[AnimalMuppet]

I actually have written software for video routers and character generators. We didn't consider them hard real time, though I wouldn't claim that such was standard industry usage.

For example, if you're doing a take, you have to complete it during the blanking interval, but usually the hardware guarantees that. In the software, you want you take to happen in one particular vertical blanking interval (and yes, it really is a frame-accurate industry). But if you miss, you're only going to miss by one. We didn't (so far as I know) specify guarantees to the customer ("If you get your command to the router X ms before the vertical interval, your take will happen in that vertical"), so we could always claim that the customer didn't get the command to the router in time. Again, so far as I know - there may have been guarantees given to the customer, but I didn't know about them.

But that was 20 years ago, back in the NTSC 525 days.

Nice name, by the way. Do you know of any video cards that will do a true Porter & Duff composite these days? I recall looking (again, 20 years ago) at off-the-shelf video cards, and while they could do an alpha composite, it wasn't right (and therefore wasn't useful to us).

[ajanuary]

I currently work on software controlling the hardware like video routers, and this is definitely my experience. It’s all very much soft real-time.

In terms of customers and how much they care, the North American market seems to care less than Europe.

[jcelerier]

I work on an open-source music sequencer (https://ossia.io) and no later than two days ago I had a fair amount of mails with someone who wanted to know the best settings for his machine to not have any clicks during the show (which are the audio symptoms of "missed deadline"). I've met some users who did not care, but the overwhelming majority does, even for a single click in a 1-hour long concert.

[littlestymaar]

If it's running in a consumer OS (not a RT one) and it counts on having enough CPU available to avoid missing the deadline, that's exactly what soft-realtime is.

Compare your “not a single click in an hour [for quality reason]” to a “not a single missed deadline in 30 years of the life expectancy of a plane, on a fleet of a few thousands planes [for safety reasons]”. That's the difference of requirements between hard and soft RT.

I did some soft real-time (video decoding) and I have a friend working on hard real-time (avionics) and we clearly didn't worked in the same world.

[AnimalMuppet]

Yeah. To me, hard real time is when you count cycle (or have a tool that does it for you), to guarantee that you make your timing requirements. We never did that.