Is it possible to use a DocumentFile or outputstream for FFmpegFrameRecorder on Android?

[pgfsim]

I am able to create a video from images by initialising the recorder with a video location to save to, and a video height and width. recorder = new FFmpegFrameRecorder(videosavelocation, reswidth, resheight);

This works perfectly for internal storage, but I'm now interested in saving to the SD card. I'm able to get read/write access by using the Storage Access Framework. However, the issue is you can't use java.io.File to access the SD card, you must use DocumentFile.

If I use getUri().toString() or getUri().getPath() FFmpeg expectedly can't open it:
W/System.err: org.bytedeco.javacv.FrameRecorder$Exception: avio_open error() error -1330794744: Could not open 'content://com.android.externalstorage.documents/tree/3163-6261%3A/%2Fmyvideo.mp4

I can create an empty mp4 file on the SD card like so, with a DocumentFile:

 DocumentFile sdDir = vidsavelocationSD.createFile("video/mp4",videotimeStamp+".mp4");

                try {
                    OutputStream out = getApplicationContext().getContentResolver().openOutputStream(sdDir.getUri());
                    out.write("".getBytes());
                    out.close();

                } catch (IOException e) {
                    e.printStackTrace();
                }

Is there any way to use FFmpegFrameRecorder and be able to save to the SD card?

I'm using the latest javacpp/javacv built from source, and targeting API 23 in my project for android-arm.

[saudet]

Duplicate of #95. As you can see, it's a frequently requested feature, so it would be very helpful if you could make a contribution. If you run into any problems when implementing it though, let me know! Thanks for your interest