Chromecast 50Hz support

There's now an option in Chromecast settings to force it to output 50Hz:

https://productforums.google.com/forum/m/#!topic/chromecast/Mj37qk5emKw

Finally!

That's excellent news, I can finally use NOW TV using the Chromecast as an alternative.

I had no issue changing my Chromecast to 50Hz. Casting Now TV, there is a massive improvement in PQ, although personally I think the LG NOW TV app has the best streaming quality (the set is connected via Ethernet), but it's a lot better than before.

No issues with All4 either, although when streaming Desmond's, it exposes the poor bitrate All4 uses to stream some of the older shows. However I'm looking forward to streaming the Walter Presents shows via Chromecast instead of the NOW TV box, which still outputs at 60Hz.

If you rent or buy from Google Play, the movies only output properly at 60Hz. I also had a similar issue with Netflix.

NOW TV is definitely 50Hz, even on American films.

That's exactly what you'd expect.

Amazon, Netflix, Google, Apple etc. are usually using 23.976p (aka 24p) masters for movies and drama, and will output them best at 60Hz with 3:2 pulldown. (Ideally there would be a 23.976/24Hz output - but there isn't). (Apple isn't universally 60Hz - ISTR some European stuff is 50Hz - but I may be wrong)

Now TV is an off-shoot of Sky, who will broadcast at 50Hz (23.976p content will have been sped up to 25p as 50i before, or on, delivery or ingest) as their master copies are likely to be 50Hz, so Now TV is best watched at 50Hz.

Personally I'd love to find a box that correctly output streaming video at the right refresh rate (including 24p stuff at 24p). There are a couple of solutions that almost do this - but they're not quite perfect.

I thought the whole issue with Now TV is was it was 60Hz?

The NOW TV box outputs at 60Hz, but as noggin explains, the output is at 50Hz, which means devices like the Chromecast can now render the service without any noticeable difference to the playback. This is also the case for BBC iPlayer, All4 and any European apps you can cast from.

Chromecast was originally designed for 60Hz, which is why Google and Netflix videos require you to switch back to it to watch properly.

You're confusing the set top box with the service.

The Now TV video streams are almost certainly 50Hz (as that's the format Sky SD and HD broadcasts on cable, satellite, terrestrial are, as are the streams on the Sky On Demand service).

The Now TV box - which is just one way of watching Now TV streams - is a cheap rebadged Roku job, and is running at a fixed 60Hz output. So all the Sky stuff is running with motion judder, as is iPlayer and any other 25/50Hz content played on the box.

If you watch Now TV on an Android TV device, or a PC, which has been configure for 50Hz output you'll get 50Hz streams displayed at 50Hz (which you can't do with the box that Sky sell...)

... (23.976p content will have been sped up to 25p as 50i before, or on, delivery or ingest) ... How is this speeding up achieved? I have trouble visualising it. I can visualise it with film on a telecine, but not a file!

If the media is delivered on HD Cam SR tape - as is still quite common - then there are options on some SR decks that allow 23.976p content to be played back at 50i with the deck handling the change of playback speed with pitch correction (you get a change of tempo on music, but not a change of key!) You can use this on ingest into your server playout system, or in a tape-to-tape dub to create a 50i HD Cam SR master.

If the media is delivered as a file then there are a number of approaches that can be adopted. Lots of editors have this issue - not just broadcasters - as increasingly content is distributed globally at 24p/23.976p but you need to edit it in a 50i/p production. Some will just drop it on the time line and pretend they can't see the repeated frames... Others will take it into Cinema Tools which lets you edit the metadata of the file to effectively convince the editing package that it is actually a 25p file not a 24p file (though this does mean the audio is then out of whack - but you can handle that separately with a pitch conversion), whilst other solutions will do a decode and recode with a 1:1 frame mapping and handle the audio conversion too.

One of these two routes is how I'd expect a 50i master to be delivered from a 24p source these days.

Noggin - thanks for the detailed explanation, makes sense to me now.