ctypes.c_short * (1760*2) #1760 for mode 10,11,12 #4000 for mode 9
        mod_out_preamble = mod_out_preamble()

        buffer = bytearray(payload_per_frame) # use this if CRC16 checksum is required ( DATA1-3)
        buffer[:len(ack_buffer)] = ack_buffer # set buffersize to length of data which will be send

        crc = ctypes.c_ushort(self.c_lib.freedv_gen_crc16(bytes(buffer), payload_per_frame))     # generate CRC16
        crc = crc.value.to_bytes(2, byteorder='big') # convert crc to 2 byte hex string
        buffer += crc        # append crc16 to buffer
        data = (ctypes.c_ubyte * bytes_per_frame).from_buffer_copy(buffer)
        
        preamble_bytes = self.c_lib.freedv_rawdatapreambletx(freedv, mod_out_preamble)
        self.c_lib.freedv_rawdatatx(freedv,mod_out,data) # modulate DATA and safe it into mod_out pointer     
        txbuffer = bytearray()    
        txbuffer += bytes(mod_out_preamble)
        txbuffer = txbuffer.rstrip(b'\x00') #lets remove unallocated memory because of wrong buffer :-/
        txbuffer += bytes(mod_out)
        txbuffer = txbuffer.rstrip(b'\x00') #lets remove unallocated memory because of wrong buffer :-/
        
        # -------------- transmit audio twice
        
        logging.debug("SEND SIGNALLING FRAME " + str(ack_buffer))
        self.stream_tx.write(bytes(txbuffer))
        self.stream_tx.write(bytes(txbuffer))

        static.ARQ_STATE = 'RECEIVING_DATA'
#--------------------------------------------------------------------------------------------------------     
   # GET ARQ BURST FRAME VOM BUFFER AND MODULATE IT 
    def transmit_arq_burst(self):
        
        static.ARQ_STATE = 'SENDING_DATA'

        self.c_lib.freedv_open.restype = ctypes.POINTER(ctypes.c_ubyte)
        freedv = self.c_lib.freedv_open(static.FREEDV_DATA_MODE)
        static.FREEDV_DATA_BYTES_PER_FRAME = int(self.c_lib.freedv_get_bits_per_modem_frame(freedv)/8)
        static.FREEDV_DATA_PAYLOAD_PER_FRAME = static.FREEDV_DATA_BYTES_PER_FRAME -2
         
        n_nom_modem_samples = self.c_lib.freedv_get_n_nom_modem_samples(freedv)
        n_tx_modem_samples = self.c_lib.freedv_get_n_tx_modem_samples(freedv)*2 #get n_tx_modem_samples which defines the size of the modulation object
          
        mod_out = ctypes.c_short * n_tx_modem_samples
        mod_out = mod_out()
        mod_out_preamble = ctypes.c_short * (n_tx_modem_samples*2) #1760 for mode 10,11,12 #4000 for mode 9
        mod_out_preamble = mod_out_preamble()

        self.c_lib.freedv_rawdatapreambletx(freedv, mod_out_preamble);
        txbuffer = bytearray()
        txbuffer += bytes(mod_out_preamble)
        txbuffer = txbuffer.rstrip(b'\x00') #lets remove unallocated memory because of wrong buffer :-/
        
        if static.ARQ_RPT_RECEIVED == False:
            for n in range(0,static.ARQ_TX_N_FRAMES_PER_BURST):

            #---------------------------BUILD ARQ BURST ---------------------------------------------------------------------
                frame_type = 10 + n + 1 #static.ARQ_TX_N_FRAMES_PER_BURST
                frame_type = bytes([frame_type])

                payload_data = bytes(static.TX_BUFFER[static.ARQ_N_SENT_FRAMES + n])
            
                n_current_arq_frame = static.ARQ_N_SENT_FRAMES + n + 1
                static.ARQ_TX_N_CURRENT_ARQ_FRAME = n_current_arq_frame.to_bytes(2, byteorder='big')
            
                n_total_arq_frame = len(static.TX_BUFFER)
                static.ARQ_TX_N_TOTAL_ARQ_FRAMES = n_total_arq_frame.to_bytes(2, byteorder='big')
             
                arqframe = frame_type + \
                       bytes([static.ARQ_TX_N_FRAMES_PER_BURST]) + \
                       static.ARQ_TX_N_CURRENT_ARQ_FRAME + \
                       static.ARQ_TX_N_TOTAL_ARQ_FRAMES + \
                       static.DXCALLSIGN_CRC8 + \
                       static.MYCALLSIGN_CRC8 + \
                       payload_data                                      
                    
                #print(arqframe)
                    
                buffer = bytearray(static.FREEDV_DATA_PAYLOAD_PER_FRAME) # create TX buffer 
                buffer[:len(arqframe)] = arqframe # set buffersize to length of data which will be send
                                
                crc = ctypes.c_ushort(self.c_lib.freedv_gen_crc16(bytes(buffer), static.FREEDV_DATA_PAYLOAD_PER_FRAME))     # generate CRC16
                crc = crc.value.to_bytes(2, byteorder='big') # convert crc to 2 byte hex string
                buffer += crc        # append crc16 to buffer

                data = (ctypes.c_ubyte * static.FREEDV_DATA_BYTES_PER_FRAME).from_buffer_copy(buffer)
                self.c_lib.freedv_rawdatatx(freedv,mod_out,data) # modulate DATA and safe it into mod_out pointer 
                txbuffer += bytes(mod_out)
                txbuffer = txbuffer.rstrip(b'\x00') #lets remove unallocated memory because of wrong buffer :-/

        elif static.ARQ_RPT_RECEIVED == True:
            
            for n in range(0,len(static.ARQ_RPT_FRAMES)):

                missing_frame = int.from_bytes(static.ARQ_RPT_FRAMES[n], "big")
                               
            #---------------------------BUILD ARQ BURST ---------------------------------------------------------------------
                frame_type = 10 + missing_frame #static.ARQ_TX_N_FRAMES_PER_BURST
                frame_type = bytes([frame_type])

                payload_data = bytes(static.TX_BUFFER[static.ARQ_N_SENT_FRAMES + missing_frame - 1])
            
                n_current_arq_frame = static.ARQ_N_SENT_FRAMES + missing_frame
                static.ARQ_TX_N_CURRENT_ARQ_FRAME = n_current_arq_frame.to_bytes(2, byteorder='big')
            
                n_total_arq_frame = len(static.TX_BUFFER)
                static.ARQ_TX_N_TOTAL_ARQ_FRAMES = n_total_arq_frame.to_bytes(2, byteorder='big')
             
                arqframe = frame_type + \
                       bytes([static.ARQ_TX_N_FRAMES_PER_BURST]) + \
                       static.ARQ_TX_N_CURRENT_ARQ_FRAME + \
                       static.ARQ_TX_N_TOTAL_ARQ_FRAMES + \
                       static.DXCALLSIGN_CRC8 + \
                       static.MYCALLSIGN_CRC8 + \
                       payload_data                                      

                #print(arqframe)

                buffer = bytearray(static.FREEDV_DATA_PAYLOAD_PER_FRAME) # create TX buffer 
                buffer[:len(arqframe)] = arqframe # set buffersize to length of data which will be send
                                
                crc = ctypes.c_ushort(self.c_lib.freedv_gen_crc16(bytes(buffer), static.FREEDV_DATA_PAYLOAD_PER_FRAME))     # generate CRC16
                crc = crc.value.to_bytes(2, byteorder='big') # convert crc to 2 byte hex string
                buffer += crc        # append crc16 to buffer

                data = (ctypes.c_ubyte * static.FREEDV_DATA_BYTES_PER_FRAME).from_buffer_copy(buffer)
                self.c_lib.freedv_rawdatatx(freedv,mod_out,data) # modulate DATA and safe it into mod_out pointer 
                txbuffer += bytes(mod_out)
                txbuffer = txbuffer.rstrip(b'\x00') #lets remove unallocated memory because of wrong buffer :-/            
        
       
        # -------------- transmit audio
        self.stream_tx.write(bytes(txbuffer)) 
        #time.sleep(0.5)
        static.ARQ_STATE = 'IDLE'
        #static.ARQ_STATE = 'RECEIVING_SIGNALLING'
        
#--------------------------------------------------------------------------------------------------------         
    def receive(self,data_mode,signalling_mode):
        force = False
        
        self.c_lib.freedv_open.restype = ctypes.POINTER(ctypes.c_ubyte)
        
        freedv_data = self.c_lib.freedv_open(data_mode)
        freedv_signalling = self.c_lib.freedv_open(signalling_mode)      

        static.FREEDV_DATA_BYTES_PER_FRAME = int(self.c_lib.freedv_get_bits_per_modem_frame(freedv_data)/8)
        static.FREEDV_DATA_PAYLOAD_PER_FRAME = static.FREEDV_DATA_BYTES_PER_FRAME -2
        static.FREEDV_SIGNALLING_BYTES_PER_FRAME = int(self.c_lib.freedv_get_bits_per_modem_frame(freedv_signalling)/8)
        static.FREEDV_SIGNALLING_PAYLOAD_PER_FRAME = static.FREEDV_SIGNALLING_BYTES_PER_FRAME -2
  
        data_bytes_out = (ctypes.c_ubyte * static.FREEDV_DATA_BYTES_PER_FRAME)
        data_bytes_out = data_bytes_out() #get pointer from bytes_out    

        signalling_bytes_out = (ctypes.c_ubyte * static.FREEDV_SIGNALLING_BYTES_PER_FRAME)
        signalling_bytes_out = signalling_bytes_out() #get pointer from bytes_out 

        # with this we can interrupt receiving        
        while static.FREEDV_RECEIVE == True:
            time.sleep(0.01)
            
            # stuck in sync counter
            stuck_in_sync_counter = 0
            stuck_in_sync_10_counter = 0
            #
                     
            while static.ARQ_STATE == 'RECEIVING_DATA':
                time.sleep(0.01)
                
                nin = self.c_lib.freedv_nin(freedv_data)
                #nin = int(nin*(static.AUDIO_SAMPLE_RATE_RX/static.MODEM_SAMPLE_RATE))

                data_in = self.stream_rx.read(nin,  exception_on_overflow = False)  
                #print(audioop.rms(data_in, 2))
                data_in = data_in.rstrip(b'\x00')
                
                #print(data_in)
                
                #self.c_lib.freedv_rawdatarx.argtype = [ctypes.POINTER(ctypes.c_ubyte), data_bytes_out, data_in] # check if really neccessary 
                nbytes = self.c_lib.freedv_rawdatarx(freedv_data, data_bytes_out, data_in) # demodulate audio
                logging.debug(self.c_lib.freedv_get_rx_status(freedv_data))
                
                #-------------STUCK IN SYNC DETECTOR            
                stuck_in_sync_counter += 1
                if self.c_lib.freedv_get_rx_status(freedv_data) == 10:
                    stuck_in_sync_10_counter += 1
                    
                    
                if stuck_in_sync_counter == 33 and self.c_lib.freedv_get_rx_status(freedv_data) == 10:
                    logging.critical("stuck in sync #1")
                    self.c_lib.freedv_set_sync(freedv_data, 0) #FORCE UNSYNC
                    stuck_in_sync_counter = 0
                    stuck_in_sync_10_counter = 0
                    data_in = None
  
                    
                if stuck_in_sync_counter >= 66 and stuck_in_sync_10_counter >= 2:
                    logging.critical("stuck in sync #2")
                    self.c_lib.freedv_set_sync(freedv_data, 0) #FORCE UNSYNC
                    stuck_in_sync_counter = 0    
                    stuck_in_sync_10_counter = 0
                    data_in = None
                #-----------------------------------
            
 
                if nbytes == static.FREEDV_DATA_BYTES_PER_FRAME:
                    
                    # counter reset for stuck in sync counter
                    stuck_in_sync_counter = 0
                    stuck_in_sync_10_counter = 0
                    #
                                          
                    # CHECK IF FRAMETYPE IS BETWEEN 10 and 50 ------------------------
                    frametype = int.from_bytes(bytes(data_bytes_out[:1]), "big")
                    frame = frametype - 10
                    n_frames_per_burst = int.from_bytes(bytes(data_bytes_out[1:2]), "big")    
     
                    if 50 >= frametype >= 10:                     
                        if frame != 3 or force == True:
                            arq.data_received(bytes(data_bytes_out[:-2])) #send payload data to arq checker without CRC16 
                                            
                            #print("static.ARQ_RX_BURST_BUFFER.count(None) " + str(static.ARQ_RX_BURST_BUFFER.count(None)))
                            if static.ARQ_RX_BURST_BUFFER.count(None) <= 1:
                                logging.debug("FULL BURST BUFFER ---> UNSYNC")
                                self.c_lib.freedv_set_sync(freedv_data, 0)
                        
                        else:
                            logging.critical("---------------------------SIMULATED MISSING FRAME")
                            force = True
                    else:
                        logging.info("MODE: " + str(data_mode) + " DATA: " + str(bytes(data_bytes_out)))                                
                
                
                    # DO UNSYNC AFTER LAST BURST by checking the frame numbers agains the total frames per burst
                    if frame == n_frames_per_burst:
                        logging.debug("LAST FRAME ---> UNSYNC")
                        self.c_lib.freedv_set_sync(freedv_data, 0) #FORCE UNSYNC
                        
               
                        
            while static.ARQ_STATE == 'IDLE' or static.ARQ_STATE == 'RECEIVING_SIGNALLING':
                time.sleep(0.01)

                nin = self.c_lib.freedv_nin(freedv_signalling)
                #nin = int(nin*(static.AUDIO_SAMPLE_RATE_RX/static.MODEM_SAMPLE_RATE))

                data_in = self.stream_rx.read(nin,  exception_on_overflow = False)  
                data_in = data_in.rstrip(b'\x00')
                
                #self.c_lib.freedv_rawdatarx.argtype = [ctypes.POINTER(ctypes.c_ubyte), signalling_bytes_out, data_in] # check if really neccessary 
                nbytes = self.c_lib.freedv_rawdatarx(freedv_signalling, signalling_bytes_out, data_in) # demodulate audio
                             
                # CHECK IF FRAME CONTAINS ACK------------------------         
                
                if nbytes == static.FREEDV_SIGNALLING_BYTES_PER_FRAME:
                    self.c_lib.freedv_set_sync(freedv_signalling, 0)
                    frametype = int.from_bytes(bytes(signalling_bytes_out[:1]), "big")
                    
                    # BURST ACK
                    if frametype == 60:
                       logging.debug("ACK RECEIVED....")
                       arq.burst_ack_received()
                       
                    # FRAME ACK
                    elif frametype == 61:
                       logging.debug("FRAME ACK RECEIVED....")
                       arq.frame_ack_received()
                       
                    # FRAME RPT
                    elif frametype == 62:
                       logging.debug("REPEAT REQUEST RECEIVED....")
                       arq.burst_rpt_received(signalling_bytes_out[:-2])

                    else:
                        logging.debug("OTHER FRAME: " + str(signalling_bytes_out[:-2]))
                    
                    
                rxstatus = self.c_lib.freedv_get_rx_status(freedv_signalling)     
                logging.debug("ACK-" + str(rxstatus))
                if nbytes == static.FREEDV_SIGNALLING_BYTES_PER_FRAME or rxstatus == 10:
                    self.c_lib.freedv_set_sync(freedv_signalling, 0) #FORCE UNSYNC