Javascript 是否可以反向播放 HTML5 视频？
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Is it possible to play HTML5 video in reverse?
提问by Ish
Is HTML5 <video>tag be play video in reverse, or I have to download 2 videos (forward and backword play). Any solution that avoid user from downloading 2 videos?
HTML5<video>标签是反向播放视频，还是我必须下载 2 个视频（正向和反向播放）。任何避免用户下载 2 个视频的解决方案？
采纳答案by Frédéric Hamidi
Without even going into HTML5 or Javascript, many video formats are streamingformats that are designed to be played forward. Playing it backwards would require decoding the whole stream, storing each raw frame on the disk to avoid clobbering memory, then rendering the frames backwards.
甚至无需使用 HTML5 或 Javascript，许多视频格式都是旨在向前播放的流格式。向后播放需要解码整个流，将每个原始帧存储在磁盘上以避免破坏内存，然后向后渲染帧。
At least one person actually tried thatusing mplayer, though, so it canbe done, at least in principle.
不过，至少有一个人实际尝试过使用mplayer，因此可以做到，至少在原则上是这样。
回答by Eli Grey
aMediaElement.playbackRate = -1;
UAs may not support this, though it is valid to set playbackRateto a negative value.
UA 可能不支持这一点，尽管设置playbackRate为负值是有效的。
回答by BaptisteB
I managed to do it in an update method. Every frame I decrease video.currentTime to the time elapsed and so far it is the best result I managed to get.
我设法在更新方法中做到了。每一帧我都将 video.currentTime 减少到经过的时间，到目前为止，这是我设法获得的最佳结果。
