前言
西电的录直播功能一直是烂的不行，但是在西电用iframe升级了一下之后总归是能正常打开页面了，当然播放是基本不可能的事情，所以唯一的办法就是先下载下来再观看了。
ps：这篇文章写于2022/3/8，以后如果西电系统升级了可能就不行了
1.获取m3u8地址
现在很多网站的视频的播放都是用的m3u8格式，m3u8可以理解为索引表，当你观看视频的时候根据索引表去把视频一小段一小段的下载下来以保证观看流畅（对于西电来说能打开就已经是万幸了）所以你只需要获取m3u8地址然后下载就可以了。
首先进入你要观看的录播网页，按F12进入开发者模式，然后找到iframe标签，如下图：
然后双击ifrme复制其src，你会得到类似这样的一大串路径
http:///newes.learning.xidian.edu.cn/threepart/index-alihls.html?info=%7B%22type%22%3A%222%22%2C%22videoPath%22%3A%7B%22pptVideo%22%3A%22http%3A%2F%2Fvodvtdu1.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F688a759fdffe4176bc79af2def2c97c4%2F1%2F1639618539%2F1639621837%2F0%2Fplayback.m3u8%22%2C%22mobile%22%3A%22http%3A%2F%2Fvodvtdu1.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F95a6ca1ad5174a0e9aa4609b05bbf416%2F1%2F1639619243%2F1639622540%2F0%2Fplayback.m3u8%22%2C%22teacherTrack%22%3A%22http%3A%2F%2Fvodvtdu1.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F75a0fe6308914effa91c73f4a3622fac%2F1%2F1639619985%2F1639623281%2F0%2Fplayback.m3u8%22%2C%22studentFull%22%3A%22http%3A%2F%2Fvodvtdu3.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F5c1f60465514410eab5920040c16c834%2F1%2F1639620684%2F1639623980%2F0%2Fplayback.m3u8%22%7D%7D
之后删除info之前部分，以http为界，把这一大串分解一下变成这样，到这一步基本就能很清晰的看出这是四个对象，分别对应四种视角
{"pptVideo"%3A"http%3A%2F%2Fvodvtdu4.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2Faee6f6b53c6842399176d8610868b856%2F1%2F1635201181%2F1635204180%2F0%2Fplayback.m3u8"%2C "mobile"%3A"http%3A%2F%2Fvodvtdu8.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F03b8d19133354933a47d0bdcd312544a%2F1%2F1635201653%2F1635204652%2F0%2Fplayback.m3u8"%2C "teacherTrack"%3A"http%3A%2F%2Fvodvtdu8.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F0cec472ca84c4f24b05f282f7b659e3f%2F1%2F1635203000%2F1635205996%2F0%2Fplayback.m3u8"%2C "studentFull"%3A"http%3A%2F%2Fvodvtdu8.xidian.edu.cn%3A8092%2Ffile%2Fcloud%3A%2F%2F10.168.76.10%3A6201%2FHIKCLOUD%2Faccessid%2FNUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2%2Faccesskey%2Fa3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN%2Fbucket%2Fbucket%2Fkey%2F467c7219d63f4bbfafce586cce0193a9%2F1%2F1635204540%2F1635207535%2F0%2Fplayback.m3u8"}
对其进行转码，这一步你可以自己写个算法，也可以调用各个语言的库，当然也可以直接使用在线转码网站把这些看起来陌生的串变成熟悉的url
{"pptVideo":"http:///vodvtdu4.xidian.edu.cn:8092/file/cloud://10.168.76.10:6201/HIKCLOUD/accessid/NUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2/accesskey/a3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN/bucket/bucket/key/aee6f6b53c6842399176d8610868b856/1/1635201181/1635204180/0/playback.m3u8", "mobile":"http:///vodvtdu8.xidian.edu.cn:8092/file/cloud://10.168.76.10:6201/HIKCLOUD/accessid/NUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2/accesskey/a3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN/bucket/bucket/key/03b8d19133354933a47d0bdcd312544a/1/1635201653/1635204652/0/playback.m3u8", "teacherTrack":"http:///vodvtdu8.xidian.edu.cn:8092/file/cloud://10.168.76.10:6201/HIKCLOUD/accessid/NUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2/accesskey/a3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN/bucket/bucket/key/0cec472ca84c4f24b05f282f7b659e3f/1/1635203000/1635205996/0/playback.m3u8", "studentFull":"http:///vodvtdu8.xidian.edu.cn:8092/file/cloud://10.168.76.10:6201/HIKCLOUD/accessid/NUVQYWFpMEp6c0ppVVJkdFVMbDc5N3VVZjU1MWw4Szc2ODEyOGYyejdHNzkxN2FJMlhYNmQyNzQ0ZDNpTDM2/accesskey/a3gxcEs3SVNiN1lCeTFoOW80OThPb3o4N3I3R3hBQnpFajY3NUk3NVJ6VDdUNDdubTQ4UzQxNDUwN3RRZDJN/bucket/bucket/key/467c7219d63f4bbfafce586cce0193a9/1/1635204540/1635207535/0/playback.m3u8"}
上面前四个链接（从http到.m3u8部分）应该能看出分别对应四种视角。一般情况下使用第一和第二个就可以了。至此m3u8链接的获取就完成了。
2.播放或者下载m3u8
播放
播放可以使用potplayer，但是播放的体验并不好，即使可以加载出来也无法快进、加速等，而且网络不好还会卡顿，并不推荐
下载
下载的话方法也是很多，可以自行搜索，我这里用的是别人开发的小工具：下载地址 这个工具能方便的批量下载，可以晚上睡觉的时候全部下载好还是非常方便的。
因为下载分片可能会出错，所以用这个工具下载时可以在下载栏勾选上‘分片忽略失败’
下载好之后就和普通的mp4文件没什么区别可以随意使用了
