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mold mp4_parser into mp4direct

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Lesmiscore 2022-07-14 12:15:43 +09:00
parent 2ed0b5568e
commit 302b23a9a3
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GPG key ID: 0EC2B52CF86236FF
2 changed files with 155 additions and 166 deletions
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157
yt_dlp/mp4_parser.py
View file

@ -1,157 +0,0 @@
import struct
from typing import Tuple
from io import BytesIO, RawIOBase
class LengthLimiter(RawIOBase):
"""
A bytes IO to limit length to be read.
"""
def __init__(self, r: RawIOBase, size: int):
self.r = r
self.remaining = size
def read(self, sz: int = None) -> bytes:
if self.remaining == 0:
return b''
if sz in (-1, None):
sz = self.remaining
sz = min(sz, self.remaining)
ret = self.r.read(sz)
if ret:
self.remaining -= len(ret)
return ret
def readall(self) -> bytes:
if self.remaining == 0:
return b''
ret = self.read(self.remaining)
if ret:
self.remaining -= len(ret)
return ret
def readable(self) -> bool:
return bool(self.remaining)
def read_harder(r, size):
"""
Try to read from the stream.
@params r byte stream to read
@params size Number of bytes to read in total
"""
retry = 0
buf = b''
while len(buf) < size and retry < 3:
ret = r.read(size - len(buf))
if not ret:
retry += 1
continue
retry = 0
buf += ret
return buf
def pack_be32(value: int) -> bytes:
""" Pack value to 4-byte-long bytes in the big-endian byte order """
return struct.pack('>I', value)
def pack_be64(value: int) -> bytes:
""" Pack value to 8-byte-long bytes in the big-endian byte order """
return struct.pack('>L', value)
def unpack_be32(value: bytes) -> int:
""" Convert 4-byte-long bytes in the big-endian byte order, to an integer value """
return struct.unpack('>I', value)[0]
def unpack_be64(value: bytes) -> int:
""" Convert 8-byte-long bytes in the big-endian byte order, to an integer value """
return struct.unpack('>L', value)[0]
def unpack_ver_flags(value: bytes) -> Tuple[int, int]:
"""
Unpack 4-byte-long value into version and flags.
@returns (version, flags)
"""
ver, up_flag, down_flag = struct.unpack('>BBH', value)
return ver, (up_flag << 16 | down_flag)
# https://github.com/gpac/mp4box.js/blob/4e1bc23724d2603754971abc00c2bd5aede7be60/src/box.js#L13-L40
MP4_CONTAINER_BOXES = ('moov', 'trak', 'edts', 'mdia', 'minf', 'dinf', 'stbl', 'mvex', 'moof', 'traf', 'vttc', 'tref', 'iref', 'mfra', 'meco', 'hnti', 'hinf', 'strk', 'strd', 'sinf', 'rinf', 'schi', 'trgr', 'udta', 'iprp', 'ipco')
""" List of boxes that nests the other boxes """
def parse_mp4_boxes(r: RawIOBase):
"""
Parses an ISO BMFF (which MP4 follows) and yields its boxes as a sequence.
This does not interpret content of these boxes.
Sequence details:
('atom', b'blablabla'): A box, with content (not container boxes)
('atom', b''): Possibly container box (must check MP4_CONTAINER_BOXES) or really an empty box
(None, 'atom'): End of a container box
Example: Path:
('test', b'123456') /test
('moov', b'') /moov (start of container box)
('helo', b'abcdef') /moov/helo
('1984', b'1q84') /moov/1984
('trak', b'') /moov/trak (start of container box)
('keys', b'2022') /moov/trak/keys
(None , 'trak') /moov/trak (end of container box)
('topp', b'1991') /moov/topp
(None , 'moov') /moov (end of container box)
"""
while True:
size_b = read_harder(r, 4)
if not size_b:
break
type_b = r.read(4)
# 00 00 00 20 is big-endian
box_size = unpack_be32(size_b)
type_s = type_b.decode()
if type_s in MP4_CONTAINER_BOXES:
yield (type_s, b'')
yield from parse_mp4_boxes(LengthLimiter(r, box_size - 8))
yield (None, type_s)
continue
# subtract by 8
full_body = read_harder(r, box_size - 8)
yield (type_s, full_body)
def write_mp4_boxes(w: RawIOBase, box_iter):
"""
Writes an ISO BMFF file from a given sequence to a given writer.
The iterator to be passed must follow parse_mp4_boxes's protocol.
"""
stack = [
(None, w), # parent box, IO
]
for btype, content in box_iter:
if btype in MP4_CONTAINER_BOXES:
bio = BytesIO()
stack.append((btype, bio))
continue
elif btype is None:
assert stack[-1][0] == content
btype, bio = stack.pop()
content = bio.getvalue()
wt = stack[-1][1]
wt.write(pack_be32(len(content) + 8))
wt.write(btype.encode()[:4])
wt.write(content)

164
yt_dlp/postprocessor/mp4direct.py
View file

@ -1,19 +1,165 @@
import os import os
import struct
from io import BytesIO, RawIOBase
from math import inf from math import inf
from typing import Tuple
from .common import PostProcessor from .common import PostProcessor
from ..utils import prepend_extension from ..utils import prepend_extension
from ..mp4_parser import (
write_mp4_boxes, class LengthLimiter(RawIOBase):
parse_mp4_boxes, """
pack_be32, A bytes IO to limit length to be read.
pack_be64, """
unpack_ver_flags,
unpack_be32, def __init__(self, r: RawIOBase, size: int):
unpack_be64, self.r = r
) self.remaining = size
def read(self, sz: int = None) -> bytes:
if self.remaining == 0:
return b''
if sz in (-1, None):
sz = self.remaining
sz = min(sz, self.remaining)
ret = self.r.read(sz)
if ret:
self.remaining -= len(ret)
return ret
def readall(self) -> bytes:
if self.remaining == 0:
return b''
ret = self.read(self.remaining)
if ret:
self.remaining -= len(ret)
return ret
def readable(self) -> bool:
return bool(self.remaining)
def read_harder(r, size):
"""
Try to read from the stream.
@params r byte stream to read
@params size Number of bytes to read in total
"""
retry = 0
buf = b''
while len(buf) < size and retry < 3:
ret = r.read(size - len(buf))
if not ret:
retry += 1
continue
retry = 0
buf += ret
return buf
def pack_be32(value: int) -> bytes:
""" Pack value to 4-byte-long bytes in the big-endian byte order """
return struct.pack('>I', value)
def pack_be64(value: int) -> bytes:
""" Pack value to 8-byte-long bytes in the big-endian byte order """
return struct.pack('>L', value)
def unpack_be32(value: bytes) -> int:
""" Convert 4-byte-long bytes in the big-endian byte order, to an integer value """
return struct.unpack('>I', value)[0]
def unpack_be64(value: bytes) -> int:
""" Convert 8-byte-long bytes in the big-endian byte order, to an integer value """
return struct.unpack('>L', value)[0]
def unpack_ver_flags(value: bytes) -> Tuple[int, int]:
"""
Unpack 4-byte-long value into version and flags.
@returns (version, flags)
"""
ver, up_flag, down_flag = struct.unpack('>BBH', value)
return ver, (up_flag << 16 | down_flag)
# https://github.com/gpac/mp4box.js/blob/4e1bc23724d2603754971abc00c2bd5aede7be60/src/box.js#L13-L40
MP4_CONTAINER_BOXES = ('moov', 'trak', 'edts', 'mdia', 'minf', 'dinf', 'stbl', 'mvex', 'moof', 'traf', 'vttc', 'tref', 'iref', 'mfra', 'meco', 'hnti', 'hinf', 'strk', 'strd', 'sinf', 'rinf', 'schi', 'trgr', 'udta', 'iprp', 'ipco')
""" List of boxes that nests the other boxes """
def parse_mp4_boxes(r: RawIOBase):
"""
Parses an ISO BMFF (which MP4 follows) and yields its boxes as a sequence.
This does not interpret content of these boxes.
Sequence details:
('atom', b'blablabla'): A box, with content (not container boxes)
('atom', b''): Possibly container box (must check MP4_CONTAINER_BOXES) or really an empty box
(None, 'atom'): End of a container box
Example: Path:
('test', b'123456') /test
('moov', b'') /moov (start of container box)
('helo', b'abcdef') /moov/helo
('1984', b'1q84') /moov/1984
('trak', b'') /moov/trak (start of container box)
('keys', b'2022') /moov/trak/keys
(None , 'trak') /moov/trak (end of container box)
('topp', b'1991') /moov/topp
(None , 'moov') /moov (end of container box)
"""
while True:
size_b = read_harder(r, 4)
if not size_b:
break
type_b = r.read(4)
# 00 00 00 20 is big-endian
box_size = unpack_be32(size_b)
type_s = type_b.decode()
if type_s in MP4_CONTAINER_BOXES:
yield (type_s, b'')
yield from parse_mp4_boxes(LengthLimiter(r, box_size - 8))
yield (None, type_s)
continue
# subtract by 8
full_body = read_harder(r, box_size - 8)
yield (type_s, full_body)
def write_mp4_boxes(w: RawIOBase, box_iter):
"""
Writes an ISO BMFF file from a given sequence to a given writer.
The iterator to be passed must follow parse_mp4_boxes's protocol.
"""
stack = [
(None, w), # parent box, IO
]
for btype, content in box_iter:
if btype in MP4_CONTAINER_BOXES:
bio = BytesIO()
stack.append((btype, bio))
continue
elif btype is None:
assert stack[-1][0] == content
btype, bio = stack.pop()
content = bio.getvalue()
wt = stack[-1][1]
wt.write(pack_be32(len(content) + 8))
wt.write(btype.encode()[:4])
wt.write(content)
class MP4FixupTimestampPP(PostProcessor): class MP4FixupTimestampPP(PostProcessor):