London Live

Not quite.

On Freeview HD the BBC use H264 encoders that dynamically switch between 25p and 50i encoding modes based on what they believe the input to be. I think they do it on a GOP basis. http://www.bbc.co.uk/blogs/researchanddevelopment/2011/04/software-upgrade-for-bbc-hd-on.shtml

You are right that all UK mainstream broadcasters TX from 1080/50i master suites, and the final point in the chain pre-encoding is a permanent 1080/50i signal (sometimes referred to as 1080i25) This can, of course, contain 25p content with no motion between the two interlaced fields (which is effectively segmented frame progressive) but the master tape or file is interlaced. (Some broadcasters also accept 1080/25p masters - I think Sky do - but they will be replayed with 1080/50i output)

The dynamic H264 encoder i/p switching is a function of the encoder and isn't flagged upstream. (When the BBC first introduced it - Sony TV sets went bonkers because Sony had only thought that i/p switching would happen on channel changes - if at all - and there was a sound disturbance when the i/p switch happened. And it happens a LOT on some content...)

When it comes to DSLRs and 1080/25p output. My understanding is that early models got very hot and started shutting down (and pixels died more quickly) because of the heavy processing required to process and down convert the chip output (which is much higher res than 1080p) to 1080p. Most cameras did this (and many still do) just by discarding lines and pixels, rather than filtering, which causes nasty moire. At the moment the only DSLR that is fully EBU approved is the Canon D1C ISTR.

It's an interesting choice to use Nikon DSLRs - but not sure that you really want to shoot news studios with shallow DoF, and if you don't go for that look, why not use something like low-end PMWs or similar cameras (which have the benefit of being able to be properly remotely controlled). I wonder how they will be racking their DSLRs and picture-matching them?

I suspect they won't be!

Do you think TV channels pilot for that long? Most shows I've been involved with will only do a couple of pilots for a format (across one or two days, a week at most).

If you are using VERY new technology and/or piloting a full channel with lots of shows from the same studio then you might do more - but you would be unlikely to pilot continuously for months. (Unless you are a VERY big broadcaster with the budget to match)

Why limited to 24Mb/s - surely they won't be recording in camera for their live output, and will be using live outputs from the cameras, which will be uncompressed?

For pre-recorded studio output, presumably they will be recording downstream of their vision mixer, so again will be recording an uncompressed SDI or HD-SDI output - and can chose whatever recording format they want.

Or are you talking about location acquisition? If so 24Mb/s HD AVC is probably not that terrible for an SD local news channel.

Be interesting to know what their studio and post infrastructure is based around in format and codec terms.

Just tuned into the DSat version on my Sky box...

Hmm... Burned out windows, and what look to be 25p pictures with quite a lot of shutter in them. Not exactly inviting lighting and camera set-up. Strange decisions on set/staging of interviews. Some money been spent on funky furniture, but looks like they're shooting it in a funky London furniture showroom, not a TV studio.

Looks a bit like student telly...

The Skype contributor looks better quality than the studio interviewer...

The location stuff I've seen looks fine. A bit DSLR-ey for a news channel - but a lot better than the studio stuff.

Of course PSB3 is coded by the Beeb, so ITV, UTV, STV, and C4 HD channels also have the dynamic p/i switching.

Arqiva code and manage COM 7, but I notice all the HD channels on there adopt the same dynamic p/i scheme as PSB 3

Is this switch the reason my USB tuner, at the start of idents and into the programme the voices sound very high pitched?

!!! Shouldn't affect the audio at all, although having said that, when the BBC started switching between p and i,
some Sony models produced a click everytime there was a switch (in theory as often as once every half second). That was fixed (eventually) by a software upgrade from Sony. Dunno, it's
possible your USB tuner is getting its audio and video timestamps messed up, but the switching doesn't and won't necessarily occur just at programme junctions

What tuner and what software are you using? It's only Freeview HD (not Freeview) that does this.

Can you get screengrabs?

I'll see what I can do assuming it's still showing something.

Video would be good. But anything is appreciated.