Initial commit: BiliDownloader Web 版：Python 零依赖后端 + shadcn/ui 前端
This commit is contained in:
WpyQwq
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# -*- coding: utf-8 -*-
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"""
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engine.py —— BiliDownloader 下载引擎（被 server.py 导入）
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这里的核心逻辑全部来自已经实测跑通的 bili_download.py，行为保持一致：
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* WBI 签名的站内搜索（老的无签名接口已被 B 站封禁）
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* 视频详情 / 分P / 清晰度列表（playurl qn=127 拿全部可用清晰度）
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* 多线程分段加速下载：Range 分片 + 并发 + 每片独立重试续传 + 旁路状态文件跨进程续传
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* ffmpeg 无损封装为 mp4
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只依赖 Python 标准库；ffmpeg 需在 PATH 或常见安装位置。
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"""
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from __future__ import annotations
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import hashlib
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import json
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import os
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import re
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import shutil
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import subprocess
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import threading
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import time
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import urllib.parse
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import urllib.request
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UA = ("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 "
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"(KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36")
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API_VIEW = "https://api.bilibili.com/x/web-interface/view?bvid={bvid}"
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API_NAV = "https://api.bilibili.com/x/web-interface/nav"
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API_SEARCH = "https://api.bilibili.com/x/web-interface/wbi/search/type"
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API_PLAYURL = ("https://api.bilibili.com/x/player/playurl?bvid={bvid}&cid={cid}"
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"&qn=127&fnver=0&fnval=4048&fourk=1")
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QN_NAME = {
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127: "8K 超高清", 126: "杜比视界", 125: "HDR 真彩", 120: "4K 超清",
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116: "1080P60", 112: "1080P 高码率", 80: "1080P 高清", 74: "720P60",
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64: "720P 高清", 32: "480P 清晰", 16: "360P 流畅", 6: "240P 极速",
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}
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# WBI 签名置换表（与 bilibili-API-collect 公开算法一致）
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MIXIN_KEY_ENC_TAB = [
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46, 47, 18, 2, 53, 8, 23, 32, 15, 50, 10, 31, 58, 3, 45, 35, 27, 43, 5, 49,
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33, 9, 42, 19, 29, 28, 14, 39, 12, 38, 41, 13, 37, 48, 7, 16, 24, 55, 40, 61,
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26, 17, 0, 1, 60, 51, 30, 4, 22, 25, 54, 21, 56, 59, 6, 63, 57, 62, 11, 36,
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20, 34, 44, 52,
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]
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CHUNK = 1 << 18 # 256KB
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SEG_MIN = 2 << 20 # 小于 2MB 不值得分片
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class BiliError(RuntimeError):
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"""带 B 站错误码的异常。"""
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def __init__(self, code: int, message: str):
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super().__init__(f"B 站接口错误 {code}: {message}")
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self.code = code
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self.message = message
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def human(n: float) -> str:
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for unit in ("B", "KB", "MB", "GB"):
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if n < 1024 or unit == "GB":
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return f"{n:.1f}{unit}" if unit != "B" else f"{int(n)}B"
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n /= 1024
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return f"{n:.1f}GB"
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# ------------------------------------------------------------------ HTTP
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def _headers(referer: str, cookie: str | None, extra: dict | None = None) -> dict:
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h = {"User-Agent": UA, "Referer": referer, "Accept": "*/*",
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"Accept-Encoding": "identity", "Connection": "keep-alive"}
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if cookie:
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h["Cookie"] = cookie
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if extra:
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h.update(extra)
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return h
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def _get(url: str, referer: str = "https://www.bilibili.com",
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cookie: str | None = None, timeout: int = 30) -> bytes:
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req = urllib.request.Request(url, headers=_headers(referer, cookie))
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with urllib.request.urlopen(req, timeout=timeout) as r:
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return r.read()
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def _api(url: str, cookie: str | None = None, referer: str = "https://www.bilibili.com") -> dict:
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raw = _get(url, referer, cookie)
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try:
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payload = json.loads(raw.decode("utf-8"))
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except Exception as exc:
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raise BiliError(-1, "B 站返回了非 JSON 内容（可能触发了风控）") from exc
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if payload.get("code") != 0:
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raise BiliError(payload.get("code", -1), payload.get("message", ""))
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return payload["data"]
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# ------------------------------------------------------------------ WBI 签名
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def _mixin_key(img_url: str, sub_url: str) -> str:
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img = os.path.basename(urllib.parse.urlparse(img_url).path).split(".")[0]
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sub = os.path.basename(urllib.parse.urlparse(sub_url).path).split(".")[0]
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raw = img + sub
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return "".join(raw[i] for i in MIXIN_KEY_ENC_TAB)[:32]
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def _sign(params: dict, mixin_key: str) -> str:
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params = dict(params)
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params["wts"] = int(time.time())
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items = sorted(params.items())
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query = urllib.parse.urlencode(
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[(k, "".join(c for c in str(v) if c not in "!'()*")) for k, v in items])
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w_rid = hashlib.md5((query + mixin_key).encode()).hexdigest()
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return f"{query}&w_rid={w_rid}"
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# ------------------------------------------------------------------ 业务接口
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def login_status(cookie: str | None) -> dict:
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"""未登录时 nav 返回 code=-101，但 data.wbi_img 仍然可用，所以这里不抛异常。"""
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try:
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raw = _get(API_NAV, cookie=cookie)
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payload = json.loads(raw.decode("utf-8"))
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except Exception as exc:
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return {"isLogin": False, "uname": "", "error": str(exc)}
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data = payload.get("data") or {}
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return {"isLogin": bool(data.get("isLogin")), "uname": data.get("uname") or "",
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"code": payload.get("code")}
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def search(keyword: str, page: int = 1, page_size: int = 20,
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cookie: str | None = None) -> dict:
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"""站内搜索。必须走 WBI 签名接口 —— 老的无签名接口已被封（返回非 JSON）。"""
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nav = json.loads(_get(API_NAV, cookie=cookie).decode("utf-8"))
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wbi = (nav.get("data") or {}).get("wbi_img") or {}
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img_url, sub_url = wbi.get("img_url"), wbi.get("sub_url")
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if not img_url or not sub_url:
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raise BiliError(-1, "无法获取 WBI 密钥")
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query = _sign({"search_type": "video", "keyword": keyword,
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"page": page, "page_size": page_size}, _mixin_key(img_url, sub_url))
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payload = json.loads(_get(f"{API_SEARCH}?{query}", cookie=cookie).decode("utf-8"))
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if payload.get("code") != 0:
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raise BiliError(payload.get("code", -1), payload.get("message", ""))
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data = payload.get("data") or {}
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results = []
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for item in (data.get("result") or []):
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title = re.sub(r"<em[^>]*>|</em>", "", item.get("title") or "")
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pic = item.get("pic") or ""
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if pic.startswith("//"):
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pic = "https:" + pic
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results.append({
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"bvid": item.get("bvid"),
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"title": title,
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"author": item.get("author"),
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"duration": item.get("duration"), # 字符串，如 "2:28"
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"play": item.get("play"),
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"danmaku": item.get("danmaku"),
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"pic": pic,
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"description": item.get("description") or item.get("desc") or "",
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})
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return {"items": results, "page": page,
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"numResults": data.get("numResults"),
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"hasMore": len(results) >= page_size}
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def video_detail(bvid: str, cookie: str | None = None) -> dict:
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data = _api(API_VIEW.format(bvid=bvid), cookie)
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pic = data.get("pic") or ""
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if pic.startswith("//"):
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pic = "https:" + pic
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return {
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"bvid": data.get("bvid"),
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"title": data.get("title"),
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"pic": pic,
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"duration": data.get("duration"), # int 秒
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"desc": data.get("desc") or "",
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"owner": (data.get("owner") or {}).get("name"),
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"stat": data.get("stat") or {},
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"pages": [{"cid": p.get("cid"), "page": p.get("page"),
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"part": p.get("part"), "duration": p.get("duration")}
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for p in (data.get("pages") or [])],
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}
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def play_url(bvid: str, cid: int, cookie: str | None = None) -> dict:
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"""qn=127 请求最高清晰度，让服务端把可用的清晰度都返回。
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★ 关键：清晰度列表必须按 `dash.video` 里**真正拿到的流**来建，不能用
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`accept_quality` / `support_formats` —— 那两个只反映视频"标称"支持什么，
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与当前账号能否下载无关。实测：未登录时 accept_quality 仍列出 120(4K)，
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但 dash.video 里只有 32(480P)。若按 accept_quality 建列表，用户会选到根本拿不到的清晰度，
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点下载才报错。
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"""
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data = _api(API_PLAYURL.format(bvid=bvid, cid=cid), cookie)
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accept = data.get("accept_quality") or []
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formats = {f.get("quality"): f for f in (data.get("support_formats") or [])}
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dash = data.get("dash") or {}
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videos = [{"quality": s.get("id"), "baseUrl": s.get("baseUrl"),
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"backupUrl": s.get("backupUrl") or [], "codecs": s.get("codecs") or "",
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"width": s.get("width"), "height": s.get("height"),
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"bandwidth": s.get("bandwidth")}
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for s in (dash.get("video") or []) if s.get("baseUrl")]
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audios = [{"baseUrl": s.get("baseUrl"), "backupUrl": s.get("backupUrl") or [],
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"codecs": s.get("codecs") or "", "bandwidth": s.get("bandwidth")}
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for s in (dash.get("audio") or []) if s.get("baseUrl")]
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# 同一清晰度可能有多种编码，取码率最高的一条来展示尺寸
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best: dict[int, dict] = {}
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for s in videos:
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q = s["quality"]
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if q is None:
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continue
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if q not in best or (s["bandwidth"] or 0) > (best[q]["bandwidth"] or 0):
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best[q] = s
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qualities = []
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for q in sorted(best, reverse=True):
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s = best[q]
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f = formats.get(q) or {}
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qualities.append({
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"quality": q,
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"label": f.get("new_description") or QN_NAME.get(q, str(q)),
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"width": s.get("width"), "height": s.get("height"),
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"codecs": s.get("codecs"),
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"bandwidth": s.get("bandwidth"),
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})
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return {"qualities": qualities, "video": videos, "audio": audios,
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# 实际可下载的最高清晰度（用它判断是否被"未登录"限制到 480P）
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"maxQuality": max(best) if best else 0,
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# 视频标称支持的清晰度，仅作参考展示
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"advertisedQuality": max(accept) if accept else 0,
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"duration": dash.get("duration") or 0}
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# ------------------------------------------------------------------ 下载
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def _state_path(dest: str) -> str:
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return dest + ".parts.json"
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def _resource_key(url: str) -> str:
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"""取 URL 中标识资源的稳定部分。
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baseUrl 带 e= 时效签名，重跑时签名字段与 CDN 域名都会变；只有 path
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（含 avid/cid/清晰度）保持不变，所以续传状态必须以 path 为键。
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"""
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return urllib.parse.urlparse(url).path
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def _load_state(dest: str, url: str, total: int, n: int) -> list[int]:
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if not os.path.exists(dest) or os.path.getsize(dest) != total:
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return [0] * n
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try:
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with open(_state_path(dest), "r", encoding="utf-8") as f:
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st = json.load(f)
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if st.get("key") != _resource_key(url) or st.get("total") != total:
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return [0] * n
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offs = [int(x) for x in st["offsets"]]
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if len(offs) != n:
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return [0] * n
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return [max(0, min(o, total)) for o in offs]
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except Exception:
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return [0] * n
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def _save_state(dest: str, url: str, total: int, offsets: list[int]) -> None:
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tmp = _state_path(dest) + ".tmp"
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try:
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with open(tmp, "w", encoding="utf-8") as f:
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json.dump({"key": _resource_key(url), "total": total, "offsets": offsets}, f)
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os.replace(tmp, _state_path(dest))
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except Exception:
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pass
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def probe(url: str, referer: str, cookie: str | None) -> tuple[int, bool]:
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"""探测总长度与是否支持 Range 分片。"""
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req = urllib.request.Request(
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url, headers=_headers(referer, cookie, {"Range": "bytes=0-0"}))
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with urllib.request.urlopen(req, timeout=30) as r:
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if r.status == 206:
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cr = r.headers.get("Content-Range", "")
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return (int(cr.split("/")[-1]) if "/" in cr else 0), True
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return int(r.headers.get("Content-Length") or 0), False
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def _download_range(url: str, fd, referer: str, cookie: str | None,
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start: int, end: int, on_bytes, cancel, retries: int = 24,
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on_chunk=None) -> None:
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cur = start
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attempt = 0
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while cur <= end:
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if cancel is not None and cancel.is_set():
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raise InterruptedError("已取消")
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try:
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req = urllib.request.Request(
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url, headers=_headers(referer, cookie, {"Range": f"bytes={cur}-{end}"}))
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with urllib.request.urlopen(req, timeout=45) as r:
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if r.status != 206:
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raise IOError(f"服务器未返回 206 (got {r.status})")
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os.lseek(fd, cur, os.SEEK_SET)
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while True:
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chunk = r.read(CHUNK)
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if not chunk:
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break
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os.write(fd, chunk)
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cur += len(chunk)
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on_bytes(len(chunk))
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if on_chunk:
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on_chunk(cur)
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if cur <= end:
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raise IOError("连接提前结束")
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attempt = 0
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except InterruptedError:
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raise
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except Exception as e:
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attempt += 1
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if attempt > retries:
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raise RuntimeError(f"分片重试 {retries} 次仍失败: {e}")
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time.sleep(min(0.5 * attempt, 5))
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def download_fast(url: str, dest: str, referer: str, cookie: str | None,
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threads: int = 16, on_progress=None, cancel=None,
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label: str = "视频") -> dict:
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"""多线程分段加速下载，支持跨进程断点续传。返回统计信息。"""
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total, ranges_ok = probe(url, referer, cookie)
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state = {"done": 0, "total": total, "t0": time.time(), "resumed": 0}
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def report():
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if not on_progress:
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return
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el = max(time.time() - state["t0"], 1e-6)
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on_progress({
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"label": label,
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"downloaded": state["done"],
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"total": total,
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"percent": (state["done"] * 100 / total) if total else 0,
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"speed": state["done"] / el,
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"threads": 1 if not ranges_ok else max(1, min(threads, 64)),
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"resumed": state["resumed"],
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})
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lock = threading.Lock()
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def on_bytes(n):
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with lock:
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state["done"] += n
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if not ranges_ok or total < SEG_MIN or threads <= 1:
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have = os.path.getsize(dest) if os.path.exists(dest) else 0
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if have and have < total:
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state["done"] = have
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state["resumed"] = have
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report()
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mode = "ab" if have else "wb"
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req_headers = _headers(referer, cookie,
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{"Range": f"bytes={have}-"} if have else None)
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with urllib.request.urlopen(urllib.request.Request(url, headers=req_headers),
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timeout=45) as r:
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if have and r.status != 206:
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have = 0
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mode = "wb"
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state["done"] = 0
|
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with open(dest, mode) as f:
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while True:
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||||
if cancel is not None and cancel.is_set():
|
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raise InterruptedError("已取消")
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chunk = r.read(CHUNK)
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||||
if not chunk:
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break
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f.write(chunk)
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on_bytes(len(chunk))
|
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report()
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||||
return {"total": total, "threads": 1, "resumed": state["resumed"]}
|
||||
|
||||
n = max(1, min(threads, 64))
|
||||
seg = total // n
|
||||
spans = [(i * seg, total - 1 if i == n - 1 else (i + 1) * seg - 1) for i in range(n)]
|
||||
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||||
offsets = _load_state(dest, url, total, n)
|
||||
if not os.path.exists(dest) or os.path.getsize(dest) != total:
|
||||
with open(dest, "wb") as f:
|
||||
f.truncate(total)
|
||||
offsets = [0] * n
|
||||
|
||||
resume_done = sum(offsets)
|
||||
if resume_done:
|
||||
state["done"] = resume_done
|
||||
state["resumed"] = resume_done
|
||||
report()
|
||||
|
||||
last_flush = [time.time()]
|
||||
errors: list[Exception] = []
|
||||
state_lock = threading.Lock()
|
||||
|
||||
def flush(force=False):
|
||||
with state_lock:
|
||||
now = time.time()
|
||||
if not force and now - last_flush[0] < 2.0:
|
||||
return
|
||||
last_flush[0] = now
|
||||
_save_state(dest, url, total, offsets)
|
||||
|
||||
def worker(i, s, e):
|
||||
try:
|
||||
fd = os.open(dest, os.O_RDWR | getattr(os, "O_BINARY", 0))
|
||||
try:
|
||||
def on_chunk(cur_abs, i=i, s=s):
|
||||
with state_lock:
|
||||
offsets[i] = cur_abs - s + 1
|
||||
flush()
|
||||
_download_range(url, fd, referer, cookie, s + offsets[i], e,
|
||||
on_bytes, cancel, on_chunk=on_chunk)
|
||||
finally:
|
||||
os.close(fd)
|
||||
with state_lock:
|
||||
offsets[i] = e - s + 1
|
||||
except InterruptedError as ex:
|
||||
errors.append(ex)
|
||||
except Exception as ex:
|
||||
errors.append(ex)
|
||||
|
||||
t0 = time.time()
|
||||
reporter_stop = threading.Event()
|
||||
|
||||
def reporter():
|
||||
while not reporter_stop.wait(0.4):
|
||||
report()
|
||||
|
||||
threading.Thread(target=reporter, daemon=True).start()
|
||||
|
||||
ts = [threading.Thread(target=worker, args=(i, s, e), daemon=True)
|
||||
for i, (s, e) in enumerate(spans)]
|
||||
for t in ts:
|
||||
t.start()
|
||||
for t in ts:
|
||||
t.join()
|
||||
reporter_stop.set()
|
||||
|
||||
if any(isinstance(e, InterruptedError) for e in errors):
|
||||
flush(force=True)
|
||||
raise InterruptedError("已取消")
|
||||
if errors:
|
||||
flush(force=True)
|
||||
raise RuntimeError(f"下载失败(进度已保存, 重跑可续传): {errors[0]}")
|
||||
|
||||
if os.path.getsize(dest) != total:
|
||||
raise RuntimeError(f"大小不符: {os.path.getsize(dest)} != {total}")
|
||||
if os.path.exists(_state_path(dest)):
|
||||
os.remove(_state_path(dest))
|
||||
|
||||
report()
|
||||
return {"total": total, "threads": n, "resumed": resume_done,
|
||||
"elapsed": time.time() - t0}
|
||||
|
||||
|
||||
# ------------------------------------------------------------------ ffmpeg
|
||||
|
||||
def find_ffmpeg() -> str | None:
|
||||
exe = shutil.which("ffmpeg")
|
||||
if exe:
|
||||
return exe
|
||||
for p in (r"C:\ffmpeg\bin\ffmpeg.exe",
|
||||
r"C:\Users\Administrator\miniconda3\Library\bin\ffmpeg.exe"):
|
||||
if os.path.exists(p):
|
||||
return p
|
||||
return None
|
||||
|
||||
|
||||
def merge(video: str, audio: str | None, out: str) -> None:
|
||||
ff = find_ffmpeg()
|
||||
if not ff:
|
||||
raise RuntimeError("找不到 ffmpeg")
|
||||
cmd = [ff, "-y", "-hide_banner", "-loglevel", "error", "-i", video]
|
||||
if audio:
|
||||
cmd += ["-i", audio, "-map", "0:v:0", "-map", "1:a:0", "-c", "copy"]
|
||||
else:
|
||||
cmd += ["-c", "copy"]
|
||||
cmd += ["-movflags", "+faststart", out]
|
||||
subprocess.run(cmd, check=True, creationflags=getattr(subprocess, "CREATE_NO_WINDOW", 0))
|
||||
|
||||
|
||||
# ------------------------------------------------------------------ 工具
|
||||
|
||||
def safe_name(name: str) -> str:
|
||||
name = re.sub(r'[\\/:*?"<>|\r\n\t]', "_", name).strip(" .")
|
||||
return (name or "video")[:120]
|
||||
|
||||
|
||||
def pick_streams(play: dict, quality: int, prefer_avc: bool = True):
|
||||
"""在指定清晰度下选码流：优先 H.264（兼容性最好），音频取码率最大。"""
|
||||
pool = [s for s in play["video"] if s["quality"] == quality]
|
||||
if not pool:
|
||||
return None, None
|
||||
if prefer_avc:
|
||||
avc = [s for s in pool if s["codecs"].startswith(("avc", "av01"))]
|
||||
pool = avc or pool
|
||||
video = max(pool, key=lambda s: s["bandwidth"])
|
||||
if not play["audio"]:
|
||||
return video, None
|
||||
audio = max(play["audio"], key=lambda s: s["bandwidth"])
|
||||
return video, audio
|
||||
Reference in New Issue
Block a user