从iOS中捕获的视频中获取慢动作元数据 [英] Getting Slow Motion meta data from captured video in iOS

问题描述

我们有一个视频应用程序，用于从用户的相机胶卷导入视频。我们的问题是导入使用本机Camera应用程序拍摄的慢动作视频。我们可以认识到帧速率高于正常（例如120或240 fps）。

We have a video app that is importing video from the user's camera roll. Our problem is importing slo-mo video taken with the native Camera app. We can recognise that there is a higher than normal frame rate (e.g. 120 or 240 fps).

我们找不到的是元信息，它指定视频何时进入慢动作以及何时再次加速。有谁知道这些信息保存在哪里，和/或如何获取信息？它是在文件本身中，还是存储在某个单独的元文件中？

What we can't find is the meta information that specifies when the video drops into slow motion and when it speeds up again. Does anyone know where this information is kept, and/or how to get at it? Is it in the file itself, or stored in a separate meta file somewhere?

非常感谢任何帮助，谢谢！

Any help would be hugely appreciated, thanks!

推荐答案

慢动作片段在技术上不是元数据。它们的类型为 UITrackSegment ，您可以阅读这里

The slow motion segments are technically not metadata. They are of type UITrackSegment which you can read about here

轨道上缩放方法的结果会创建一个timeMapping对象，该对象以其source.duration / target.duration的速率播放轨道。您可以在此博文中阅读更多相关信息。

The result of a scaling method on a track creates a timeMapping object that plays the track at the rate of it's source.duration / target.duration. You can read more about that in this blog post.

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