code :Transport Stream continuity check - 3

print all pid packet number and the not-continue packe number

from struct import *

tsfile = open('src.trp','rb')
if tsfile == None:
print 'open file fail'
tsstring = tsfile.read()
print 'read file ok'
tsdata = unpack(repr(len(tsstring))+'B',tsstring)
print 'convert OK, size = %d' % len(tsdata)

i=0
while tsdata[i] != 0x47:
i += 1
print 'found 1st sync: %d' % i


pidcount={}
discount={}
contp = {}
while i < len(tsdata)-188:
pid = ( tsdata[i+1]<< 8 | tsdata[i+2] ) & 0x1FFF
cont = tsdata[i+3] & 0x0F
if pid in contp.keys():
# print '%04X : %02X' % (pid,cont)
if cont != ((contp[pid]+1)&0xF):
if cont != 0 or contp[pid] != 0:
print 'not cont: %04X : %02x %02x' % (pid,contp[pid],cont)
discount[pid] += 1
contp[pid] = cont
pidcount[pid] += 1
else:
contp.update({pid:cont})
pidcount.update({pid:1})
discount.update({pid:0})
i += 188

# print out not cont number
allpid = contp.keys()
allpid.sort()

for ele in allpid:
print 'pid: %04X packet count : %7d, not continue: %d' % (ele,pidcount[ele],discount[ele])


code :Transport Stream continuity check - 2

承上篇：計算每一個 pid 的數量

from struct import *

# read in all data and convert to unsigned char
tsfile = open('logOsv17.trp','rb')
if tsfile == None:
print "Error opening logOsv17.trp to read"
tsstring = tsfile.read()
print "the size is : %d" % len(tsstring)

tsdata = unpack(repr(len(tsstring))+'B',tsstring)
print "%02x %02x %02x" % (tsdata[0],tsdata[1],tsdata[2])


# locate the 1st sync
i=0
while tsdata[0] != 0x47:
i += 1
print "found 1st 0x47: %d %02x" % (i,tsdata[i+188])

# start accumlate
pidtable = {} # pid : packet numbers
while i < len(tsdata)-188:
pid = tsdata[i+1]<<8 | tsdata[i+2]
pid = pid & 0x1FFF
# print "%02x %02x (%04x) - %02x" % (tsdata[i+1],tsdata[i+2],pid,tsdata[i+3]&0x0F)

if pid not in pidtable:
pidtable.update({pid:0})
else:
pidtable[pid] += 1

# find next packet sync
if tsdata[i+188] != 0x47:
print "%d : %02x" % (i,tsdata[i+188])
i+=1
while tsdata[i] != 0x47:
i += 1
else:
i += 188

# print results
allpid = pidtable.keys()
allpid.sort()
for i in allpid:
print "%04x : %d" % (i,pidtable[i])



code :Transport Stream continuity check

今天的進度： 找出所有的 pid

from struct import *

tsfile = open('logOsv17.trp','rb')
if tsfile == None:
print "Error opening logOsv17.trp to read"
tsstring = tsfile.read()
print "the size is : %d" % len(tsstring)

tsdata = unpack(repr(len(tsstring))+'B',tsstring)
print "%02x %02x %02x" % (tsdata[0],tsdata[1],tsdata[2])


prev0x47=0
i=0
while tsdata[0] != 0x47:
i += 1
print "found 1st 0x47: %d %02x" % (i,tsdata[i+188])

pidtable = []
while i < len(tsdata)-188:
pid = tsdata[i+1]<<8 | tsdata[i+2]
pid = pid & 0x1FFF
# print "%02x %02x (%04x) - %02x" % (tsdata[i+1],tsdata[i+2],pid,tsdata[i+3]&0x0F)
if pid not in pidtable:
pidtable.append(pid)

if tsdata[i+188] != 0x47:
print "%d : %02x" % (i,tsdata[i+188])
i+=1
while tsdata[i] != 0x47:
i += 1
else:
i += 188
pidtable.sort()
for i in pidtable:
print "%04x" % i


read binary file and convert to binary tuple

因為 file.read( ) 的傳回值是 string。所以沒辦法用 %X 印出。
也沒辦法用數值比較(?)。

所以讀進來後，要用 struct.unpack( )把 string 解譯為 binary。

unpack 的用法是：

unpack(fmt,string)

fmt 格式字串
string 要被轉換的 string

要一個一個 byte 的轉為 unsigned char ，要用 'B'。
'B' 前面還要指定總共要轉幾個 byte。
又，unpack 傳回的是 tuple，所以一次把所有的 string 轉成一個 unsigned char tunple，
要先寫好 fmt:

fmtstring = repr(len(readstring)) + 'B'

然後再轉：

data = unpack(fmtstring,readstring)

也可以寫在一起：

data = unpack(repr(len(readstring))+'B',readstring)