Android: how to get a video thumbnail of a file that's private to your application?

Question

Question:

How do you get a video thumbnail for an application-private file? Specifically, is there a way to extract video frames from an .mpeg file directly?

Background:

1. My application includes a camera that can record video.
2. For product reasons, the video file is initially created and written in private mode in the application's private data directory, making it private to the application. This is done using: Context#openFileOutput(fileName, Context.MODE_PRIVATE) - a typical file path looks like this: /data/data/[package.name]/files/[fileName].mp4 -- FYI I already tried using Context.MODE_WORLD_READABLE instead of Context.MODE_PRIVATE but it didn't help.
3. Even though the video may eventually end up in external storage (by moving the file to Environment#getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES)), the thumbnail must be displayed while the video is in application-private storage.

4. It seems like ThumbnailUtils.createVideoThumbnail(String, int) works fine for the file after it is moved to the public directory (regardless of adding it to the MediaStore), but silently fails (returns null) when the file is in internal storage.

   • Note: as long as the video file is in application-private storage, it is not added to the MediaStore (the image/video content provider on the device Gallery feeds on). Only once the video is moved to external storage do I add it the MediaStore. This is a product-related decision which I cannot circumnavigate; unless there's a way to add the video the media store without it being visible to other apps... I wonder if videos in application-private storage can be added to the media store and would remain application-private but gain all the free "services" provided by the media store such as thumbnail generation.

Answer 1

Of course, you can't use MediaStore stuff for private media. I would use a image process library if it is possible at all. I know OpenCV can do that easily by extracting/resizing a frame. - please look at middle section of page 2.