...or it could be that it's something to do with multistream. Same problem on both Edision and Octagon.
I'll do some checks on French mulitstreams later. It may be something specific to RAI.
I've just discovered that both boxes see each other's recordings on a USB stick. That's quite useful.
The sun came out for a minute so I tried RAI
It's what they put in the transport stream that matters. The box just records the whole lot.
Das Erste has subtitles encoded as both dvb_subtitle and dvb_teletext. RAI only has dvb_teletext. If you look at the teletext on RAI, the subtitles are supposed to be on 777 and 778 for italian and english.
I can't find anything that will display dvb_teletext subtitles. ffmpeg can theoretically do it but none of my media players bother.
In the old days of CRT TVs with scart the box would put the teletext back into the VBI and the TV would decode it. My Hauppauge DEC3000S did that. But that's not possible with HDMI so now they have to overlay it on the picture.
The upstream software for the NationalChip GX6611 is obviously common to both boxes. I'll be interested to see if people can cross flash the software.