How to reverse a video using ffmpeg in android?

Question

I wanna reverse a video which loaded from gallery and Camera. video converts into image frames and frames convert into reverse video using ffmpeg commands.

Answer 1

From https://stackoverflow.com/a/8137637/2930834

• http://ubuntuforums.org/showthread.php?t=1353893

The latter of which follows:

Dump all video frames

$ ffmpeg -i input.mkv -an -qscale 1 %06d.jpg

Dump audio

$ ffmpeg -i input.mkv -vn -ac 2 audio.wav

Reverse audio

$ sox -V audio.wav backwards.wav reverse

Cat video frames in reverse order to FFmpeg as input

$ cat $(ls -t *jpg) | ffmpeg -f image2pipe -vcodec mjpeg -r 25 -i - -i backwards.wav -vcodec libx264 -vpre slow -crf 20 -threads 0 -acodec flac output.mkv

Use mencoder to deinterlace PAL dv and double the frame rate from 25 to 50, then pipe to FFmpeg.

$ mencoder input.dv -of rawvideo -ofps 50 -ovc raw -vf yadif=3,format=i420 -nosound -really-quiet -o - | ffmpeg -vsync 0 -f rawvideo -s 720x576 -r 50 -pix_fmt yuv420p -i - -vcodec libx264 -vpre slow -crf 20 -threads 0 video.mkv

Also worth checking,

• https://video.stackexchange.com/a/17739

I haven't tried it. Hope this helps

Answer 2

1.Divide video into segments with duration of 10 seconds or less(below command has 6 seconds)

String[] complexCommand = {"-i", inputFileAbsolutePath, "-c:v", "libx264", "-crf", "22", "-map", "0", "-segment_time", "6", "-g", "9", "-sc_threshold", "0", "-force_key_frames", "expr:gte(t,n_forced*6)", "-f", "segment", outputFileAbsolutePath};

2.Reverse the segmented videos

With Audio

String command[] = {"-i", inputFileAbsolutePath, "-vf", "reverse", "-af", "areverse", outputFileAbsolutePath};

Without Audio

String command[] = {"-i",inputFileAbsolutePath, "-vf", "reverse", outputFileAbsolutePath};

3.Concatenate reversed segmented videos in reverse order

With Audio

String command[] = {"-i",inputFile1AbsolutePath,"-i",inputFile2AbsolutePath .....,"-i",inputFileNAbsolutePath,"-filter_complex","[0:v0] [0:a0] [1:v1] [1:a1]...[N:vN] concat=n=N:v=1:a=1 [v] [a],"-map","[v]","-map","[a]", outputFileAbsolutePath};

Without Audio

String command[] = {"-i",inputFile1AbsolutePath,"-i",inputFile2AbsolutePath .....,"-i",inputFileNAbsolutePath,"-filter_complex","[0:0] [1:0] [2:0]...[N:0] concat=n=N:v=1:a=0",outputFileAbsolutePath};

For detailed explanation check out this and sample code here

Answer 3

This sample code is only video reverse not included audio.

build.gradle

compile 'com.writingminds:FFmpegAndroid:0.3.2'

Before command execute, you need to load binary first

FFmpeg ffmpeg = FFmpeg.getInstance(this);

try {
        ffmpeg.loadBinary(new FFmpegLoadBinaryResponseHandler() {
        @Override
        public void onFailure() {

        }

        @Override
        public void onSuccess() {

        }

        @Override
        public void onStart() {

        }

        @Override
        public void onFinish() {

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

After load binary, you can execute your command.

String strInputVideoPath = dir.getAbsolutePath()  + "/" + "1543999518815.mp4";
String strRevOutputVideoPath = dir.getAbsolutePath() + "/" + "reverse.mp4";    
String[] cmdRevVid = {"-i",  strInputVideoPath,"-vf","reverse", strRevOutputVideoPath};
            try {
                ffmpeg.execute(cmdRevVid, new ExecuteBinaryResponseHandler(){
                    @Override
                    public void onStart() {

                    }

                    @Override
                    public void onProgress(String message) {

                    }

                    @Override
                    public void onFailure(String message) {

                    }

                    @Override
                    public void onSuccess(String message) {

                        try{



                        }catch (Exception ex){

                        }
                    }

                    @Override
                    public void onFinish() {

                    }
                });

            } catch (FFmpegCommandAlreadyRunningException e) {
                // Handle if FFmpeg is not supported by device
            }

In my case, I have to do reverse video and concat video itself. Reference Post

String[] cmdFinal = {"-i",  dir.getAbsolutePath()  + "/" + "inputVideo.mp4",
                "-filter_complex", "[0:v]reverse,fifo[r];[0:v][r] concat=n=2:v=1 [v]",
                "-map", "[v]",
                dir.getAbsolutePath() + "/" + "final.mp4"};