With 2 IR receivers the configuration is a bit tricky.
Your "* * avermedia_remote" rc_maps.cfg will configure both the gpio-ir receiver and the receiver on your DVB dongle to decode the signals of your remote. One possibility is to change the file so that only the gpio-ir receiver is configured:
Another thing to keep in mind is that it's not guaranteed that the gpio ir receiver will always be the first IR device (check the output of "ir-keytable"). If you manually run ir-keytable to change the config it'll apply the settings to the first rc device (rc0) unless you explicitly change that with the "-s" option.
The automatic configuration run by the udev rules take care of that, ir-keytable -a will be run for all your IR receivers with -s set appropriately - so that rc_maps.cfg is applied to all IR receivers on your system.
So, better remove the ir-keytable call from your autostart.sh.
Instead of covering the IR receiver with black or aluminium tape it'd be better to blacklist the the driver for the IR receiver in your DVB dongle - or just use the IR receiver in your DVB and not add gpio-ir. With only one receiver life's a lot easier
so long,
Hias