Php FFMPEG请求超时

I am using Laravel 4.2.

I am working on a project of uploading video. The uploaded video should be played in most devices that I am using php-ffmpeg package from the git-hub.

The requirement is the transcoding should be done in background. I am using WAMP 2.5.

What am I doing is, after upload I am firing an asynchronous ajax request that transcode the video and after successful completion it should insert a record into database containing video name, path etc.

The problem is if I upload a large size video, then I am facing error Maximum execution time of 120 seconds exceeded.

I know the possible solution is setting max_timelimit in php.ini but I don't think it is a feasible solution because if there will be larger video, the same error will occurred again.

Is there any technique that I can bypass this transcoding process in background?

My code is as below :

try{
            $video_id = Input::get('video_id');
            $video_path = Input::get('video_path');

            $path = '/video/'.date('Y').'/'.date('m');
            $path .= '/';
            $explode_filename  = explode("/",$video_path);
            $save_filename = $explode_filename[sizeof($explode_filename)-1];

            $ffmpeg = FFMpeg\FFMpeg::create(array('timeout'=>0));
            $video = $ffmpeg->open($video_path);

            $format = new CustomVideo();
            $format->setKiloBitrate(1000)
                    ->setAudioChannels(2)
                    ->setAudioKiloBitrate(256);

            $video->save($format, public_path().$path.$save_filename); 
            //saving video

            Video::where('id', '=', $video_id)->update(array('is_transcoded' => 1,'video_url'=>url($path.$save_filename)));
        }
        catch (Exception $ex){
           return Response::json (["Message"=>$ex->getMessage(), "code"=>$ex->getCode(), "trace"=>$ex->getTrace()]);
        }