为什么Iphone视频倒挂？ [英] Why are Iphone videos upside down?

问题描述

我使用 btsync 从Iphone5上复制的标准相机应用程序捕获的视频文件>：

I have a video file captured using the standard Camera app copied off my Iphone5 using btsync:

orig.mov: ISO Media, Apple QuickTime movie

在mplayer或vlc中播放颠倒。

That plays upside down in mplayer or vlc.

当我转码使用AWS的弹性转码器使用标准预设：

When I transcode it using AWS's elastictranscoder using a standard preset:

elastictranscoder.mpg: ISO Media, MPEG v4 system, version 1

转码视频文件播放正确的方式。

That transcoded video file plays back the right way up.

当转码自己时，使用ffmpeg我需要明确地旋转视频，否则的话结果{mp4，webm}文件是颠倒的。

When transcoding myself, using ffmpeg I need to explicitly rotate the video otherwise the resulting {mp4,webm} files are upside down.

所以我猜测AWS的弹性转码器会以某种方式自动旋转视频。但是，为什么视频颠倒开始？

So I am guessing AWS's elastictranscoder auto rotates the video somehow. However why is the video upside down to begin with?

推荐答案

这是一个苹果的事情，我同意这是非常混乱的大多数用户。苹果公司允许设备上的volme up / down按钮（iPhone / iPad）记录启动/停止和快门功能。因此，大多数用户希望这些按钮在顶部存在，因此旋转设备。

This is an Apple thing and I agree it is very confusing to most users. The Apple has allowed the volme up/down buttons on the device(iPhone/ iPad) to record start/stop and shutter functions. So, most users wants these buttons to be present at the top and hence rotate the device.

这使得设备开始重新录制视频，但是Apple运动传感器旋转视频，因此用户不会怀疑视频正在颠倒。

This makes the device starts recording the video upside down but Apple motion sensors rotate the video as well and hence the user does not suspect that the video is recording upside down.

通常，如果要避免现象，请按住右侧Home按钮的设备

As a rule, hold the device with Home button on the right side if you want to avoid the phenomenon.

PS：如果您想知道苹果应用程序是否始终将视频正确放置在正确的位置，那么答案就在于旋转标签嵌入在视频中，应用程序读取并更正其位置。

PS: In case you are wondering how Apple apps always position the video correctly even if it is recorded upside-down, the answer lies in the rotate tag which is embedded in the video and apps read it and correct the position.

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