Android : Reduce the size of video for upload on server

after finding lost of stuff and blog i am finally found the FFmpeg4Android lib to convert the video size from here now my problem is the whenever i am try to convert the video instead of redusing the size it is increase the size the command which i am use is share below

 commandStr = "ffmpeg -y -i /sdcard/videokit/in.mp4 -strict experimental -s 320x240 -r 14 -aspect 3:4 -vcodec mpeg4 -b 2097152 -ab 48000 -ac 2 -ar 22050 /sdcard/videokit/in_.mp4";
setCommand(commandStr);

                    setOutputFilePath("/sdcard/videokit/out.mp4");
                    setProgressDialogTitle("Exporting As MP4 Video");
                    setProgressDialogMessage("Depends on your video size, it can take a few minutes");
runTranscoing();

i am not getting any error the problem is only it increase the size of video. may be i am giving wrong command so any one can suggest me if i am going wrong.