Separate H264 specialized functions.
This commit is contained in:
Frédéric Tronel
@@ -0,0 +1,300 @@
|
||||
# SPDX-License-Identifier: GPL-2.0-or-later
|
||||
#
|
||||
# Copyright (C) 2026 Frédéric Tronel
|
||||
|
||||
""" All the following code is a transposition of documents:
|
||||
ISO/IEC H.264-201602
|
||||
ISO/IEC 14496-15
|
||||
"""
|
||||
|
||||
import logging
|
||||
from math import floor, log
|
||||
|
||||
from typeguard import typechecked
|
||||
import hexdump
|
||||
|
||||
|
||||
logger = logging.getLogger(__name__)
|
||||
|
||||
@typechecked
|
||||
def read_bit(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
"""
|
||||
Read a single bit from a byte buffer.
|
||||
|
||||
This function is part of the implementation of the H.264/AVC video compression standard,
|
||||
as specified in ISO/IEC H.264-201602 and ISO/IEC 14496-15.
|
||||
It takes a byte buffer and a bit position as input, and returns a tuple containing
|
||||
the updated bit position and the value of the bit at the specified position.
|
||||
|
||||
Args:
|
||||
buf (bytes): The byte buffer to read from.
|
||||
bit_position (int): The position of the bit to read, starting from 0.
|
||||
|
||||
Returns:
|
||||
tuple[int, int]: A tuple containing the updated bit position (bit_position + 1) and the
|
||||
value of the bit (0 or 1).
|
||||
"""
|
||||
byte_position = floor(floor(bit_position/8))
|
||||
byte = buf[byte_position]
|
||||
bit = (byte >> (7-(bit_position % 8))) & 1
|
||||
return bit_position+1, bit
|
||||
|
||||
@typechecked
|
||||
def read_boolean(buf:bytes, bit_position: int) -> tuple[int, bool]:
|
||||
"""
|
||||
Read a boolean value from a byte buffer.
|
||||
|
||||
This function reads a single bit from the byte buffer at the specified position and interprets
|
||||
it as a boolean value.
|
||||
It returns a tuple containing the updated bit position and the boolean value.
|
||||
|
||||
Args:
|
||||
buf (bytes): The byte buffer to read from.
|
||||
bit_position (int): The position of the bit to read, starting from 0.
|
||||
|
||||
Returns:
|
||||
tuple[int, bool]: A tuple containing the updated bit position and the boolean value
|
||||
(True if the bit is 1, False if the bit is 0).
|
||||
"""
|
||||
bit_position, b = read_bit(buf, bit_position)
|
||||
return bit_position, b==1
|
||||
|
||||
@typechecked
|
||||
def read_bits(buf:bytes, bit_position: int, nb_bits: int) -> tuple[int, int]:
|
||||
v = 0
|
||||
for _ in range(nb_bits):
|
||||
bit_position, bit = read_bit(buf, bit_position)
|
||||
v = v*2+bit
|
||||
return bit_position, v
|
||||
|
||||
@typechecked
|
||||
def read_byte(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, b = read_bits(buf, bit_position, 8)
|
||||
return bit_position, b
|
||||
|
||||
@typechecked
|
||||
def read_word(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, w = read_bits(buf, bit_position, 16)
|
||||
return bit_position, w
|
||||
|
||||
@typechecked
|
||||
def read_long(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, value = read_bits(buf, bit_position, 32)
|
||||
return bit_position, value
|
||||
|
||||
@typechecked
|
||||
def read_unsigned_exp_golomb(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
nb_zeroes=0
|
||||
while True:
|
||||
bit_position, b = read_bit(buf, bit_position)
|
||||
if b!=0:
|
||||
break
|
||||
nb_zeroes+=1
|
||||
|
||||
v1 = 1
|
||||
bit_position, v2 = read_bits(buf, bit_position, nb_zeroes)
|
||||
v = (v1<<nb_zeroes)+v2
|
||||
return bit_position, v-1
|
||||
|
||||
@typechecked
|
||||
def read_signed_exp_golomb(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, v = read_unsigned_exp_golomb(buf, bit_position)
|
||||
match v%2:
|
||||
case 0:
|
||||
return bit_position, -(v>>1)
|
||||
case 1:
|
||||
return bit_position, (v+1)>>1
|
||||
|
||||
@typechecked
|
||||
def write_bit(buf:bytes, bit_position: int, b) -> int:
|
||||
buf_length = len(buf)
|
||||
byte_position = floor(bit_position/8)
|
||||
|
||||
if byte_position >= buf_length:
|
||||
extension = bytearray(byte_position+1-buf_length)
|
||||
buf.extend(extension)
|
||||
|
||||
buf[byte_position] |= (b<<(7-(bit_position % 8)))
|
||||
bit_position+=1
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_boolean(buf:bytes, bit_position: int, b: bool) -> int:
|
||||
if b:
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
else:
|
||||
bit_position = write_bit(buf, bit_position, 0)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_bits(buf:bytes, bit_position: int, v, size) -> int:
|
||||
for i in range(size-1,-1,-1):
|
||||
b = (v>>i)&1
|
||||
bit_position = write_bit(buf, bit_position, b)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_byte(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 8)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_word(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 16)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_long(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 32)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_unsigned_exp_golomb(buf:bytes, bit_position: int, v) -> int:
|
||||
n = floor(log(v+1)/log(2))+1
|
||||
# Write zeroes
|
||||
bit_position = write_bits(buf, bit_position, 0, n-1)
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
bit_position = write_bits(buf, bit_position, v+1, n-1)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_signed_exp_golomb(buf:bytes, bit_position: int, v) -> int:
|
||||
if v <= 0:
|
||||
bit_position = write_unsigned_exp_golomb(buf, bit_position, -v*2)
|
||||
else:
|
||||
bit_position = write_unsigned_exp_golomb(buf, bit_position, v*2-1)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def parse_rbsp_trailing_bits(buf:bytes, bit_position: int) -> int:
|
||||
bit_position, one = read_bit(buf, bit_position)
|
||||
if one==0:
|
||||
raise ValueError(f'Stop bit should be equal to one. Read: {one:d}')
|
||||
while bit_position%8 != 0:
|
||||
bit_position, zero = read_bit(buf, bit_position)
|
||||
if zero==1:
|
||||
raise ValueError('Trailing bit should be equal to zero')
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_rbsp_trailing_bits(buf:bytes, bit_position: int) -> int:
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
while bit_position%8 != 0:
|
||||
bit_position = write_bit(buf, bit_position, 0)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def more_rbsp_data(buf:bytes, bit_position: int) -> bool:
|
||||
logger.debug('Is there more data in buffer of length: %d at bit position: %d',
|
||||
len(buf), bit_position)
|
||||
|
||||
byte_length = len(buf)
|
||||
bit_length = byte_length*8
|
||||
|
||||
# We are at the end of buffer
|
||||
if bit_position == bit_length:
|
||||
return False
|
||||
|
||||
found = False
|
||||
for i in range(bit_length-1,-1,-1):
|
||||
pos, b = read_bit(buf, i)
|
||||
if b == 1:
|
||||
found = True
|
||||
break
|
||||
|
||||
if not found:
|
||||
raise ValueError('Impossible to find trailing stop bit !')
|
||||
|
||||
# No more data
|
||||
if bit_position == pos:
|
||||
return False
|
||||
|
||||
return True
|
||||
|
||||
# Convert from RBSP (Raw Byte Sequence Payload) to SODB (String Of Data Bits)
|
||||
@typechecked
|
||||
def rbsp_to_sodb(buf:bytes) -> bytes:
|
||||
logger.debug('RBSP: %s', hexdump.dump(buf, sep=':'))
|
||||
|
||||
res = buf
|
||||
for b in [ b'\x00', b'\x01', b'\x02', b'\x03']:
|
||||
pattern = b'\x00\x00\x03'+b
|
||||
replacement = b'\x00\x00' + b
|
||||
res = res.replace(pattern, replacement)
|
||||
|
||||
logger.debug('SODB: %s', hexdump.dump(res, sep=':'))
|
||||
return res
|
||||
|
||||
# Reverse operation SODB to RBSP.
|
||||
@typechecked
|
||||
def sodb_to_rbsp(buf:bytes) -> bytes:
|
||||
logger.debug('SODB: %s', hexdump.dump(buf, sep=':'))
|
||||
|
||||
res = buf
|
||||
for b in [ b'\x03', b'\x00', b'\x01', b'\x02']:
|
||||
pattern = b'\x00\x00'+b
|
||||
replacement = b'\x00\x00\x03' + b
|
||||
res = res.replace(pattern, replacement)
|
||||
|
||||
logger.debug('RBSP: %s', hexdump.dump(res, sep=':'))
|
||||
return res
|
||||
|
||||
# Useful for SPS and PPS
|
||||
@typechecked
|
||||
def parse_scaling_list(buf:bytes, bit_position: int, size) -> tuple[int,list[int]]:
|
||||
res = []
|
||||
last_scale = 8
|
||||
next_scale = 8
|
||||
for _ in range(size):
|
||||
if next_scale != 0:
|
||||
bit_position, delta_scale = read_signed_exp_golomb(buf, bit_position)
|
||||
next_scale = (last_scale+delta_scale+256) % 256
|
||||
v = last_scale if next_scale==0 else next_scale
|
||||
res.append(v)
|
||||
last_scale = v
|
||||
|
||||
return bit_position,res
|
||||
|
||||
# TODO: test optimized version.
|
||||
# The ISO/IEC H.264-201602 seems to take into account the case where the end of the deltas list
|
||||
# is full of zeroes.
|
||||
@typechecked
|
||||
def write_scaling_list(buf:bytes, bit_position: int, size, matrix:list[int],
|
||||
optimized: bool = False) -> int:
|
||||
logger.debug('Dumping matrix: %s of size: %d, size parameter: %d.', matrix, len(matrix), size)
|
||||
|
||||
prev = 8
|
||||
deltas = []
|
||||
for i in range(size):
|
||||
v = matrix[i]
|
||||
delta = v - prev
|
||||
deltas.append(delta)
|
||||
prev = v
|
||||
|
||||
if not optimized:
|
||||
for delta in deltas:
|
||||
bit_position = write_signed_exp_golomb(buf, bit_position, delta)
|
||||
else:
|
||||
logger.error('Not yet implemented')
|
||||
exit(-1)
|
||||
# reverse = deltas.reverse()
|
||||
# compressed = False
|
||||
# while len(reverse)>0:
|
||||
# if reverse[0] == 0:
|
||||
# compressed = True
|
||||
# reverse.pop()
|
||||
# else:
|
||||
# break
|
||||
# deltas = reverse.reverse()
|
||||
# if compressed:
|
||||
# deltas.append(0)
|
||||
# for delta in deltas:
|
||||
# bit_position = write_signed_exp_golomb(buf, bit_position, delta)
|
||||
|
||||
return bit_position
|
||||
+29
-293
@@ -34,6 +34,32 @@ from iso639.exceptions import InvalidLanguageValue
|
||||
from tqdm import tqdm
|
||||
from typeguard import typechecked
|
||||
|
||||
from tscut.h264.bitstream import (
|
||||
read_bit,
|
||||
read_bits,
|
||||
read_boolean,
|
||||
read_byte,
|
||||
read_word,
|
||||
read_long,
|
||||
read_unsigned_exp_golomb,
|
||||
read_signed_exp_golomb,
|
||||
write_bit,
|
||||
write_boolean,
|
||||
write_bits,
|
||||
write_byte,
|
||||
write_word,
|
||||
write_long,
|
||||
write_unsigned_exp_golomb,
|
||||
write_signed_exp_golomb,
|
||||
parse_scaling_list,
|
||||
write_scaling_list,
|
||||
write_rbsp_trailing_bits,
|
||||
parse_rbsp_trailing_bits,
|
||||
sodb_to_rbsp,
|
||||
rbsp_to_sodb,
|
||||
more_rbsp_data
|
||||
)
|
||||
|
||||
# Local modules
|
||||
# TODO: create local modules for MP4, MKV
|
||||
|
||||
@@ -218,10 +244,9 @@ def get_frame_rate(ffprobe_path:str, input_file: IO[bytes]) -> float|None:
|
||||
return None
|
||||
if abs(frame_rate1*2 - frame_rate2) < 0.2:
|
||||
return frame_rate2/2
|
||||
else:
|
||||
logger.error('Video is interlaced and the disperancy between frame rates is too big:\
|
||||
%f / %f', frame_rate1, frame_rate2)
|
||||
return None
|
||||
logger.error('Video is interlaced and the disperancy between frame rates is too big:\
|
||||
%f / %f', frame_rate1, frame_rate2)
|
||||
return None
|
||||
|
||||
return frame_rate2
|
||||
|
||||
@@ -443,296 +468,7 @@ def get_codec_private_data_from_mkv(mkvinfo_path:str,
|
||||
return None, None
|
||||
|
||||
|
||||
# All the following code is a transposition of documents:
|
||||
# ISO/IEC H.264-201602
|
||||
# ISO/IEC 14496-15
|
||||
@typechecked
|
||||
def read_bit(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
"""
|
||||
Read a single bit from a byte buffer.
|
||||
|
||||
This function is part of the implementation of the H.264/AVC video compression standard,
|
||||
as specified in ISO/IEC H.264-201602 and ISO/IEC 14496-15.
|
||||
It takes a byte buffer and a bit position as input, and returns a tuple containing
|
||||
the updated bit position and the value of the bit at the specified position.
|
||||
|
||||
Args:
|
||||
buf (bytes): The byte buffer to read from.
|
||||
bit_position (int): The position of the bit to read, starting from 0.
|
||||
|
||||
Returns:
|
||||
tuple[int, int]: A tuple containing the updated bit position (bit_position + 1) and the
|
||||
value of the bit (0 or 1).
|
||||
"""
|
||||
byte_position = floor(floor(bit_position/8))
|
||||
byte = buf[byte_position]
|
||||
bit = (byte >> (7-(bit_position % 8))) & 1
|
||||
return bit_position+1, bit
|
||||
|
||||
@typechecked
|
||||
def read_boolean(buf:bytes, bit_position: int) -> tuple[int, bool]:
|
||||
"""
|
||||
Read a boolean value from a byte buffer.
|
||||
|
||||
This function reads a single bit from the byte buffer at the specified position and interprets
|
||||
it as a boolean value.
|
||||
It returns a tuple containing the updated bit position and the boolean value.
|
||||
|
||||
Args:
|
||||
buf (bytes): The byte buffer to read from.
|
||||
bit_position (int): The position of the bit to read, starting from 0.
|
||||
|
||||
Returns:
|
||||
tuple[int, bool]: A tuple containing the updated bit position and the boolean value
|
||||
(True if the bit is 1, False if the bit is 0).
|
||||
"""
|
||||
bit_position, b = read_bit(buf, bit_position)
|
||||
return bit_position, b==1
|
||||
|
||||
@typechecked
|
||||
def read_bits(buf:bytes, bit_position: int, nb_bits: int) -> tuple[int, int]:
|
||||
v = 0
|
||||
for _ in range(nb_bits):
|
||||
bit_position, bit = read_bit(buf, bit_position)
|
||||
v = v*2+bit
|
||||
return bit_position, v
|
||||
|
||||
@typechecked
|
||||
def read_byte(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, b = read_bits(buf, bit_position, 8)
|
||||
return bit_position, b
|
||||
|
||||
@typechecked
|
||||
def read_word(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, w = read_bits(buf, bit_position, 16)
|
||||
return bit_position, w
|
||||
|
||||
@typechecked
|
||||
def read_long(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, value = read_bits(buf, bit_position, 32)
|
||||
return bit_position, value
|
||||
|
||||
@typechecked
|
||||
def read_unsigned_exp_golomb(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
nb_zeroes=0
|
||||
while True:
|
||||
bit_position, b = read_bit(buf, bit_position)
|
||||
if b!=0:
|
||||
break
|
||||
nb_zeroes+=1
|
||||
|
||||
v1 = 1
|
||||
bit_position, v2 = read_bits(buf, bit_position, nb_zeroes)
|
||||
v = (v1<<nb_zeroes)+v2
|
||||
return bit_position, v-1
|
||||
|
||||
@typechecked
|
||||
def read_signed_exp_golomb(buf:bytes, bit_position: int) -> tuple[int, int]:
|
||||
bit_position, v = read_unsigned_exp_golomb(buf, bit_position)
|
||||
match v%2:
|
||||
case 0:
|
||||
return bit_position, -(v>>1)
|
||||
case 1:
|
||||
return bit_position, (v+1)>>1
|
||||
|
||||
@typechecked
|
||||
def write_bit(buf:bytes, bit_position: int, b) -> int:
|
||||
buf_length = len(buf)
|
||||
byte_position = floor(bit_position/8)
|
||||
|
||||
if byte_position >= buf_length:
|
||||
extension = bytearray(byte_position+1-buf_length)
|
||||
buf.extend(extension)
|
||||
|
||||
buf[byte_position] |= (b<<(7-(bit_position % 8)))
|
||||
bit_position+=1
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_boolean(buf:bytes, bit_position: int, b: bool) -> int:
|
||||
if b:
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
else:
|
||||
bit_position = write_bit(buf, bit_position, 0)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_bits(buf:bytes, bit_position: int, v, size) -> int:
|
||||
for i in range(size-1,-1,-1):
|
||||
b = (v>>i)&1
|
||||
bit_position = write_bit(buf, bit_position, b)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_byte(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 8)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_word(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 16)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_long(buf:bytes, bit_position: int, v) -> int:
|
||||
bit_position = write_bits(buf, bit_position, v, 32)
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_unsigned_exp_golomb(buf:bytes, bit_position: int, v) -> int:
|
||||
n = floor(log(v+1)/log(2))+1
|
||||
# Write zeroes
|
||||
bit_position = write_bits(buf, bit_position, 0, n-1)
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
bit_position = write_bits(buf, bit_position, v+1, n-1)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_signed_exp_golomb(buf:bytes, bit_position: int, v) -> int:
|
||||
if v <= 0:
|
||||
bit_position = write_unsigned_exp_golomb(buf, bit_position, -v*2)
|
||||
else:
|
||||
bit_position = write_unsigned_exp_golomb(buf, bit_position, v*2-1)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def parse_rbsp_trailing_bits(buf:bytes, bit_position: int) -> int:
|
||||
bit_position, one = read_bit(buf, bit_position)
|
||||
if one==0:
|
||||
raise ValueError(f'Stop bit should be equal to one. Read: {one:d}')
|
||||
while bit_position%8 != 0:
|
||||
bit_position, zero = read_bit(buf, bit_position)
|
||||
if zero==1:
|
||||
raise ValueError('Trailing bit should be equal to zero')
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def write_rbsp_trailing_bits(buf:bytes, bit_position: int) -> int:
|
||||
bit_position = write_bit(buf, bit_position, 1)
|
||||
while bit_position%8 != 0:
|
||||
bit_position = write_bit(buf, bit_position, 0)
|
||||
|
||||
return bit_position
|
||||
|
||||
@typechecked
|
||||
def more_rbsp_data(buf:bytes, bit_position: int) -> bool:
|
||||
logger = logging.getLogger(__name__)
|
||||
logger.debug('Is there more data in buffer of length: %d at bit position: %d',
|
||||
len(buf), bit_position)
|
||||
|
||||
byte_length = len(buf)
|
||||
bit_length = byte_length*8
|
||||
|
||||
# We are at the end of buffer
|
||||
if bit_position == bit_length:
|
||||
return False
|
||||
else:
|
||||
found = False
|
||||
for i in range(bit_length-1,-1,-1):
|
||||
pos, b = read_bit(buf, i)
|
||||
if b == 1:
|
||||
found = True
|
||||
break
|
||||
|
||||
if not found:
|
||||
raise ValueError('Impossible to find trailing stop bit !')
|
||||
|
||||
# No more data
|
||||
if bit_position == pos:
|
||||
return False
|
||||
|
||||
return True
|
||||
|
||||
# Convert from RBSP (Raw Byte Sequence Payload) to SODB (String Of Data Bits)
|
||||
@typechecked
|
||||
def rbsp_to_sodb(buf:bytes) -> bytes:
|
||||
logger = logging.getLogger(__name__)
|
||||
|
||||
logger.debug('RBSP: %s', hexdump.dump(buf, sep=':'))
|
||||
|
||||
res = buf
|
||||
for b in [ b'\x00', b'\x01', b'\x02', b'\x03']:
|
||||
pattern = b'\x00\x00\x03'+b
|
||||
replacement = b'\x00\x00' + b
|
||||
res = res.replace(pattern, replacement)
|
||||
|
||||
logger.debug('SODB: %s', hexdump.dump(res, sep=':'))
|
||||
return res
|
||||
|
||||
# Reverse operation SODB to RBSP.
|
||||
@typechecked
|
||||
def sodb_to_rbsp(buf:bytes) -> bytes:
|
||||
logger = logging.getLogger(__name__)
|
||||
logger.debug('SODB: %s', hexdump.dump(buf, sep=':'))
|
||||
|
||||
res = buf
|
||||
for b in [ b'\x03', b'\x00', b'\x01', b'\x02']:
|
||||
pattern = b'\x00\x00'+b
|
||||
replacement = b'\x00\x00\x03' + b
|
||||
res = res.replace(pattern, replacement)
|
||||
|
||||
logger.debug('RBSP: %s', hexdump.dump(res, sep=':'))
|
||||
return res
|
||||
|
||||
# Useful for SPS and PPS
|
||||
@typechecked
|
||||
def parse_scaling_list(buf:bytes, bit_position: int, size) -> tuple[int,list[int]]:
|
||||
res = []
|
||||
last_scale = 8
|
||||
next_scale = 8
|
||||
for _ in range(size):
|
||||
if next_scale != 0:
|
||||
bit_position, delta_scale = read_signed_exp_golomb(buf, bit_position)
|
||||
next_scale = (last_scale+delta_scale+256) % 256
|
||||
v = last_scale if next_scale==0 else next_scale
|
||||
res.append(v)
|
||||
last_scale = v
|
||||
|
||||
return bit_position,res
|
||||
|
||||
# TODO: test optimized version.
|
||||
# The ISO/IEC H.264-201602 seems to take into account the case where the end of the deltas list
|
||||
# is full of zeroes.
|
||||
@typechecked
|
||||
def write_scaling_list(buf:bytes, bit_position: int, size, matrix:list[int],
|
||||
optimized: bool = False) -> int:
|
||||
logger = logging.getLogger(__name__)
|
||||
logger.debug('Dumping matrix: %s of size: %d, size parameter: %d.', matrix, len(matrix), size)
|
||||
|
||||
prev = 8
|
||||
deltas = []
|
||||
for i in range(size):
|
||||
v = matrix[i]
|
||||
delta = v - prev
|
||||
deltas.append(delta)
|
||||
prev = v
|
||||
|
||||
if not optimized:
|
||||
for delta in deltas:
|
||||
bit_position = write_signed_exp_golomb(buf, bit_position, delta)
|
||||
else:
|
||||
logger.error('Not yet implemented')
|
||||
exit(-1)
|
||||
# reverse = deltas.reverse()
|
||||
# compressed = False
|
||||
# while len(reverse)>0:
|
||||
# if reverse[0] == 0:
|
||||
# compressed = True
|
||||
# reverse.pop()
|
||||
# else:
|
||||
# break
|
||||
# deltas = reverse.reverse()
|
||||
# if compressed:
|
||||
# deltas.append(0)
|
||||
# for delta in deltas:
|
||||
# bit_position = write_signed_exp_golomb(buf, bit_position, delta)
|
||||
|
||||
return bit_position
|
||||
|
||||
@dataclass
|
||||
class HRD:
|
||||
|
||||
Reference in New Issue
Block a user