Create a video mosaic app

Project Description Need to create a unix cli using ffmpeg or gstreamer libraries which can merge multiple live streams and output single stream. Basically code will do equivalent work of using ffmpeg tool with complex filter example -filter_complex "nullsrc=size=640x480 [base]; [0:v] setpts=PTS-STARTPTS, scale=320x480 [left]; [1:v] setpts=PTS-STARTPTS, scale=320x480 [right]; [base][left] overlay=shortest=0:x=0 [tmp1]; [tmp1][right] overlay=shortest=0:x=320:y=0" The code should be able to handle adding and removing of input streams at runtime. Input will be two streams, for example if at start only one stream stream has data simply output that stream's data . Now if a second stream comes online app should be able to merge the two streams and use 50% of output video area for each stream and so on. Audio codecs support needed - AAC video codec - h264