@Override
public Result doWork() {
        shellCommand = new ShellCommand();
        ffmpegBinary = new String[] {
            FileUtils.getFFmpeg(context).getAbsolutePath()
        };
        command = concatenate(ffmpegBinary, command);
        CommandResult commandResult = getCommandResult(command);
        if (command`enter code here`Result.success) {
            onSuccess(videoPath);
        } else {
            onFailure(videoPath);
        }
    }
    //getCommandResult
    private CommandResult getCommandResult(String[] command) {
        try {
            process = shellCommand.run(command, null);

            if (process == null) {
                return CommandResult.getDummyFailureResponse();
            }
            checkAndUpdateProcess();
            return CommandResult.getOutputFromProcess(process);
        } catch(Exception e) {} finally {
            Util.destroyProcess(process);
        }`enter code here`
        return CommandResult.getDummyFailureResponse();
    }