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#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# The MIT License (MIT)
#
# Copyright (c) 2016 Matthias P. Braendli
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
#
# A UECP decoder, reading from a UDP socket, receiving
# data generated by my patched VLC, from ancillary MP2 bytes in a MPEG-TS
#
# Please refer to RDS UECP specification
import sys
import socket
import struct
import crc
verbose=False
def log(msg):
if verbose:
print(msg)
# Message Element Codes
uecp_mec_names = {
0x01: "PI" , # Program Identification
0x02: "PS" , # Program Service name
0x06: "PIN" , # Program Item Number
0x04: "DI_PTYI" , # Decoder Information / Dynamic PTY Indicator
0x03: "TA_TP" , # Traffic Anouncement / Traffic Programme
0x05: "MS" , # Music / Speech switch
0x07: "PTY" , # Programme Type
0x3E: "PTYN" , # Programme Type Name
0x0A: "RT" , # RadioText
0x0D: "RTC" , # Real Time Clock
0x19: "CT" , # Enable RTC (group 4 version A) transmits
0x1C: "DSN_SELECT" , # Set active Data Set
0x0B: "PSN_ENABLE" , # Enable / disable a specific PSN
0x1E: "RDSON" , # Enable / disable the RDS output signal
0x23: "SET_SITE_ADDR" , # Add a site address to the encoder
0x27: "SET_ENC_ADDR" , # Add an encoder address to the encoder
0x17: "MSG_REQUEST" , # Request data from the encoder
0x18: "MSG_ACK" , # ACK of a received message
0x2C: "SET_COMM_MODE" } # Set communication mode for the encoder
def usage():
print("Usage:\n{} <port>".format(sys.argv[0]))
if len(sys.argv) < 2:
usage()
sys.exit(1)
class UECP_Message_Decoder():
def __init__(self, message_bytes):
"""Create a message decoder that creates
Message Elements from a message"""
self.message = message_bytes
self.mec = message_bytes[0]
if not(0x01 <= self.mec <= 0xFD):
raise ValueError("MEC 0x{:02x} out of range".format(self.mec))
if self.mec in uecp_mec_names:
name = uecp_mec_names[self.mec]
log(" MEC={}".format(name))
if name == "PS":
dsn = message_bytes[1]
psn = message_bytes[2]
ps = message_bytes[3:-1]
log(" PS DSN={:02x} PSN={:02x} ".format(dsn, psn) + "".join(chr(d) for d in ps))
elif name == "RT":
dsn = message_bytes[1]
psn = message_bytes[2]
mel = message_bytes[3]
med = message_bytes[4:]
buffer_config = (med[0] & 0b01100000) >> 5
number_of_tx = (med[0] & 0b00011110) >> 1
toggle_a_b_flag = (med[0] & 0b00000001)
radiotext = "".join(chr(d) for d in med[1:])
log(" RT DSN={:02x} PSN={:02x} MEL={:02}, ".format(dsn, psn, mel) + radiotext)
print(radiotext)
else:
log(" MEC={}".format(self.mec))
class UECP_Frame_Decoder():
def __init__(self):
"""Create a new decoder from bytes containing a
complete UECP frame, from STA to STO.
See 2.2.1 General Frame Format"""
self.next_untrap = False
self.message_begin_seen = False
self.data = []
def add_byte(self, b):
"""Unescapes characters as defined in 2.2.9
Returns True if more data is needed"""
if self.next_untrap:
self.next_untrap = False
if b == 0x00:
self.data.append(0xFD)
elif b == 0x01:
self.data.append(0xFE)
elif b == 0x02:
self.data.append(0xFF)
else:
raise ValueError("untrap 0x{:02x} invalid".format(b))
elif b == 0xFD and self.message_begin_seen:
self.next_untrap = True
elif b == 0xFE and not self.message_begin_seen:
self.message_begin_seen = True
self.data.append(b)
elif b == 0xFF and self.message_begin_seen:
# end of message
self.data.append(b)
self.decode_frame()
return False
elif self.message_begin_seen:
self.data.append(b)
else:
#log("Dropping 0x{:02x}".format(b))
pass
return True
def check_crc(self):
if 0:
log("B " + " ".join("{:02x}".format(b) for b in self.data))
for i in range(1, len(self.data)):
log(" i={:02} crc=0x{:04x} calc1=0x{:04x} calc2=0x{:04x}".format(i,
self.crc,
0xffff ^ crc.crc16(self.data[1:i]),
crc.crc_ccitt(self.data[1:i])))
self.crc_calc = crc.crc_ccitt(self.data[1:4+self.mfl])
return self.crc_calc == self.crc
def decode_frame(self):
"""Decodes an untrapped frame"""
if verbose:
log("Decoding " + " ".join("{:02x}".format(b) for b in self.data))
self.addr = self.data[1] * 256 + self.data[2]
self.sqc = self.data[3]
self.mfl = self.data[4]
self.msg = self.data[5:5+self.mfl]
if self.mfl + 8 != len(self.data):
raise ValueError("MFL {}, expected {}".format(self.mfl, len(self.data) - 8))
self.crc = self.data[5+self.mfl] * 256 + self.data[5+self.mfl+1]
self.crc_ok = self.check_crc()
UECP_Message_Decoder(self.msg)
uecp = UECP_Frame_Decoder()
def parse_anc_bytes(anc_bytes):
global uecp
for b in anc_bytes:
need_more_data = uecp.add_byte(b)
if not need_more_data:
uecp.decode_frame()
log("Addr={} sqc={} mfl={} msg={} crc=0x{:04x} crc_calc=0x{:04x} ok={}".format(
uecp.addr, uecp.sqc, uecp.mfl,
uecp.msg, uecp.crc, uecp.crc_calc, uecp.crc_ok))
uecp = UECP_Frame_Decoder()
UDP_IP = "127.0.0.1"
port = int(sys.argv[1])
sock = socket.socket(socket.AF_INET, # Internet
socket.SOCK_DGRAM) # UDP
sock.bind((UDP_IP, port))
while True:
data, addr = sock.recvfrom(1024)
if not data:
break
line_bytes = list(data)
line_bytes.reverse()
anc_header = line_bytes[0]
anc_bytes = None
if anc_header == 0xfd:
anc_len = line_bytes[1]
if anc_len > 0:
anc_bytes = line_bytes[2:2+anc_len]
elif anc_header != 0x00:
anc_len = line_bytes[0]
if anc_len > 0:
anc_bytes = line_bytes[1:1+anc_len]
if anc_bytes:
try:
parse_anc_bytes(anc_bytes)
except ValueError as e:
log("***** Error on line {}: {}".format(line_nr+1, e))
uecp = UECP_Frame_Decoder()
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