To play MP4 video in WebView, you need to first declare Content Provider in Manifest −
<provider android:name = "MyDataContentProvider" android:authorities="com.myapp" />
Implement open file with open() method −
URI myURL = URI.create("file:///mypath/new.mp4"); File f = new File(myURL); ParcelFileDescriptor p = ParcelFileDescriptor.open(f, ParcelFileDescriptor.MODE_READ_ONLY); return p;