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BBC 1 HD Picture Quality - Any views?
On Fri, 5 Nov 2010 16:24:49 -0000, "David" wrote:
If the material is good and better than the SD standards will it come out in HD? Cinema films being a good example if the BBC actually use 35mm cinema film or do they use some cheaper vehicle with poorer quality to equate to the lower standards of SD? I understand the question, but I don't know the answer. -- Peter Duncanson (in uk.tech.digital-tv) |
BBC 1 HD Picture Quality - Any views?
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BBC 1 HD Picture Quality - Any views?
On Friday, November 25th, 2010 at 17:26:27h +0000, Peter Duncanson wrote:
I do agree that it would be a good thing if they could indicate which material is real HD. Exactly -- and the best promotion to those still on SD, would at the start of each HD program to have the classic style caption *** In HD where available *** at the bottom of the screen. |
BBC 1 HD Picture Quality - Any views?
"Richard Russell" wrote in message ... On Nov 5, 12:34 am, "j r powell" wrote: The above post contains no mention of lossy compression and low bitrates, Why should it? The OP was reporting that the quality was about twice as good. The OP said BBC1 HD "should be miles better to be true HD". The controversy over last year's BBC HD bitrate reduction is well-known - it was even raised on a BBC TV "points of view" programme because so many viewers were complaining. I therefore fail to see why low bitrates should not play a part in the broadcasts meeting the OP's expectations of "true HD". That's what one would expect if degradation from the lossy compression on HD was no greater (relatively speaking) than that on SD, and therefore not an issue." Who said that "the lossy compression on HD is no greater (relatively speaking) than that on SD"? If this was the BBC's intention - ie. someone said "Just increase the number of pixels on the HD services - retain the same relative level of compression loss per-pixel." then that in itself should be questioned, because we all know that the bitrates used for digital SD marked a huge step down in quality from the previous analogue system of "25 full uncompressed frames per second" (RIP). In other words, the SD compression policy doesn't do justice to true 576i, so why should the same policy do justice to true 1080i? Afaik however, even the current BBC1 "almost HD" service has more than twice the bitrate of its SD counterpart, and MPEG4 is more efficient than MPEG2. Ofc the increased number of pixels places higher demands on the HD services' compression codecs, but personally I still find it a welcome "escape" from digital SD. To talk about one being "twice as good" as the other however, is imho a gross oversimplification, unless it's backed by some research? Who's to say, for example, that the relationships between increased number of pixels and perceived picture quality, or between increased bitrate of a given compression codec and perceived picture quality, are linear? If the OP had said the quality was significantly *worse* than twice as good as SD then maybe those factors would have been relevant, but he didn't. Only if the above-mooted policy was in place and being adhered to. I'm not a BBC employee. Never said you were. I know you've been one in the past though. jamie. -- |
BBC 1 HD Picture Quality - Any views?
On Nov 5, 10:14*pm, "j r powell" wrote:
we all know that the bitrates used for digital SD marked a huge step down in quality from the previous analogue system of "25 full uncompressed frames per second" (RIP). "We" know nothing of the sort. You simply can't make a crude comparison like that, because the kinds of defect in the two systems are so dissimilar. How, for example, can you compare cross-colour (a major 'compression artefact' of your so-called 'uncompressed' analogue system, at least when decoded on domestic equipment) with MPEG artefacts? Also, the quality of analogue PAL by the time it actually reaches the viewer is often far worse than it was leaving the transmitter, whereas with digital transmission that isn't true. When the source material is 'MPEG-friendly' (Antiques Roadshow is a good example) the picture quality on DTT is better than it is with 'perfect' PAL. With some difficult material (e.g. lots of uncorrelated motion, as in some sports) DTT may be subjectively poorer quality than PAL. Analogue PAL isn't 'RIP' here (and won't be for another year) so I could choose to watch the main five channels in PAL if I wanted to. Instead I choose to watch them via DTT because most of the time the subjective quality is higher (and I'm one of those unfortunate people who see defects others don't, having been sensitized to them). Richard. http://www.rtrussell.co.uk/ |
BBC 1 HD Picture Quality - Any views?
"Richard Russell" wrote in message
... On Nov 5, 10:14 pm, "j r powell" wrote: we all know that the bitrates used for digital SD marked a huge step down in quality from the previous analogue system of "25 full uncompressed frames per second" (RIP). "We" know nothing of the sort. You simply can't make a crude comparison like that, because the kinds of defect in the two systems are so dissimilar. How, for example, can you compare cross-colour (a major 'compression artefact' of your so-called 'uncompressed' analogue system, at least when decoded on domestic equipment) with MPEG artefacts? No offence, but don't lecture me about crude comparisons when your previous post contained the mother of all of them. I knew you'd hook onto the lossy PAL colour encoding issue, and I nearly made reference to it for that reason, but my hope was to avoid going over stuff which both of us know already "for the sake of argument". I realise that PAL colour was lossy, but the replacement SD digital transmissions have colour space limitations as well - it doesn't even come close to true RGB, and imho "true PAL" beat it by a considerable margin as well. As for the PAL combing artefacts, they are considerably minimised in real-world scenes on quality "true PAL" sources, because these natural scenes tend not to contain sharp colour transitions. Sitting a reasonable distance away from an average CRT screen, you barely saw them at all. What you *did* see were vibrant colours, perfect motion tracking with no added blur or loss of subtle movements, details like surface textures being clearly defined, and images which were free of pixellation. You could also watch dark nighttime scenes without the dark backdrop disappearing into a black "zero definition" MPEG mush. Also, the quality of analogue PAL by the time it actually reaches the viewer is often far worse than it was leaving the transmitter, whereas with digital transmission that isn't true. Most people in the UK had great analogue reception - a relative minority didn't. Of these, most could have solved this by investing in a decent aerial had they given a monkeys about it. The existence of said minority and misguided desire to "make everyone have the same" was no reason to force everyone onto an inferior delivery system. In any event, digital has brought with it a new set of reception problems and replacement aerials etc. are still needed. When the source material is 'MPEG-friendly' (Antiques Roadshow is a good example) the picture quality on DTT is better than it is with 'perfect' PAL. With some difficult material (e.g. lots of uncorrelated motion, as in some sports) DTT may be subjectively poorer quality than PAL. Analogue PAL isn't 'RIP' here (and won't be for another year) so I could choose to watch the main five channels in PAL if I wanted to. Instead I choose to watch them via DTT because most of the time the subjective quality is higher (and I'm one of those unfortunate people who see defects others don't, having been sensitized to them). I'm not sure what modern day analogue quality is like in your region, but you obviously never saw the blurred mess which Winter Hill carried on analogue for its final 10 years of transmission - for all intents and purposes BBC analogue was very much RIP here in August of 1999. Whichever analogue transmitter you're watching, remember that any non-progressive/pulldown content shown in 14:9 or 16:9 letterbox will have been processed through an ARC which applies a lossy deinterlace-rescale-reinterlace process (just like upscaled SD on HD channels), so even if the programme source were uncompressed video (which it won't be) sent directly to the transmitter in uncompressed form (pigs might fly) then the ARC alone is going to mess up the picture quality. Anyway, congrats on successfuly changing the topic from "BBC HD bitrates are too low" to "digital is better than analogue so shut-it" without answering any of the points I raised in my last post. You'd make a good puppet politician. jamie. -- |
BBC 1 HD Picture Quality - Any views?
On Fri, 5 Nov 2010 04:49:55 -0700 (PDT), Richard Russell
wrote: On Nov 5, 11:20*am, Alan wrote: Pre August 2009 the quality was absolutely stunning. Post August 2009 it's just a bit better than SD. I understand the purpose of hyperbole, but you know very well that the difference was not as great as that. For a lot of typical material the subjective quality pre- versus post- bitrate/encoder changes was pretty much indistinguishable. For some highly testing material the quality fell. Bloody 'ell, have DN or AQ admitted that? If you still worked there you'd probably have been carpeted for saying that. |
BBC 1 HD Picture Quality - Any views?
"Geoff Berrow" wrote in message ... I'm saying that Autumnwatch Unsprung, which is shot with a few of redheads in a makeshift studio and hand held cameras is significantly better than the studio shots on the flagship BBC News programme which one might reasonably expect to be shot in HD. that's because the bbc news isn't HD. seems the bbc 1 hd channel has the logo whether they are airing sd or hd - unlike say itv hd or channel 4 hd who keep the logo for the HD stuff. -- Gareth. that fly...... is your magic wand.... http://dsbdsb.mybrute.com you fight better when you have a bear! |
BBC 1 HD Picture Quality - Any views?
"Richard Russell" wrote in message ... There will be a lot of SD on BBC1 for a long time. Even some prestige programmes like Merlin are not made in HD, because the CGI would be too expensive. And what about repeats? You can argue about when there's enough HD content to justify starting a 'BBC1 HD channel', but there will always be a proportion of SD on it. with the sky hd program guide at least, HD shows are indicated by being listed in a different colour - maybe freesat and freeview program guides should try doing something similar to avoid confusion. -- Gareth. that fly...... is your magic wand.... http://dsbdsb.mybrute.com you fight better when you have a bear! |
BBC 1 HD Picture Quality - Any views?
The dog from that film you saw wrote:
with the sky hd program guide at least, HD shows are indicated by being listed in a different colour - maybe freesat and freeview program guides should try doing something similar to avoid confusion. Actually none of this should be required, it's rather sad that whether a programme is in HD or SD needs to be flagged at all, it should be bloody obvious when watching it ! -- Mark Please replace invalid and invalid with gmx and net to reply. www.paras.org.uk |
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