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LiberPrayground/other/761/mp3.py
relikd dbc709da07 761
2021-03-04 22:07:33 +01:00

363 lines
11 KiB
Python
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#!/usr/bin/env python3
import os
import sys
if len(sys.argv) > 1 and os.path.isfile(sys.argv[1]):
INPUT_FILE = sys.argv[1]
else:
INPUT_FILE = 'audio_files/761.MP3' # '761.MP3' 'index.mp3'
# print('File not found.')
# exit()
class MP3Header(object):
# https://id3.org/mp3Frame
# http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html
# http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm
# Starts with 11x 1-byte
SYNC = '' # 11 bit
ID = { # 2 bit (but reduced to 1 later)
0b00: 'MPEG Version 2.5',
0b01: 'reserved',
0b10: 'MPEG Version 2 (ISO/IEC 13818-3)',
0b11: 'MPEG Version 1 (ISO/IEC 11172-3)'}
LAYER = { # 2 bit (but -1 later)
0b00: 'reserved',
0b01: 'Layer III',
0b10: 'Layer II',
0b11: 'Layer I'}
PROTECTION = { # 1 bit
0: 'Protected', # 16bit CRC after header
1: 'Not Protected'}
BITRATE = { # 4 bit
# MPEG2-Layer3, M2-L2, M2-L1, M1-L3, M1-L2, M1-L1 in kbit/s
0b0000: [0, 0, 0, 0, 0, 0], # free
0b0001: [8000, 32000, 32000, 32000, 32000, 32000],
0b0010: [16000, 48000, 64000, 40000, 48000, 64000],
0b0011: [24000, 56000, 96000, 48000, 56000, 96000],
0b0100: [32000, 64000, 128000, 56000, 64000, 128000],
0b0101: [64000, 80000, 160000, 64000, 80000, 160000],
0b0110: [80000, 96000, 192000, 80000, 96000, 192000],
0b0111: [56000, 112000, 224000, 96000, 112000, 224000],
0b1000: [64000, 128000, 256000, 112000, 128000, 256000],
0b1001: [128000, 160000, 288000, 128000, 160000, 288000],
0b1010: [160000, 192000, 320000, 160000, 192000, 320000],
0b1011: [112000, 224000, 352000, 192000, 224000, 352000],
0b1100: [128000, 256000, 384000, 224000, 256000, 384000],
0b1101: [256000, 320000, 416000, 256000, 320000, 416000],
0b1110: [320000, 384000, 448000, 320000, 384000, 448000],
0b1111: [0, 0, 0, 0, 0, 0]} # bad
FREQUENCY = { # 2 bit in Hz
# MPEG-2, MPEG-1, MPEG-2.5 (not used)
0b00: [22050, 44100, 11025],
0b01: [24000, 48000, 12000],
0b10: [16000, 32000, 8000],
0b11: [0, 0, 0]} # reserved
PADDING = { # 1 bit
0: 'Padded', # +1 byte to frame length
1: 'Not Padded'}
PRIVATE = { # 1 bit
0: 'free', # freely used for whatever
1: 'free'}
MODE = { # 2 bit
0b00: 'Stereo',
0b01: 'Joint stereo (Stereo)',
0b10: 'Dual channel (2 mono channels)',
0b11: 'Single channel (Mono)'}
MODE_EXTENSION = { # 2 bit
# Layer I & II Layer III
# Intensity stereo MS stereo
# 0b00 bands 4 to 31 off off
# 0b01 bands 8 to 31 on off
# 0b10 bands 12 to 31 off on
# 0b11 bands 16 to 31 on on
}
COPYRIGHT = { # 1 bit
0: 'Not Copyrighted',
1: 'Copyrighted'}
ORIGINAL = { # 1 bit
0: 'Copy of Original',
1: 'Original'}
EMPHASIS = { # 2 bit
0b00: 'none',
0b01: '50/15 ms',
0b10: 'reserved',
0b11: 'CCIT J.17'}
MULTIPLY = [144, 144, 12] # frame length multiplier
# FRAMESIZE = [0, 1152, 1152, 384] # in samples
# SLOTS = [0, 1, 1, 4] # in bytes
def init_from_bytes(self, b0, b1, b2, b3):
self.emphasis = b3 & 0b11
b3 >>= 2
self.original = b3 & 1
b3 >>= 1
self.copyright = b3 & 1
b3 >>= 1
self.mode_extension = b3 & 0b11
b3 >>= 2
self.mode = b3 & 0b11
self.private = b2 & 1
b2 >>= 1
self.pad = b2 & 1
b2 >>= 1
self.frequency = b2 & 0b11
if self.frequency == 3:
raise ValueError('Reserved sample rate')
b2 >>= 2
self.bitrate = b2 & 0b1111
if self.frequency == 0b1111:
raise ValueError('Invalid bitrate')
self.protection = b1 & 1
b1 >>= 1
self.layer = b1 & 0b11 # Layer I-III
if self.layer == 0:
raise ValueError('Reserved MPEG-Layer')
b1 >>= 2
self.id = b1 & 0b11
b1 >>= 2
self.sync = (b0 << 3) + (b1 & 0b111)
if self.sync != 0b11111111111:
raise ValueError('Not a MP3 header')
def __init__(self, b0, b1, b2, b3):
self.init_from_bytes(b0, b1, b2, b3)
i_lyr = self.layer - 1 # because arrays
i_id = self.id & 1 # because arrays
br = self.BITRATE[self.bitrate][i_lyr + i_id * 3]
sr = self.FREQUENCY[self.frequency][i_id]
self.framelength = self.MULTIPLY[i_lyr] * br / sr
if self.pad:
self.framelength += 1
if i_lyr == 2: # LAYER-1
self.framelength *= 4
# TODO: check whether CRC length must be added
# if self.protection == 0:
self.framelength = int(self.framelength)
def as_bytes(self):
b = self.sync
b = b << 2 | self.id
b = b << 2 | self.layer
b = b << 1 | self.protection
b = b << 4 | self.bitrate
b = b << 2 | self.frequency
b = b << 1 | self.pad
b = b << 1 | self.private
b = b << 2 | self.mode
b = b << 2 | self.mode_extension
b = b << 1 | self.copyright
b = b << 1 | self.original
b = b << 2 | self.emphasis
return b.to_bytes(4, 'big')
def __str__(self):
f = '{:011b} {:02b} {:02b} {:b} {:04b} {:02b} {:b} {:b} {:02b} {:02b} {:b} {:b} {:02b}'
return f.format(
self.sync, self.id, self.layer, self.protection, self.bitrate,
self.frequency, self.pad, self.private, self.mode,
self.mode_extension, self.copyright, self.original, self.emphasis)
def bin_to_hex(binary_str):
ret = ''
for i in range(0, len(binary_str), 8):
ret += '{:02X}'.format(int(binary_str[i:i + 8], 2))
return ret
def bin_to_text(binary_str):
ret = ''
for i in range(0, len(binary_str), 8):
ret += chr(int(binary_str[i:i + 8], 2))
return ret
def flip_bits(bits):
return bits.replace('1', '_').replace('0', '1').replace('_', '0')
# def read_mp3_headers(bytes, to_file):
# with open(to_file, 'w') as fo:
# counter = 0
# offset = 0
# for byte in bytes:
# if offset < 6000: # skip ID3
# offset += 8
# continue
# for x in [128, 64, 32, 16, 8, 4, 2, 1]:
# offset += 1
# z = 1 if byte & x else 0
# if z:
# counter += 1
# else:
# if counter >= 13:
# fo.write('{}\n'.format(offset))
# counter = 0
# def prepare_mp3_headers(bytes, header_file):
# with open(header_file, 'r') as f:
# indices = [int(x) for x in f.readlines()]
# all_of_them = []
# for i in indices[:10]:
# i -= 14 # beginning of header, 13 + 1 for prev bit
# major = i // 8
# minor = i % 8
# raw_int = 0
# for u in range(5):
# raw_int += bytes[major + u] << (32 - u * 8)
# bit_str = ''
# for x in range(7 - minor + 32, 7 - minor, -1):
# bit_str += '1' if raw_int & (1 << x) else '0'
# try:
# all_of_them.append((i, MP3Header(bit_str)))
# except ValueError:
# pass
# return all_of_them
# def analyze_mp3_headers(bytes, prepared_obj):
# txt = ''
# for i, head in prepared_obj:
# print('{:06d} {} {}'.format(i, head, head.framelength))
# # if head == '00':
# # txt += head[7]
# print(txt)
# print(bin_to_text(txt))
# read_mp3_headers(bytes, to_file='mp3_header_indices.txt')
# anlz = prepare_mp3_headers(bytes, header_file='mp3_header_indices.txt')
# analyze_mp3_headers(bytes, anlz)
def parse_mp3_header(bytes):
for i, x in enumerate(bytes):
if x != 0xFF:
continue
if bytes[i + 1] >> 5 == 0b111:
try:
obj = MP3Header(*bytes[i:i + 4])
next_at = i + obj.framelength
except ValueError:
continue
try:
MP3Header(*bytes[next_at:next_at + 4])
return next_at, obj
except ValueError:
continue
def enum_mp3_header(bytes):
i, header = parse_mp3_header(bytes)
while header and i < len(bytes):
header = MP3Header(*bytes[i:i + 4])
yield i, header
i += header.framelength
with open(INPUT_FILE, 'rb') as f:
bytes = f.read()
uniq = [set(), set(), set(), set(), set(),
set(), set(), set(), set(), set(), set()]
keyz = ['id', 'layer', 'protection', 'frequency', 'pad', 'private',
'mode_extension', 'copyright', 'original', 'emphasis', 'framelength']
txt_chr = ''
txt_bit = ''
count_header = 0
# # Modify existing new file (a copy)
# last_i = 0
# with open(INPUT_FILE + '.modified.mp3', 'wb') as f:
# for i, header in enum_mp3_header(bytes):
# f.write(bytes[last_i:i])
# header.mode_extension = 3
# f.write(header.as_bytes())
# last_i = i + 4
# # Split in chunks
# if not os.path.isdir('tmp'):
# os.mkdir('tmp')
# if not os.path.isdir('tmp/mp3_frames'):
# os.mkdir('tmp/mp3_frames')
# last_i = 0
# running_i = 0
# for i, header in enum_mp3_header(bytes):
# with open('tmp/mp3_frames/{:06d}.mp3'.format(running_i), 'wb') as f:
# running_i += 1
# f.write(bytes[last_i:i])
# last_i = i
# exit()
txt = [''] * 624
# Parse and analyze header info
for i, header in enum_mp3_header(bytes):
# for x in range(1, 624):
# txt[x] += '1' if bytes[i - x] & 7 else '0'
# print(header)
count_header += 1
txt_chr += chr(bytes[i - 1])
txt_bit += '1' if bytes[i - 1] & 1 else '0'
for i, k in enumerate(keyz):
uniq[i].add(getattr(header, k))
for x in range(624):
if txt[x]:
print(bin_to_text(txt[x]))
# exit()
print('The unique values per header field:')
print({x: y for x, y in zip(keyz, uniq)})
print()
def print_bits(bits):
print('\nBinary:')
print(bits)
print('\nText (normal):')
print(bin_to_text(bits))
print('\nText (reverse):')
print(bin_to_text(bits[::-1]))
print('\nText (inverse):')
print(bin_to_text(flip_bits(bits)))
print('\nText (reverse, inverse):')
print(bin_to_text(flip_bits(bits[::-1])))
print()
print('Last byte per chunk:')
print(txt_chr)
print()
print('Last bit per chunk:')
print_bits(txt_bit)
# find header fields that differ
for i in range(len(uniq) - 1, -1, -1):
if len(uniq[i]) == 1:
del uniq[i]
del keyz[i]
else:
uniq[i] = uniq[i].pop() # good luck if there are three
if not uniq:
print('Nothing to do. No header changes value')
else:
txt = [''] * len(uniq)
# skip_once = True
for i, header in enum_mp3_header(bytes):
# if skip_once:
# skip_once = False
# continue
for i, k in enumerate(keyz):
txt[i] += '1' if getattr(header, k) == uniq[i] else '0'
for i, k in enumerate(keyz):
print('Header field:', k)
print_bits(txt[i])
print()
print('Number of headers: {}'.format(count_header))
print()
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