#!/bin/bash
USER="test"
PASS="test"
INPUT_1="http://$USER:$PASS@tvserver:9981/play/stream/channel/de2e410b91ff197fe4d38b0525886203"
INPUT_2="http://$USER:$PASS@tvserver:9981/play/stream/channel/a5eacd0f4295417f655690476e7c1123"
INPUT_3="http://$USER:$PASS@tvserver:9981/play/stream/channel/9adac0341f65a4e9510316d6a3711eca"
INPUT_4="http://$USER:$PASS@tvserver:9981/play/stream/channel/8fc57fd39d924458db986c5dd597bf0d"

ffmpeg -i $INPUT_1 -i $INPUT_2 -i $INPUT_3 -i $INPUT_4 -filter_complex "nullsrc=size=640x480 [base]; [0:v] setpts=PTS-STARTPTS, scale=320x240 [upperleft]; [1:v] setpts=PTS-STARTPTS, scale=320x240 [upperright]; [2:v] setpts=PTS-STARTPTS, scale=320x240 [lowerleft]; [3:v] setpts=PTS-STARTPTS, scale=320x240 [lowerright]; [base][upperleft] overlay=shortest=1 [tmp1]; [tmp1][upperright] overlay=shortest=1:x=320 [tmp2]; [tmp2][lowerleft] overlay=shortest=1:y=240 [tmp3]; [tmp3][lowerright] overlay=shortest=1:x=320:y=240" -c:v libx264 output.mkv