You can use jcodec SequenceEncoder
to convert sequence of images to MP4 file.
Sample code :
import org.jcodec.api.awt.SequenceEncoder;
...
SequenceEncoder enc = new SequenceEncoder(new File("filename"));
// GOP size will be supported in 0.2
// enc.getEncoder().setKeyInterval(25);
for(...) {
BufferedImage image = ... // Obtain an image to encode
enc.encodeImage(image);
}
enc.finish();
It’s a java library so it’s easy to import it into Android project, you don’t have to use NDK unlike ffmpeg.
Refer http://jcodec.org/ for sample code & downloads.