检测视频是否以人像/风景拍摄 [英] Detecting if video was taken in portrait/landscape

问题描述

我想确认我所做的确实是正确的方法，因为某些元素的行为异常.

I would like to confirm that what I am doing is indeed the correct way as some elements behave unexpected.

首先，据我了解，我有横向和纵向布局，这样做会自动检测手机是否处于纵向/横向模式:

First, I have a landscape and portrait layout, as I understand, doing this will automatically detect if the phone is in portrait/landscape mode:

- layout
   - activity_video_player.xml
 - layout-land
   - activity_video_player.xml

然后，当用户从图库中选择一个视频时，通过执行以下操作(在OnCreate内部)，我会检查该视频是横向拍摄还是纵向拍摄:

Then when the user selects a video from the gallery, I check if the video was taking in landscape or portrait, by doing this (inside OnCreate):

int w;
int h;

MediaMetadataRetriever mediaMetadataRetriever = new MediaMetadataRetriever();
mediaMetadataRetriever.setDataSource(this, videoURI);
String height = mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT);
String width = mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH);
w = Integer.parseInt(width);
h = Integer.parseInt(height);

if (w > h) {  
    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
} else {
    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

我已经对此进行了测试，并且可以正常工作，但是我注意到我的某些xml元素(播放按钮)放置不正确.

I have tested this and it works fine, but I noticed some of my xml elements (play button) is placed incorrectly.

所以我的应用程序流程是:

So my app flow is:

MainActivity --> SelectvidButton --> Gallery Intent --> VideoPlayActivity

---

我的问题

这是正确的方法吗?如果是，是否有某些原因导致某些xml元素放置不正确?

Is this the correct way of doing this and if it is, is there any reason why some of the xml elements get placed incorrectly?

我注意到只有在首次启动活动时才会发生这种情况，如果我按后退"按钮并再次选择同一视频，则布局完全像我想要的那样.

I noticed that this only happens when the activity is launched for the first time, if I press the back button and select the same video again, the layout is perfectly like I want it to be.

我还注意到，只有在上一个活动(MainActivity)的方向与所选视频的方向相同时，这种情况才会发生.

I have also noticed that this only happens if the previous activity (MainActivity) was in the same orientation than what the selected video is.

推荐答案

这就是我最终要做的事情.

Here is what I ended up doing.

我不是使用MediaMetadataRetriever来获取宽度和高度，而是首先从视频文件中检索Bitmap，然后根据Bitmap的宽度和高度来设置方向，如下所示:

Instead of using MediaMetadataRetriever to get the width and height, I first retrieve a Bitmap from the video file and then setting the orientation according to the width and hight of the Bitmap, as shown below:

private void rotateScreen() {
    try {
        //Create a new instance of MediaMetadataRetriever
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();
        //Declare the Bitmap
        Bitmap bmp;
        //Set the video Uri as data source for MediaMetadataRetriever
        retriever.setDataSource(this, mVideoUri);
        //Get one "frame"/bitmap - * NOTE - no time was set, so the first available frame will be used
        bmp = retriever.getFrameAtTime();

        //Get the bitmap width and height
        videoWidth = bmp.getWidth();
        videoHeight = bmp.getHeight();

        //If the width is bigger then the height then it means that the video was taken in landscape mode and we should set the orientation to landscape
        if (videoWidth > videoHeight) {
            //Set orientation to landscape
            this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        }
        //If the width is smaller then the height then it means that the video was taken in portrait mode and we should set the orientation to portrait
        if (videoWidth < videoHeight) {
            //Set orientation to portrait
            this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        }

    } catch (RuntimeException ex) {
        //error occurred
        Log.e("MediaMetadataRetriever", "- Failed to rotate the video");

    }
}

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