Bit Slicer 9k
- Super fast bitslicing.
- bitshift speed without bitwise complexity.
Install
pip install bitslicer9kHelp(Slicer9k)
Help on class Slicer9k in module bitslicer9k:
class Slicer9k(builtins.object)
| Slicer9k(bites)
|
| Methods defined here:
|
| __init__(self, bites)
| From bytes to bits
|
| as90k(self, num_bits)
| return bitslice as 90k time
|
| asdecodedhex(self, num_bits)
| return decoded hex of a bitslice
|
| asflag(self, num_bits=1)
| returns one bit as True or False
|
| ashex(self, num_bits)
| return the hex value of a bitslice
|
| asint(self, num_bits)
| Starting at self.idx of self.bits, slice off num_bits of bits.
|
| ----------------------------------------------------------------------
I used to do this
from struct import unpack
sync,two_bytes,one_byte = unpack('>BHB', packet[:4])
tei = two_bytes >> 15
pusi = two_bytes >> 14 & 0x1
ts_priority = two_bytes >>13 & 0x1
pid = two_bytes & 0x1fff
scramble = one_byte >>6
afc = (one_byte & 48) >> 4
count = one_byte & 15Now I use bitslicer9k and do this
from bitslicer9k import Slicer9k
header= Slicer9k(packet[:4])
sync=header.asint(8)
tei=header.asflag(1)
pusi=header.asflag(1)
ts_priority=header.asflag(1)
pid=header.asint(13)
scramble=header.asint(2)
afc=header.asint(2)
count=header.asint(4)Example Usage
- Parse a SCTE 35 splice information section from a hex encoded string
>>> from bitslicer9k import Slicer9k
>>> bites= bytes.fromhex( 'FC302F000000000000FFFFF00506FEAEF17C4C0019021743554549480000077F9F0808000000002CA56C97110000C4876A2E')
>>> class Splice_Info_Section:
def __init__(self,bs):
self.table_id =bs.ashex(8)
self.section_syntax_indicator = bs.asflag(1)
self.private = bs.asflag(1)
self.reserved=bs.asint(2)
self.section_length = bs.asint(12)
self.protocol_version = bs.asint(8)
self.encrypted_packet = bs.asflag(1)
self.encryption_algorithm =bs.asint(6)
self.pts_adjustment = bs.as90k(33)
self.cw_index = bs.ashex(8)
self.tier = bs.ashex(12)
self.splice_command_length = bs.asint(12)
self.splice_command_type = bs.asint(8)
>>> bs=Slicer9k(bites)
>>> sps=Splice_Info_Section(bs)
>>> vars(sps)
{'table_id': '0xfc', 'section_syntax_indicator': False, 'private': False, 'reserved': 3, 'section_length': 47,
'protocol_version': 0, 'encrypted_packet': False, 'encryption_algorithm': 0, 'pts_adjustment': '0.000000',
'cw_index': '0xff', 'tier': '0xfff', 'splice_command_length': 5, 'splice_command_type': 6, 'descriptor_loop_length': 25}
>>>
