[NULL @ 0xe9eb3600] Unable to find a suitable output format for 'ffmpeg'

[CxBingo]

Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
creation_time : 1970-01-01 00:00:00
encoder : Lavf52.64.2
Duration: 00:00:10.00, start: 0.000000, bitrate: 1114 kb/s
Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 978 kb/s, 24 fps, 25 tbr, 25 tbn, 50 tbc (default)
Metadata:
creation_time : 1970-01-01 00:00:00
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 132 kb/s (default)
Metadata:
creation_time : 1970-01-01 00:00:00
handler_name : SoundHandler
[NULL @ 0xe9eb3600] Unable to find a suitable output format for 'ffmpeg'
ffmpeg: Invalid argument

How can dell that,I want to run " ffmpeg -i /sdcard/data/eloanvideo.mp4 -f image2 -vf fps=fps=1 /sdcard/data/data/%d.png"
and this is in Android Studio what " String[] commands = new String[9];
commands[0] = "ffmpeg";
commands[1] = "-i";
commands[2] = videoPath;
commands[3] = "-f";
commands[4] = "image2";
commands[5] = "-vf";
commands[6] = "fps=fps=1";
commands[7] = picture;
commands[8] = "out%d.png";

// String cmdString = " ffmpeg -i /sdcard/data/eloanvideo.mp4 -f image2 -vf fps=fps=1 /sdcard/data/data/%d.png";
try {
fFmpeg.execute(commands, new FFmpegExecuteResponseHandler() {
@OverRide
public void onSuccess(String message) {
Log.i("Bingo", "message:" + message);....."