使用FFmpeg的基于其与LT旋转视频;旋转＆GT;元数据？为什么Android的放错了元数据？ [英] Use FFmpeg to rotate the video based on its <rotate> metadata? Why does Android put the wrong metadata?
问题描述
我有一个网站，用户上传的视频。结果
对于我的网站，我也有一个Android应用程序。结果
该网站（从浏览器或Android）创建每个上传视频的缩略图。
I have a website where the user uploads a video.
For my website i have also an Android application.
The website creates a thumbnail of each uploaded video (from browser or Android).
问题是正常的视频这一切都不错，但为Android我的视频被旋转90°。
The problem is that for normal videos it's all OK, but for android my videos are rotated by 90°.
我认为，Android有一个漏洞，因为当我的FFmpeg看到该视频的元数据，对于一个正常录制的视频我得到了一个旋转= 90值以及90°旋转的视频，我没有在任何元数据（以及缩略图是正确的）。
I think that Android has a bug, because when I see with FFmpeg the video's metadata, for a normal recorded video I got a rotate=90 value, and for a 90° rotated video, I don't have anything in the metadata (and the thumbnail is correct).
为什么呢？
这是一个正常录制的视频图像（与手机的肖像模式）。
This is an image of a normal recorded video (with the phone in portrait mode).
反正我在视频中的元数据，我可以创建基于元数据的缩略图而不提取元数据旋转值，然后使用的ffmpeg 旋转此值的视频？
Anyway, I have the metadata in the video, can I create its thumbnail based on its metadata's rotate value without extracting the metadata and then use ffmpeg to rotate the video on this value?
感谢您提前。
推荐答案
在Android上，拿着手机在肖像被认为是90度。这一点，Android是用约定：
On android, holding your phone in portrait is considered to be 90 degrees. This the convention that android is using:
景观：0
画像：90
相反的景观：180
相反的肖像：270
landscape: 0 portrait: 90 reverse landscape: 180 reverse portrait: 270
我知道这是没有道理的手机，但它确实为平板电脑并没有真的在Android平板电脑和手机之间没有什么区别。
I know this doesn't make sense for phones but it does for tablets and there is realy no difference between tablets and phones on android.
因此，文件中的元数据是正确的。实际的问题是，您的浏览器会忽略它们。见我问
So the metadata in the file are correct. The actual problem is that your browser ignores them. See me question here
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