首先从抖音客户端找一个视频，点击分享-复制链接，粘贴一下发到电脑上，准备进行下一步，这里已经准备好了一个从客户端得到的分享文本。
把其中的链接粘贴到浏览器中访问一下，得到了这样的界面：
同时，地址栏中的链接变成了:
https://www.iesdouyin.com/share/video/6855476646057643272/?region=CN&mid=6855476868364192519&u_code=1l1346c029b7&titleType=title&utm_source=copy_link&utm_campaign=client_share&utm_medium=android&app=aweme
可见其发生了重定向。
F12审查一下播放区域：
发现这个时候播放区域只有一张背景图片和一个播放按钮，点击一下播放试试：
多了一个video标签，其中的src属性的值就是视频的url，所以大胆猜测一下，这个播放地址可能是通过ajax请求得到的。
切换到Network面板，点击xhr，再刷新一下页面，果然有一个ajax请求，这个ajax请求带有一个item_ids的参数，其值应该为视频的id，可以在页面重定向后的url中找到这个id：
响应结果是一个json字符串，复制到编辑器中格式化后如下：
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["https://p6-dy-ipv6.byteimg.com/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570?from=2563711402","https://p1-dy-ipv6.byteimg.com/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570?from=2563711402","https://p26-dy.byteimg.com/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570?from=2563711402"]},"status": {"status": 2,"is_collected": 0},"next_info": {"mix_name": "家乡变成二次元","desc": "原创不易，不喜勿喷～","cover_url": {"uri": "tos-cn-i-0813/57a48d47c61142748748802d08a75570","url_list": ["https://p1-dy.bytecdn.cn/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570","https://p3-dy.bytecdn.cn/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570","https://p9-dy.bytecdn.cn/obj/tos-cn-i-0813/57a48d47c61142748748802d08a75570"]}},"mix_name": "家乡变成二次元"},"music": {"status": 1,"id": 6855476868364193000,"mid": "6855476868364192519","cover_hd": {"url_list": 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信息还是蛮丰富的，作者信息、视频信息、音乐信息、封面信息等一应俱全，视频的地址是在item_list下video.play_addr.url_list中，复制下这个地址用浏览器访问一下果然得到了视频：
不过这个视频还是带水印的，如何获得没有水印的视频呢，来看看从json字符串中得到的视频地址：
https://aweme.snssdk.com/aweme/v1/playwm/?video_id=v0200fda0000bshokcp94bbr1103bot0&ratio=720p&line=0
觉不觉得这个playwm中的wm是water mask的简写呢，把wm删掉再访问一下试试。即：
https://aweme.snssdk.com/aweme/v1/play/?video_id=v0200fda0000bshokcp94bbr1103bot0&ratio=720p&line=0
结果一片空白，是不是这样行不通呢，不应该啊，不然直接写play多好，何必又搞个playwm呢，一定是访问姿势有问题，点击左上角的设备切换按钮切换到移动端访问一下，哇，amazing，竟然真的访问到了！
同时可以看到原本左上角的抖音水印消失了。成功！
思路总结：
访问客户端分享文本中的链接，从重定向后的url中提取视频id，https://www.iesdouyin.com/share/video/后的数字就是视频id。
访问https://www.iesdouyin.com/web/api/v2/aweme/iteminfo/?item_ids=视频id获取有关该视频的json字符串。
从得到的json字符串中提取视频播放地址，在item_list下video.play_addr.url_list中。
将视频地址中的playwm替换为play。
使用移动端的user-agent访问替换后的视频地址即可得到无抖音水印的视频。
本人已使用node.js简单地写了一个抖音无水印视频的解析库，并发布在了npm和github上，详情请访问：
npm：
https://www.npmjs.com/package/douyin_video
github：
https://github.com/xyz-studio/Douyin_Video
文章转载自微信公众号CodeCube
