totts.py(MPEG2-TSの中のTDTパケットを取り出して、中に入ってる時刻情報を表示するやつ)のリアルタイムストリーム入力可能にしたバージョン。

totts_stream.py

#! /usr/bin/env python3
#coding:utf-8

#require bitstring
import bitstring
from sys import argv
import math
import sys
import io
import time

#filename = argv[1]
packet_length = 188
#packet_length = 204
syncbyte = 0x47

count = 0
failcount = 0
summary = {}
first = True
readpos = 0

bio = io.BytesIO()

#quoted from https://gist.github.com/jiffyclub/1294443
def mjd_to_date(mjd):
    jd = mjd + 2400000.5
    jd = jd + 0.5
    F, I = math.modf(jd)
    I = int(I)
    A = math.trunc((I - 1867216.25)/36524.25)
    if I > 2299160:
        B = I + 1 + A - math.trunc(A / 4.)
    else:
        B = I
    C = B + 1524
    D = math.trunc((C - 122.1) / 365.25)
    E = math.trunc(365.25 * D)
    G = math.trunc((C - E) / 30.6001)
    day = int(C - E + F - math.trunc(30.6001 * G))
    if G < 13.5:
        month = G - 1
    else:
        month = G - 13
    if month > 2.5:
        year = D - 4716
    else:
        year = D - 4715

    return year, month, day

class TS:
    def __init__(self, packet):
        self.packet = packet
    
    def unpack(self):
        try:
            self.underflow = False
            if packet_length == 188:
                #188-5(header+pointer)-4(CRC)=179, 179*8=1432bits
                self.sync, self.error, self.pid, self.scramble, self.counter, self.pointer, self.payload, self.crc = \
                    self.packet.unpack('uint:8, bool, pad:2, uint:13, bits:2, pad:2, uint:4, uint:8, bits:1432, bytes:4')
            else:
                #TODO long packet
                pass
            
            #find sync
            if self.sync != syncbyte:
                found = self.packet.find('0x47', bytealigned=True) #findには文字列で渡す…
                return True
            
            return False
        except bitstring.ReadError:
            #バッファ枯渇
            self.underflow = True
            return True
    
    def tdt_unpack(self):
        table_id, mjd16, h1, h2, m1, m2, s1, s2 = \
            self.payload.unpack('uint:8, pad:16, uint:16, uint:4, uint:4, uint:4, uint:4, uint:4, uint:4')
        year, month, day = mjd_to_date(mjd16)
        hour = int(str(h1)+str(h2))
        minute = int(str(m1)+str(m2))
        sec = int(str(s1)+str(s2))
        print('TIME {}-{}-{} {}:{}:{} JST'.format(year, month, day, hour, minute, sec))
        

while True:
    #新規パケットをwriteする前に終端にseek(seek位置から書くから)
    bio.seek(0, io.SEEK_END)
    bio.write(sys.stdin.buffer.read(packet_length))
    #読むので前回位置にseek
    bio.seek(readpos)
    read_data = bio.read(packet_length)
    #前回seek位置を次のに合わせる
    readpos += packet_length
    
    packet = bitstring.ConstBitStream(bytes=read_data)
        
    ts = TS(packet)
    if ts.unpack():
        if not ts.underflow:
            #syncできなかったら戻る
            if ts.packet.bytepos != 0: #このパケット内にsyncがあったら
                readpos = readpos - packet_length + ts.packet.bytepos
                #print(ts.packet.bytepos)
        else:
            print('underflow')
            readpos -= packet_length
            if readpos < 0:
                readpos = 0
        failcount += 1
    
    else:
        #カウンタチェック
        #if not first:
        #    print('PID:{}  {}'.format(ts.pid, ts.counter))
        #TDT
        if ts.pid == 0x14 and not ts.error:
            ts.tdt_unpack()

        if not ts.error:
            try:
                summary[ts.pid] += 1
            except KeyError:
                summary[ts.pid] = 1
        
    first = False
    count += 1

print('-------------------------------')
print('PID count:',len(summary))
print('Fail:', failcount)
print('Total:', count)