2024-02-10 17:19:48 +00:00

301 lines
12 KiB
Python

import base64
import re
import shutil
import subprocess
from enum import Enum
from pathlib import Path
from typing import Any, Callable, Iterable, Optional, Union
from uuid import UUID
import requests
from langcodes import Language
from devine.core.constants import TERRITORY_MAP
from devine.core.drm import DRM_T
from devine.core.utilities import get_binary_path, get_boxes
from devine.core.utils.subprocess import ffprobe
class Track:
class DRM(Enum):
pass
class Descriptor(Enum):
URL = 1 # Direct URL, nothing fancy
M3U = 2 # https://en.wikipedia.org/wiki/M3U (and M3U8)
MPD = 3 # https://en.wikipedia.org/wiki/Dynamic_Adaptive_Streaming_over_HTTP
def __init__(
self,
id_: str,
url: Union[str, list[str]],
language: Union[Language, str],
is_original_lang: bool = False,
descriptor: Descriptor = Descriptor.URL,
needs_repack: bool = False,
drm: Optional[Iterable[DRM_T]] = None,
edition: Optional[str] = None,
extra: Optional[Any] = None
) -> None:
self.id = id_
self.url = url
# required basic metadata
self.language = Language.get(language)
self.is_original_lang = bool(is_original_lang)
# optional io metadata
self.descriptor = descriptor
self.needs_repack = bool(needs_repack)
# drm
self.drm = drm
# extra data
self.edition: str = edition
self.extra: Any = extra or {} # allow anything for extra, but default to a dict
# TODO: Currently using OnFoo event naming, change to just segment_filter
self.OnSegmentFilter: Optional[Callable] = None
# TODO: This should realistically be before decryption
# Called after the Track has been fully downloaded and decrypted
self.OnDownloaded: Optional[Callable] = None
# Called after the Track or a Segment has been decrypted
self.OnDecrypted: Optional[Callable] = None
# Called after the Track has been repackaged
self.OnRepacked: Optional[Callable] = None
# Called before the Track is multiplexed
self.OnMultiplex: Optional[Callable] = None
# should only be set internally
self.path: Optional[Path] = None
def __repr__(self) -> str:
return "{name}({items})".format(
name=self.__class__.__name__,
items=", ".join([f"{k}={repr(v)}" for k, v in self.__dict__.items()])
)
def __eq__(self, other: object) -> bool:
return isinstance(other, Track) and self.id == other.id
def get_track_name(self) -> Optional[str]:
"""Return the base Track Name. This may be enhanced in sub-classes."""
if (self.language.language or "").lower() == (self.language.territory or "").lower():
self.language.territory = None # e.g. en-en, de-DE
if self.language.territory == "US":
self.language.territory = None
reduced = self.language.simplify_script()
extra_parts = []
if reduced.script is not None:
extra_parts.append(reduced.script_name(max_distance=25))
if reduced.territory is not None:
territory = reduced.territory_name(max_distance=25)
extra_parts.append(TERRITORY_MAP.get(territory, territory))
return ", ".join(extra_parts) or None
def get_key_id(self, init_data: Optional[bytes] = None, *args, **kwargs) -> Optional[UUID]:
"""
Probe the DRM encryption Key ID (KID) for this specific track.
It currently supports finding the Key ID by probing the track's stream
with ffprobe for `enc_key_id` data, as well as for mp4 `tenc` (Track
Encryption) boxes.
It explicitly ignores PSSH information like the `PSSH` box, as the box
is likely to contain multiple Key IDs that may or may not be for this
specific track.
To retrieve the initialization segment, this method calls :meth:`get_init_segment`
with the positional and keyword arguments. The return value of `get_init_segment`
is then used to determine the Key ID.
Returns:
The Key ID as a UUID object, or None if the Key ID could not be determined.
"""
if not init_data:
init_data = self.get_init_segment(*args, **kwargs)
if not isinstance(init_data, bytes):
raise TypeError(f"Expected init_data to be bytes, not {init_data!r}")
# try get via ffprobe, needed for non mp4 data e.g. WEBM from Google Play
probe = ffprobe(init_data)
if probe:
for stream in probe.get("streams") or []:
enc_key_id = stream.get("tags", {}).get("enc_key_id")
if enc_key_id:
return UUID(bytes=base64.b64decode(enc_key_id))
# look for track encryption mp4 boxes
for tenc in get_boxes(init_data, b"tenc"):
if tenc.key_ID.int != 0:
return tenc.key_ID
# look for UUID mp4 boxes holding track encryption mp4 boxes
for uuid_box in get_boxes(init_data, b"uuid"):
if uuid_box.extended_type == UUID("8974dbce-7be7-4c51-84f9-7148f9882554"):
tenc = uuid_box.data
if tenc.key_ID.int != 0:
return tenc.key_ID
def get_init_segment(
self,
maximum_size: int = 20000,
url: Optional[str] = None,
byte_range: Optional[str] = None,
session: Optional[requests.Session] = None
) -> bytes:
"""
Get the Track's Initial Segment Data Stream.
HLS and DASH tracks must explicitly provide a URL to the init segment or file.
Providing the byte-range for the init segment is recommended where possible.
If `byte_range` is not set, it will make a HEAD request and check the size of
the file. If the size could not be determined, it will download up to the first
20KB only, which should contain the entirety of the init segment. You may
override this by changing the `maximum_size`.
The default maximum_size of 20000 (20KB) is a tried-and-tested value that
seems to work well across the board.
Parameters:
maximum_size: Size to assume as the content length if byte-range is not
used, the content size could not be determined, or the content size
is larger than it. A value of 20000 (20KB) or higher is recommended.
url: Explicit init map or file URL to probe from.
byte_range: Range of bytes to download from the explicit or implicit URL.
session: Session context, e.g., authorization and headers.
"""
if not session:
session = requests.Session()
if self.descriptor != self.Descriptor.URL and not url:
# We cannot know which init map from the HLS or DASH playlist is actually used.
# For DASH this could be from any adaptation set, any period, e.t.c.
# For HLS we could make some assumptions, but it's best that it is explicitly provided.
raise ValueError(
f"An explicit URL to an init map or file must be provided for {self.descriptor.name} tracks."
)
url = url or self.url
if not url:
raise ValueError("The track must have an URL to point towards it's data.")
content_length = maximum_size
if byte_range:
if not isinstance(byte_range, str):
raise TypeError(f"Expected byte_range to be a str, not {byte_range!r}")
if not re.match(r"^\d+-\d+$", byte_range):
raise ValueError(f"The value of byte_range is unrecognized: '{byte_range}'")
start, end = byte_range.split("-")
if start > end:
raise ValueError(f"The start range cannot be greater than the end range: {start}>{end}")
else:
size_test = session.head(url)
if "Content-Length" in size_test.headers:
content_length_header = int(size_test.headers["Content-Length"])
if content_length_header > 0:
# use whichever is smaller in case this is a large file
content_length = min(content_length_header, maximum_size)
range_test = session.head(url, headers={"Range": "bytes=0-1"})
if range_test.status_code == 206:
byte_range = f"0-{content_length-1}"
if byte_range:
res = session.get(
url=url,
headers={
"Range": f"bytes={byte_range}"
}
)
res.raise_for_status()
init_data = res.content
else:
# Take advantage of streaming support to take just the first n bytes
# This is a hacky alternative to HTTP's Range on unsupported servers
init_data = None
with session.get(url, stream=True) as s:
for chunk in s.iter_content(content_length):
init_data = chunk
break
if not init_data:
raise ValueError(f"Failed to read {content_length} bytes from the track URI.")
return init_data
def delete(self) -> None:
if self.path:
self.path.unlink()
self.path = None
def repackage(self) -> None:
if not self.path or not self.path.exists():
raise ValueError("Cannot repackage a Track that has not been downloaded.")
executable = get_binary_path("ffmpeg")
if not executable:
raise EnvironmentError("FFmpeg executable \"ffmpeg\" was not found but is required for this call.")
original_path = self.path
output_path = original_path.with_stem(f"{original_path.stem}_repack")
def _ffmpeg(extra_args: list[str] = None):
subprocess.run(
[
executable, "-hide_banner",
"-loglevel", "error",
"-i", original_path,
*(extra_args or []),
# Following are very important!
"-map_metadata", "-1", # don't transfer metadata to output file
"-fflags", "bitexact", # only have minimal tag data, reproducible mux
"-codec", "copy",
str(output_path)
],
check=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE
)
try:
_ffmpeg()
except subprocess.CalledProcessError as e:
if b"Malformed AAC bitstream detected" in e.stderr:
# e.g., TruTV's dodgy encodes
_ffmpeg(["-y", "-bsf:a", "aac_adtstoasc"])
else:
raise
self.swap(output_path)
self.move(original_path)
def move(self, target: Union[str, Path]) -> bool:
"""
Move the Track's file from current location, to target location.
This will overwrite anything at the target path.
"""
if not self.path:
return False
target = Path(target)
ok = Path(shutil.move(self.path, target)).resolve() == target.resolve()
if ok:
self.path = target
return ok
def swap(self, target: Union[str, Path]) -> bool:
"""
Swaps the Track's file with the Target file. The current Track's file is deleted.
Returns False if the Track is not yet downloaded, or the target path does not exist.
"""
target = Path(target)
if not target.exists() or not self.path:
return False
self.path.unlink()
ok = Path(shutil.move(target, self.path)).resolve() == self.path.resolve()
if not ok:
return False
return self.move(target)
__all__ = ("Track",)