[PorterDuff]

I take it that scarcely anyone here has written software for video switchers, routers, DVEs, linear editors, audio mixers, glue products, master control systems, character generators, etc. etc. Missing a RT schedule rarely results in death, but you'd think so given the attitude from the customer. That's a silly definition for it.

There's a whole world out there of hard real time, the world is not simply made up of streaming video and cell phones.

The cool thing on HN is you can get down voted for simply making that observation. It's a sign of the times I'm afraid.

[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.

[fastball]

You just agreed with the OC.

RT video/audio failing never results in death. Where as failures in "avionics, industrial control" absolutely can / do. That seems to be where OC was drawing the line.

[detaro]

Seems to be a common distinction, although GP is right with the addition that the production side of things is more demanding (and at least would suffer financial damage if problems occur to often) than the playback side formed by random consumer gear, and has some, especially low-level/synchronization-related, gear to hard standards. But often soft is enough, as long as it's reliable enough on average.