LangChain支持哔哩哔哩视频总结

是基于LangChain框架下的开发，所以最开始请先

pip install Langchain
pip install bilibili-api-python

技术要点：

1. 使用Langchain框架自带的Document loaders

2. 修改BiliBiliLoader的源码，自带的并不支持当前b站的视频加载

源码文件修改：

import json
import re
import warnings
from typing import List, Tuple
 
import requests
from langchain_core.documents import Document
from bilibili_api import sync, video
from langchain_community.document_loaders.base import BaseLoader
# Pre-compile regular expressions for video ID extraction
BV_PATTERN = re.compile(r"BV\w+")
AV_PATTERN = re.compile(r"av[0-9]+")
 
class BiliBiliLoader(BaseLoader):
    """
    Loader for fetching transcripts from BiliBili videos.
    """
 
    def __init__(self, video_urls: List[str], sessdata: str, bili_jct: str, buvid3: str):
        """Initialize with bilibili url.
        Args:
             video_urls (List[str]): List of BiliBili video URLs.
            sessdata (str): SESSDATA cookie value for authentication.
            bili_jct (str): BILI_JCT cookie value for authentication.
            buvid3 (str): BUVI3 cookie value for authentication.
        """
        self.video_urls = video_urls
        self.credential = video.Credential(
            sessdata=sessdata, bili_jct=bili_jct, buvid3=buvid3
        )
 
    def load(self) -> List[Document]:
        """
        Load and return a list of documents containing video transcripts.
        Returns:
            List[Document]: List of Document objects transcripts and metadata.
        """
        results = []
        for url in self.video_urls:
            transcript, video_info = self._get_bilibili_subs_and_info(url)
            doc = Document(page_content=transcript, metadata=video_info)
            results.append(doc)
        return results
 
    def _get_bilibili_subs_and_info(self, url: str) -> Tuple[str, dict]:
        """
              Retrieve video information and transcript for a given BiliBili URL.
        Args:
            url (str): BiliBili video URL.
        Returns:
            Tuple[str, dict]: A tuple containing the transcript and video information.
        """
        bvid = BV_PATTERN.search(url)
        if bvid:
            v = video.Video(bvid=bvid.group(), credential=self.credential)
        else:
            aid = AV_PATTERN.search(url)
            if aid:
                v = video.Video(aid=int(aid.group()[2:]), credential=self.credential)
            else:
                raise ValueError(f"Unable to find a valid video ID in URL: {url}")
 
        video_info = sync(v.get_info())
        video_info.update({"url": url})
        sub = sync(v.get_subtitle(video_info["cid"]))
 
        # Retrieve and process subtitle content
        sub_list = sub["subtitles"]
        if sub_list:
            sub_url = sub_list[0]["subtitle_url"]
            if not sub_url.startswith("http"):
                sub_url = "https:" + sub_url
            response = requests.get(sub_url)
            if response.status_code == 200:
                raw_sub_titles = json.loads(response.content)["body"]
                raw_transcript = " ".join([c["content"] for c in raw_sub_titles])
 
                raw_transcript_with_meta_info = (
                    f"Video Title: {video_info['title']}, "
                    f"description: {video_info['desc']}\n\n"
                    f"Transcript: {raw_transcript}"
                )
                return raw_transcript_with_meta_info, video_info
            else:
                warnings.warn(
                    f"Failed to fetch subtitles for {url}. "
                    f"HTTP Status Code: {response.status_code}"
                )
                return "", video_info
        else:
            warnings.warn(
                f"No subtitles found for video: {url}. Returning empty transcript."
            )
            return "", video_info

其中SESSDATA，BUVID3，BILI_JCT 三个参数需要通过访问登录B站进行获取。固定值也是必须值，不需要刷新，永久有效，但是如果该账户访问次数过多和频繁存在被封禁情况，现在不知道b站那边封禁策略。

获取方法：打开b站网页，F12开发者工具，应用程序->cookies>www.bilibili.com 下的元素获取。

from langchain_community.document_loaders import BiliBiliLoader
SESSDATA = "***************************************"
BUVID3 = "**************************************"
BILI_JCT = "******************************************"
 
loader = BiliBiliLoader(
    [
        "https://www.bilibili.com/video/BV1PZ421S7VF/?spm_id_from=333.1007.tianma.1-2-2.click"
],
sessdata = SESSDATA,
bili_jct = BILI_JCT,
buvid3 = BUVID3,
)
docs = loader.load()
print(docs)

源码解析：

_get_bilibili_subs_and_info：

他是一个检索给定 BiliBili URL 的视频信息和文字记录。

获取到视频信息后，可以找到字幕URL的获取路径，访问该路径可以获取到字幕信息：

sub_list = sub["subtitles"]
if sub_list:
    sub_url = sub_list[0]["subtitle_url"]
    if not sub_url.startswith("http"):
        sub_url = "https:" + sub_url
    response = requests.get(sub_url)

例子：https://aisubtitle.hdslb.com/bfs/ai_subtitle/prod/125040837614317115816310f6f57f99190f192792b6f2d98ac0?auth_key=1708498531-6e1797becb564b90a29714989167da05-0-e9073436bc93efbbb4f87a3b0c3f7b3f

如果请求字幕接口成功，那么对于所有的返回的语音字幕文字进行处理：

response = requests.get(sub_url)
if response.status_code == 200:
    raw_sub_titles = json.loads(response.content)["body"]
    raw_transcript = " ".join([c["content"] for c in raw_sub_titles])
 
    raw_transcript_with_meta_info = (
        f"Video Title: {video_info['title']}, "
        f"description: {video_info['desc']}\n\n"
        f"Transcript: {raw_transcript}"
    )

问题：

1. 部分b站视频不支持语音文字字幕获取，获取时给错误提示，现在测试情况95%的是视频都是可以获取到了。

2. 目前视频语言字幕抓取语言，测试只抓取中文，抓取的数据目测是b站提供的字幕数据，其他国家的语言不提供一律转为中文。

3. AI 字幕需要使用登录账号的cookie进行请求，请求频繁或者过多会出现封禁，体现为接口返回正常返回内容，但是subtitle列表为空（即使实际上有ai字幕），无法获取subtitle_url。建议准备多个账号备用。

如果你有什么疑问就加入我们的公众号吧，我们能回答你的问题：