DASHMPD文件内容解析

拿个MPD内容举个例子&＃xff1a;

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<AdaptationSet id&＃61;"1" group&＃61;"1" contentType&＃61;"audio" segmentAlignment&＃61;"true" audioSamplingRate&＃61;"48000" mimeType&＃61;"audio/mp4" codecs&＃61;"mp4a.40.2" startWithSAP&＃61;"1">














<SegmentTemplate timescale&＃61;"48000" initialization&＃61;"KabelEins_SD-$RepresentationID$.dash" media&＃61;"KabelEins_SD-$RepresentationID$-$Time$.dash">








<AdaptationSet id&＃61;"2" group&＃61;"2" contentType&＃61;"video" par&＃61;"16:9" minBandwidth&＃61;"576400" maxBandwidth&＃61;"2276800" maxWidth&＃61;"960" maxHeight&＃61;"540" minFrameRate&＃61;"25" maxFrameRate&＃61;"50" segmentAlignment&＃61;"true" sar&＃61;"1:1" mimeType&＃61;"video/mp4" startWithSAP&＃61;"1">

蓝色部分是EIT信息&＃xff0c;base64解密之后息的是&＃xff1a;EVENTID&＃61;25F4,VERSION&＃61;15,FLAG&＃61;0,STARTTIME&＃61;E6BC115957,DURATION&＃61;5235,STATUS&＃61;4,DESC_4D&＃61;6465750D48617761696920466976652D3042054265726569742066FC722065696E20537069656C3F8A4372696D652D53657269652C2055534120323031368A416C7465727366726569676162653A206162203132,DESC_BB&＃61;17,DESC_BC&＃61;57 

红色部分是加密信息&＃xff0c;里面有playready 和 widevine 加密default_KID&＃61;"C8EFFF27-6E1A-D9E6-693F-3E0B64C8EFEC"  kid信息。

紫色部分是音频分片信息 绿色是视频信息

来看音频信息&＃xff1a;

<SegmentTemplate timescale&＃61;"48000" initialization&＃61;"KabelEins_SD-$RepresentationID$.dash" media&＃61;"KabelEins_SD-$RepresentationID$-$Time$.dash">

timescale 时间精度&＃xff0c;也就是1秒的分辨率

initialization 初始化分片格式 KabelEins_SD-$RepresentationID$.dash 根据后面的RepresentationID audio_129713_deu&＃61;129200可知道该音频的初始化分片为 KabelEins_SD-audio_129713_deu&＃61;129200.dash 

media 媒体文件名称KabelEins_SD-$RepresentationID$-$Time$.dash 根据后面的RepresentationID  audio_129713_deu&＃61;129200和 SegmentTimeline 值可以知道实际分片&＃xff1a;

t 开始时间 d duration 实际分片时间是 d/timscale &＃61; 8s &＃xff0c;r repeat &＃xff0c;那么当前mpd文件 有三个分片 time 为&＃xff1a;

76646543257932/76646543257932&＃43;384000&＃61;76646543641932/76646543257932&＃43;384000&＃43;384000&＃61;76646544025932

KabelEins_SD-audio_129713_deu&＃61;129200-76646543257932.dash

KabelEins_SD-audio_129713_deu&＃61;129200-76646543641932.dash

KabelEins_SD-audio_129713_deu&＃61;129200-76646544025932.dash

同理可以推出视频信息&＃xff0c;那么针对该MPD内容我们可以得出如下的信息&＃xff1a;

1.dash流里有eit信息

2.dash流为加密流含有两种加密 playready 和 widevine

3.音频流只有一个格式分片 初始化分片&＃xff08;主要用于解码器预载&＃xff09;KabelEins_SD-audio_129713_deu&＃61;129200.dash  音频分片有三个 KabelEins_SD-audio_129713_deu&＃61;129200-76646543257932.dash/KabelEins_SD-audio_129713_deu&＃61;129200-76646543641932.dash/KabelEins_SD-audio_129713_deu&＃61;129200-76646544025932.dash 每个分片时长8s

4.视频流有多个带宽&＃xff0c;分片时长为8s &＃xff1a;

初始化分片 KabelEins_SD-video&＃61;576400.dash 分片信息 KabelEins_SD-video&＃61;576400-958081790714.dash/KabelEins_SD-video&＃61;576400-958081795514.dash/KabelEins_SD-video&＃61;576400-958081800314.dash/KabelEins_SD-video&＃61;576400-958081805114.dash/KabelEins_SD-video&＃61;576400-958081809914.dash

初始化分片 KabelEins_SD-video&＃61;1138400.dash 分片信息 KabelEins_SD-video&＃61;1138400-958081790714.dash/KabelEins_SD-video&＃61;1138400-958081795514.dash/KabelEins_SD-video&＃61;1138400-958081800314.dash/KabelEins_SD-video&＃61;1138400-958081805114.dash /KabelEins_SD-video&＃61;576400-958081809914.dash

初始化分片 KabelEins_SD-video&＃61;2276800.dash 分片信息 KabelEins_SD-video&＃61;2276800-958081790714.dash/KabelEins_SD-video&＃61;2276800-958081795514.dash/KabelEins_SD-video&＃61;2276800-958081800314.dash/KabelEins_SD-video&＃61;2276800-958081805114.dash/KabelEins_SD-video&＃61;576400-958081809914.dash