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la_times.py
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la_times.py
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#!/usr/bin/env python
import os
import sys
import math
from datetime import datetime, timedelta
from time import sleep
class Linkset():
def __init__(self, lsn, hard, active):
self.lsn = lsn
self.hard = hard
self.active = active
self.members = {}
class ETI():
def __init__(self):
self.frame_count = 0
self.lto = None
self.time_now = None
self.time_long = False
self.eti_frame = 0
self.last_timestamp = None
self.timestamp_confidence = False
self.linksets = {}
def update_time(self, now):
if self.time_long:
self.time_now = now
else:
if self.time_now == now:
return
if self.time_now and not self.timestamp_confidence:
self.timestamp_confidence = True
self.time_now = now
self.last_timestamp = self.frame_count
def increment_frame_count(self):
self.frame_count += 1
def check_linkset_actuator(self, link_set_number, soft_hard, link_actuator):
if not soft_hard:
soft_hard_label = "S"
else:
soft_hard_label = "H"
if link_actuator:
link_actuator_label = "Active"
else:
link_actuator_label = "Inactive"
linkset_key = "%X%s" % (link_set_number, soft_hard_label)
if not self.linksets.has_key(linkset_key):
linkset = Linkset(link_set_number, soft_hard, link_actuator)
self.linksets[linkset_key] = linkset
self.send_message("First occurance of linkset %s (%s)" % (linkset_key, link_actuator_label))
else:
if self.linksets[linkset_key].active == link_actuator:
return
self.linksets[linkset_key].active = link_actuator
self.send_message("Setting linkset %s to %s" % (linkset_key, link_actuator_label))
def update_link_set_members(self, link_set_number, soft_hard, qualifier, id_list):
updated = False
if not soft_hard:
soft_hard_label = "S"
else:
soft_hard_label = "H"
linkset_key = "%X%s" % (link_set_number, soft_hard_label)
linkset = self.linksets[linkset_key]
if not linkset.members.has_key(qualifier):
linkset.members[qualifier] = []
for id in id_list:
if id not in linkset.members[qualifier]:
linkset.members[qualifier].append(id)
updated = True
if updated:
message = "Updated members of link set %s: " % linkset_key
sub_messages = []
for qualifier in linkset.members:
sub_messages.append("%s - %s " % (qualifier, ", ".join(linkset.members[qualifier])))
message += ", ".join(sub_messages)
self.send_message(message)
def send_message(self, message):
eti_time = str(timedelta(seconds = (self.frame_count * (24.0 / 1000))))
if not self.time_now:
broadcast_time = "unknown"
else:
frame_offset = self.frame_count - self.last_timestamp
if self.timestamp_confidence:
broadcast_time = self.time_now + timedelta(seconds = (frame_offset * (24.0 / 1000)))
else:
broadcast_time = "Approx %s" % self.time_now
print "%s\t%s\t%s\t%s" % (self.frame_count, eti_time, broadcast_time, message)
class Parser():
def __init__(self):
self.eti = ETI()
self.fic_length = 24 # words (1 word = 4 bytes)
def process_frame(self, frame):
# Frame Characterization Field
(frame_count, fic_flag, num_streams, mode) = self.frame_characterization(frame[4:8])
if mode == 3:
self.fic_length = 32
frame_position = 8
for n in range(0, num_streams):
frame_position += 4 # 4 bytes per SSTC
frame_position += 4 # 4 byte EOH, could check header CRC here
# Main Stream Transport
if fic_flag:
fic = frame[frame_position:(frame_position+(self.fic_length * 4))]
try:
self.decode_fic(fic)
except Exception, e:
print "Error decoding fic: %s" % e
def frame_characterization(self, fc):
frame_count = fc[0]
fic_flag = (fc[1] & 0x80) >> 7
num_streams = fc[1] & 0x7f
mode = (fc[2] & 0x18) >> 3
if mode == 0: mode = 4
return (frame_count, fic_flag, num_streams, mode)
def stream_characterization(self, sstc):
scid = int(sstc[0:6].to01(), 2)
sad = int(sstc[6:16].to01(), 2)
tpl = int(sstc[16:22].to01(), 2)
stl = int(sstc[22:32].to01(), 2)
stream = Stream(scid, sad, tpl, stl)
return stream
def end_of_header(self):
self.input_file_handler.read(4)
return
def decode_fic(self, fibs):
i = 0
fib_start = i
while i < (self.fic_length * 4):
# Check to see if reached end marker
if fibs[i] == 0xff:
i = fib_start + 32
fib_start = i
continue
fig_type = (fibs[i] & 0xe0) >> 5
fig_length = (fibs[i] & 0x1f)
fig_data = fibs[i+1:i+1+fig_length]
if fig_type == 0:
current_next = (fig_data[0] & 0x80) >> 7
other_ensemble = (fig_data[0] & 0x40) >> 6
programme_data = (fig_data[0] & 0x20) >> 5
extension = fig_data[0] & 0x1f
type0_field = fig_data[1:]
if extension == 6:
self.process_fig_0_6(type0_field, fig_length - 1, programme_data)
elif extension == 9:
self.process_fig_0_9(type0_field)
elif extension == 10:
self.process_fig_0_10(type0_field)
i = i + 1 + fig_length
# Skip CRC
if i == fib_start + 30:
i = fib_start + 32
fib_start = i
def process_fig_0_6(self, data, data_size, pd):
i = 0
while i < data_size:
id_list_flag = (data[i] & 0x80) >> 7
link_actuator = (data[i] & 0x40) >> 6
soft_hard = (data[i] & 0x20) >> 5
international = (data[i] & 0x10) >> 4
link_set_number = ((data[i] & 0xf) << 8) | data[i+1]
i += 2
self.eti.check_linkset_actuator(link_set_number, soft_hard, link_actuator)
if id_list_flag:
if not pd:
identifier_list_qualifier = (data[i] & 0x60) >> 5
number_of_ids = data[i] & 0x0f
i += 1
id_list = []
for j in range(0, number_of_ids):
if not pd and not international:
id = "%X" % (data[i] << 8 | data[i+1])
id_list.append(id)
i += 2
elif not pd and international:
id = "%X" % (data[i] << 16 | data[i+1] << 8 | data[i+2])
id_list.append(id)
i += 3
elif pd:
sid = "%X" % (data[i] << 24 | data[i+1] << 16 | data[i+2] << 8 | data[i])
id_list.append(sid)
i += 4
if identifier_list_qualifier == 0: qualifier = "DAB"
elif identifier_list_qualifier == 1: qualifier = "FM"
elif identifier_list_qualifier == 2: qualifier = "AM"
else: qualifier = "DRM / AMSS"
self.eti.update_link_set_members(link_set_number, soft_hard, qualifier, id_list)
def process_fig_0_9(self, data):
ensemble_lto_direction = (data[0] & 0x20) >> 5 # 0 postive, 1 negative
ensemble_lto_value = data[0] & 0x1f
ensemble_lto_minutes = ensemble_lto_value * 30 * 60 # convert half hours to seconds
if not ensemble_lto_direction:
self.eti.lto = ensemble_lto_minutes
else:
self.eti.lto = 0 - ensemble_lto_minutes
def process_fig_0_10(self, data):
modified_julian_date = ((data[0] & 0x7f) << 10) | (data[1] << 2) | ((data[2] & 0xc0) >> 6)
(year, month, day) = self.mjd_to_ymd(modified_julian_date)
leap_second_indicator = data[2] & 2 >> 5
utc_flag = (data[2] & 0x08) >> 3
hours = ((data[2] & 0x07) << 2) | ((data[3] &0xc0) >> 6)
minutes = data[3] & 0x3f
if utc_flag == 0:
seconds = 0
miliseconds = 0
else:
self.time_long = True
seconds = (data[4] & 0xfc) >> 2
miliseconds = ((data[4] & 0x03) << 10) | data[5]
now = datetime(year, month, day, hours, minutes, seconds, miliseconds*1000)
if self.eti.lto:
now = now + timedelta(seconds = self.eti.lto)
self.eti.update_time(now)
def mjd_to_ymd(self, mjd):
# Adapted from http://www.csgnetwork.com/julianmodifdateconv.html
jd = math.floor(mjd) + 2400000.5
# Integer Julian day
jdi = math.floor (jd)
# Fractional part of day
jdf = jd - jdi + 0.5
# Really the next calendar day?
if jdf >= 1.0:
jdf = jdf - 1.0;
jdi = jdi + 1;
hour = jdf * 24.0
l = jdi + 68569
n = math.floor(4 * l / 146097)
l = math.floor (l) - math.floor ((146097 * n + 3) / 4)
year = math.floor (4000 * (l + 1) / 1461001)
l = l - (math.floor (1461 * year / 4)) + 31
month = math.floor (80 * l / 2447)
day = int(l - math.floor (2447 * month / 80))
l = math.floor (month / 11)
month = int(math.floor (month + 2 - 12 * l))
year = int(math.floor (100 * (n - 49) + year + l))
return (year, month, day)
def process(self):
print "Frame\tETI time\tBroadcast time\tEvent Details"
buffer = bytearray()
framebuffer = bytearray()
sync_found = False
while True:
try:
while buffer[1:4] != "\x07\x3A\xB6" and buffer[1:4] != "\xF8\xC5\x49":
if len(buffer) == 4:
buffer.pop(0)
byte = sys.stdin.read(1)
buffer.append(byte)
framebuffer.append(byte)
except Exception, e:
print "Error: %s" % e
raise
sys.exit(1)
if sync_found:
if len(framebuffer) > 4:
self.process_frame(framebuffer[:-4]) # Remove next frame's SYNC bytes
self.eti.increment_frame_count()
framebuffer = bytearray()
framebuffer.extend(buffer)
buffer = bytearray()
sync_found = True
eti_parser = Parser()
eti_parser.process()