Sky to close 8 box office channels

Stop stinking the forum with your sourceless posts!

Oops - so why aren't broadcast pixels square? Anyway, did anyone seen the BBC's coverage of the proms on BBC 1 last night?
I believe it was filmed in HD - to be more precise, 720p, and then converted into SD for transmission. I was watching it on digital satellite, and then switched to a near-perfect analogue signal I receive from Crystal Palace. It was breathtaking. The amount of detail was just amazing. I could actually see sweat on the pianist's hands! I didn't realise that PAL is capable of so much.
I suppose the quality of source material has always prevented the format from being pushed to its limits.

See - you can type half decent if you take your time.

HD isn't just from Sky - it's already happened over in Yankland.

HD-TV is a new universal brodcasting format which is set to replace standard TV at some point in the distant future. It is a format which displays images at a larger resolution than PAL, NTSC, and SECAM, in one format at dffering resolutions which should work on all HD compatible TVs.

As TV Screens have gotten bigger, the higher resolution will provide better quality, and alot more details. Also the transmission stream uses more bandwith which should reduce blurs and pixelation, as well as remove issues of colour signals and fidelity.

Alot of films have been prepped for HD, and major events as well as TV Films, Dramas etc have been using HD equipment to ensure content is ready.

Also, Japan and America were the first to adopt the new format, and Europe wont benefit until broadcasters, hardware manufactuers and programme suppliers increase their HD content which will drive down prices. BBC, Discovery, Sky are the first to make plans and preperations for the new HD format, its the same with digital, it didnt become popular until it was affordable and the content arrived, except we led Digital TV, and now we have fallen behind Japan and USA...

What he said. Thanks Martin for finally explaining.

Although I'm not a subscriber to the fact that because something's new it's better. We're still coming to terms with a stable sustainable DTT system in this country - and even on there +1 and shopping channels are being crammed in at the expense of quality. HD will be good, but like 625line and widescreen will be phased in gradually. Im sure we can continue watching SD for the next decade or so.

Because there is no reason for them to be square!

The actual reason is that standard def digital TV is based on a fixed sampling rate of 13.5MHz for the luminance and 6.75MHz for the chrominance if standard 4:2:2 sampling is used. This is the same for both 525 and 625 (aka 480 and 576 active) TV standards - and was chosen after a lot of research. A UK "PAL" analogue TV line is 52us active, 64us total, and thus contains 702 active luma samples at 13.5MHz (351 chroma samples at 6.75MHz) To allow for a bit of leeway 720 luma samples are actually used (360 chroma).

This is the case for both 4:3 and 16:9 video - the samples/pixels are different widths in the two different formats, and in neither case square. (The 702x576 image is 4:3 or 16:9, the 720x576 is slightly wider than 4:3 or 16:9)

From memory 13.5MHz is also quite close to being 4x3.58, meaning it is close to being 4fsc NTSC (i.e. 4 times the composite chroma subcarrier for NTSC) Of course it is nowhere near the 4fsc of PAL 4.43...



All of the Proms this year have been shot in HD, and all the proms last year were shot by the same HD cameras (though the HD mixer was only commissioned for the last night last year). Later with Jools Holland is also shot on the same cameras (they park the same OB unit at TVC) as are some sporting events and Songs of Praise. The same truck was also at Glastonbury this year - along with other HD units bought in (last year there was also HD at Glasto) - and Live 8 was also shot in London/

The cameras are Sony 1080/50i models (not 720/50p) - and AFAIK the Proms are shot 1080/50i because Discovery HD in the US annd NHK in Japan are both buying the concert coverage and they are 1080/60i broadcasters. (They'd rather have 1080o than 720p)

(Last I hear the Beeb hadn't made a choice about BROADCAST HD standards, but at the moment pretty much all HD production is either 1080/50i or 1080/25p in-house. The HD OB cameras are 1080/50i only AIUI - though newer Sony cameras can capture 1080/50p and scale this to 720/50p internally, whereas the ones the Beeb have are 1080/50p internally, but output 1080/50i which would need to be de-interlaced and scaled to create 720/50p)

Pretty much all high-end music and arts coverage (apart from some stuff shot at the Barbican) on the BBC has been HD for a while - Proms, Carols from Kings, Covent Garden Opera and Ballet etc. The Viennese New Years day concert is also HD.

HD source pictures downconverted to standard def still look a lot better than standard def cameras - the video noise, aperture correction/edge enhancement etc. are all at the HD level, so less obvious when converted to SD (whereas they will be more obvious in SD cameras as they are SD level in them and not average away). Also - the sharper the source material, the cleaner the result. Just as a good 35mm film transfer can look excellent in PAL, so can a good HD downconversion.

HDTV is not a new technology it has been around for 15 years if your looking at a computer monitor your using it right now HDTV is not a new standard all that it gives you is higher refresh rates and screen resolutions, why should i have to pay up to £2K for something i have had for years on my PC

Sorry - missing something here - Higher refresh rates? Higher resolutions? Nice - bout time TV behaved like a computer screen. Sounds like a new standard for TV viewing to me.

Ween2K - don't happen to have an alter ego who's name sounds like a telephone number do you? Both from Scotland, both have trouble typing, both the mental age of a turnip....

3 points;

What is the mental age of a turnip (perhaps 32)
How can it be a new technology if everyone has been using it for years
Why dont you do something else with your sad little life instead of dishing out pointless insults and telling people they are bad at being disabled

Thanks Noggin, thats a really good pointer to how things are now and very clearly shows where they are going.

: If 1080/50p becomes the standard for camera internals, then equipment refreshes will lead to the point where a large proportion of (higher value) content is imaged at this rate, if not captured in it. If capture rates then moved up to store 1080/50p then what could be the future for a capture standard, and indeed the common interface standard?
I'm assuming that SDI wouldn't survive if it were required to handle the sort of bit-rates demmanded by uncompressed 1080/50p, and that capture devices would hold 1080/50p in a compressed form - possibly MPEG-4?

It already is the standard for CCD camera intentals on 1080 line cameras - as it has been for 576 SD and 480 SD cameras since we went CCD really. This is because most CCDs, AIUI, have progressively scanned sensors, the interlace is derived by averaging lines.

The difficulty - at the moment - is distributing and recording 1080/50p and 1080/60p. There are some VTRs that will record this higher bandwith format - but broadcast kit like routers, Vision mixers, DVEs etc. are connected using HD-SDI which maxed out at 1.5Gbps, and 1080/50p and 1080/60p need more than this for interconnection. Either you have to use compression - as the BBC has proposed (they demo-ed mezzanine 2:1 compression for interconnects - adding only a few lines of delay - earlier this year at their open day) - or you have to use 2 HD-SDI interconnects for each source and destination.

This isn't at a viable stage yet for production.
[/quote]
I'm assuming that SDI wouldn't survive if it were required to handle the sort of bit-rates demmanded by uncompressed 1080/50p, and that capture devices would hold 1080/50p in a compressed form - possibly MPEG-4?[/quote]
SDI is 270Mbs and standard def only. There is already a different standard for HD, which is HD-SDI, which allows for a max of 1.5Gbps, which allows 720/50p & 60p and 1080/50i and 60i but not 1080/50p or 60p.

As mentioned above - HD-SDI could carry lightly compressed 1080/50p or 1080/60p - but there is no common interface standard for this yet - and so it isn't possible.

You wouldn't want to use any system of compression for interconnection that added anything more than a few lines of delay - as the last thing you want to add is frame delays that far up the production chain.

MPEG2 and MPEG4 only deliver high efficiency for encoding if you use long-GOPs, which whilst fine for distribution (either for broadcast or pre-recorded releases) - aren't suitable for broadcast VTR or server applications - where short GOPs for low numbers of frames being grouped are the solution.

Once you try and go much over 5:1 compression in a VTR you start to have problems. (Even MPEG2 based VTR/VDR formats like IMX and IMX on XDCam, or Beta SX, only use 1 frame I-frame only or 2 frame GOPs)

Hence my inverted commas around the word "new". In terms of domestic broadcast television it certainly is new. As a technology proper, it isn't.