TS片头片中广告新增混淆功能，极大降低广告插件识别和拦截概率

目前视频插播片头片中广告是普遍方式，但去插播广告的插件和播放器越来越多，比如会根据广告和视频切片的路径差异等特征进行识别，导致该功能效果大幅下降。

所以目前有必要弄一个插播混淆功能，即用户在播放层面获取m3u8文件时，动态重写m3u8内容，使视频切片与广告切片特征完全一样，极大降低广告插件识别和拦截概率。

如这是插播片头和片中广告，但未开启混淆功能的m3u8内容：
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:9
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXTINF:8.913044,
/stream/202604/30/69f31a1c74beb93d212dd423/4b851e/index0.ts
#EXTINF:7.608700,
/stream/202604/30/69f31a1c74beb93d212dd423/4b851e/index1.ts
#EXTINF:0.173911,
/stream/202604/30/69f31a1c74beb93d212dd423/4b851e/index2.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index0.ts
#EXTINF:7.608700,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index1.ts
#EXTINF:8.608689,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index2.ts
#EXTINF:7.304356,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index3.ts
#EXTINF:7.739122,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index4.ts
#EXTINF:9.000000,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index5.ts
#EXTINF:6.869567,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index6.ts
#EXTINF:8.956522,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index7.ts
#EXTINF:7.000000,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index8.ts
#EXTINF:8.391300,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index9.ts
#EXTINF:7.826089,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index10.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/stream/202604/30/69f31a2a74beb93d212dd4f4/adc12b/index0.ts
#EXTINF:7.608700,
/stream/202604/30/69f31a2a74beb93d212dd4f4/adc12b/index1.ts
#EXTINF:0.173911,
/stream/202604/30/69f31a2a74beb93d212dd4f4/adc12b/index2.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.695656,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index11.ts
#EXTINF:7.608700,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index12.ts
#EXTINF:8.347822,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index13.ts
#EXTINF:7.608700,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index14.ts
#EXTINF:8.434778,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index15.ts
#EXTINF:7.608700,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index16.ts
#EXTINF:7.652167,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index17.ts
#EXTINF:9.000000,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index18.ts
#EXTINF:7.826089,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index19.ts
#EXTINF:7.695656,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index20.ts
#EXTINF:7.652167,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index21.ts
#EXTINF:8.173922,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index22.ts
#EXTINF:8.391300,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index23.ts
#EXTINF:3.739089,
/videos/202604/30/69f31aca74beb93d212ddaf8/f7787d/index24.ts
#EXT-X-ENDLIST

这是开启混淆功能后的m3u8内容：
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:9
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXTINF:8.913044,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/lY01DiOoX995.ts
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/c7zUbRnWebsm.ts
#EXTINF:0.173911,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/tBXbWnJgSQ7C.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/3XQ58FgFUZlN.ts
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/fJxa6DYqCDfO.ts
#EXTINF:8.608689,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/dmMsfSQ7hJH5.ts
#EXTINF:7.304356,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/kr6G4ARauG0s.ts
#EXTINF:7.739122,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/b2ADj7KBAgKG.ts
#EXT-X-DISCONTINUITY
#EXTINF:9.000000,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/2dp7NLTs0ucG.ts
#EXTINF:6.869567,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/zOaeVRoHzwjX.ts
#EXTINF:8.956522,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/d1jxAMZasrqa.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.000000,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/i2gtF9F9N4hD.ts
#EXTINF:8.391300,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/IUWwtpUEUTvT.ts
#EXTINF:7.826089,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/OE0moJWgAw71.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/FXrmrUZwLn99.ts
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/HGNr7OYPrSBu.ts
#EXTINF:0.173911,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/RO6ddr4gO9qI.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.695656,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/AMHqrISVgjgW.ts
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/ItZmVtYEkOqv.ts
#EXTINF:8.347822,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/1qSzWBjJdgzI.ts
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/76BWcLK8RraP.ts
#EXTINF:8.434778,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/kPtj4qZ8v9BO.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.608700,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/CmbWQEb1p7vt.ts
#EXTINF:7.652167,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/MASnMfxNaDZR.ts
#EXTINF:9.000000,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/MQ05iZkCdxlZ.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.826089,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/wHNZcVAKmhiv.ts
#EXTINF:7.695656,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/oK3e2QsEi8Z9.ts
#EXTINF:7.652167,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/IwWaOpOihdfg.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.173922,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/zFkdNHjo7QaA.ts
#EXTINF:8.391300,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/IrlmtJpFrXVG.ts
#EXTINF:3.739089,
/chunk/5cfe5ce7b1bcbe9832b17181e04d4986/kC7rNeeOJyDD.ts
#EXT-X-ENDLIST

也就是混淆后，视频切片与广告切片特征完全一样了，无法通过路径识别，并且再从正片里面提取相同数量的切片伪装成广告的样式，且同一个广告在每一个视频里面的路径也都会不一样，极大降低了广告插件识别和拦截概率。

如果视频开启了TS加密，那么插播的所有片头片中广告切片都会和视频共用一个ts.key，此时m3u8内容如下：

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:9
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-KEY:METHOD=AES-128,URI="/videos/202604/30/69f31a8474beb93d212dd87b/ts.key",IV=0x3de234ce4da88bae7e29c05c70a99193
#EXTINF:8.913044,
/chunk/08150493f9724c29ea937897bd85168a/lY01DiOoX995.ts
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/c7zUbRnWebsm.ts
#EXTINF:0.173911,
/chunk/08150493f9724c29ea937897bd85168a/tBXbWnJgSQ7C.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/chunk/08150493f9724c29ea937897bd85168a/crhjjH1Vrkh0.ts
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/oKZRlMOl2v63.ts
#EXTINF:8.608689,
/chunk/08150493f9724c29ea937897bd85168a/rB4Wpw6haHDG.ts
#EXTINF:7.304356,
/chunk/08150493f9724c29ea937897bd85168a/2kdaK1adTjko.ts
#EXTINF:7.739122,
/chunk/08150493f9724c29ea937897bd85168a/ho25yOGHs7VT.ts
#EXT-X-DISCONTINUITY
#EXTINF:9.000000,
/chunk/08150493f9724c29ea937897bd85168a/5lKX3oCcr1vL.ts
#EXTINF:6.869567,
/chunk/08150493f9724c29ea937897bd85168a/vC9bC1yLjbVU.ts
#EXTINF:8.956522,
/chunk/08150493f9724c29ea937897bd85168a/QO0ZUiRjkv09.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.000000,
/chunk/08150493f9724c29ea937897bd85168a/vc8kloeYx2iF.ts
#EXTINF:8.391300,
/chunk/08150493f9724c29ea937897bd85168a/Zn55DCpDm8NZ.ts
#EXTINF:7.826089,
/chunk/08150493f9724c29ea937897bd85168a/EwpRGq9kuD01.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.913044,
/chunk/08150493f9724c29ea937897bd85168a/FXrmrUZwLn99.ts
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/HGNr7OYPrSBu.ts
#EXTINF:0.173911,
/chunk/08150493f9724c29ea937897bd85168a/RO6ddr4gO9qI.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.695656,
/chunk/08150493f9724c29ea937897bd85168a/2tMu7H3czm1H.ts
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/7ALwsyGvtmxf.ts
#EXTINF:8.347822,
/chunk/08150493f9724c29ea937897bd85168a/0BP3qP6YyI7S.ts
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/DvDKOmE5eAyc.ts
#EXTINF:8.434778,
/chunk/08150493f9724c29ea937897bd85168a/bTSYjZwu0t5F.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.608700,
/chunk/08150493f9724c29ea937897bd85168a/QzgAikQOo8Ws.ts
#EXTINF:7.652167,
/chunk/08150493f9724c29ea937897bd85168a/bPRlSszuycK3.ts
#EXTINF:9.000000,
/chunk/08150493f9724c29ea937897bd85168a/V4bTn24zcNvo.ts
#EXT-X-DISCONTINUITY
#EXTINF:7.826089,
/chunk/08150493f9724c29ea937897bd85168a/8MI5RHhgo7BU.ts
#EXTINF:7.695656,
/chunk/08150493f9724c29ea937897bd85168a/kj3WWpxdpQKN.ts
#EXTINF:7.652167,
/chunk/08150493f9724c29ea937897bd85168a/GPrfMCD3zelT.ts
#EXT-X-DISCONTINUITY
#EXTINF:8.173922,
/chunk/08150493f9724c29ea937897bd85168a/4iuqG0V2GCBd.ts
#EXTINF:8.391300,
/chunk/08150493f9724c29ea937897bd85168a/zKiEkaT0nEWw.ts
#EXTINF:3.739089,
/chunk/08150493f9724c29ea937897bd85168a/ACLJ7p1mue0E.ts
#EXT-X-ENDLIST

也就是就算开了TS加密的视频切片，也丝毫不影响混淆结果。

最后，如果开启了生成PNG切片，TS伪装JPEG等功能，广告切片也会自适应动态的进行处理，即也会跟着变成png或jpeg切片，即完美兼容各种样式的切片。