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Obama looks like Blanka on European TV's. Is he black or green?
shardian:
--- Quote from: Blanka on January 21, 2009, 09:48:39 am ---
Who talks about blocky on THIS forum? I love blocky. Hey I play 8-bit pixelcrap all the time!
Only thing funny is that soccer looks like indoor fussball. The grass is too many little contrasty bits for the MPEG compression, so it gets a solid green area on DVB-T.
--- End quote ---
I've noticed on NFL games that the field turf crap looks odd in HD.
MonMotha:
--- Quote from: orion on January 21, 2009, 09:21:53 am ---"Chances are, the issues are the people converting it to PAL (assuming you're still using that archaic system) on your side of the pond."
I thought they were using DVB-T with COFDM modulation. Apparently COFDM is better than 8-VSB (which is what we use here in the US) particularly in dealing with multipath interference. I am not sure however what advantages/ disadvantages DVB-T offers vs ATSC. I only have a rudimentary understanding of all this, and am curious about it.
--- End quote ---
The following is rather technical babble. If you don't care, skip to the double space.
Yes, most European countries are now using DVB-T, though not all have gone exclusively digital yet, so the OP could be using PAL, and the OP specifically mentioned PAL.
DVB-T allows a couple different modulations. It seems that the europeans simply cannot agree on a TV standard (look at how many kinds of PAL there were). COFDM is by far the most common, and yes, it handles multipath better than 8-VSB. Some countries (Sweden comes to mind for some reason, but I could be totally off-base) use 16-QAM (similar to 256-QAM used by OpenCable in the USA, but with a less dense constellation) just to be different. 16-QAM doesn't really offer any advantages over COFDM.
I believe DVB-C (the DVB cable standard; USA uses OpenCable or one of numerous competing IPTV standards) uses 64-QAM or 256-QAM (provider's choice) with smaller QAM constellations also allowed but not commonly used due to throughput concerns, and DVB-S (satellite standard, used globally including by many major sat providers in the USA) uses QPSK or 8-PSK (again, provider's choice) with some more complicated PSK mechanisms allowed but not commonly used due to the cost of the required receiver. The modulation methods were chosen to maximize data rate on a given media while attempting to manage any shortcomings as effectively as possible.
There is also a DVB-H standard which is designed for mobile/handheld devices. They play some tricks with time division multiplexing to allow portables to shut their receiver off during much of the time to save battery.
The USA chose to use 8-VSB for its ATSC DTV standard because it covers rural areas slightly more effectively for a givne transmitter power. Of course, they managed to screw over all the city dwellers in the process with multipath and made it impossible to demod if the antenna is in motion, but by golly it covers the sticks better. The data format is roughly based on DVB which is itself based on MPEG2-TS.
ATSC also defines a 16-VSB standard, and I think all ATSC tuners are required to support it. 16-VSB gives you roughly double the data rate, but requires better SNR to demod. The use of 16-VSB would allow OTA 1080p60 broadcasts, but I'm guessing they'll just amend the standard to use h.264 or whatever the "codec du jour" is when they want to do it and continue using 8-VSB.
There is also an ATSC-M/H standard that is in early stages of development (and appears to have fizzled) to allow ATSC compatible transmissions which are capable of reception by a receiver in motion. I'm not aware of any implementations or even a complete working draft, but supposedly somthing exists and as of Dec. 1, 2008 is an official standard of the ATSC.
Yes, I know way too much about this stuff.
Techno-babble ends
Regarding image quality, the digital stuff in the USA universally looks better when it's done right (so basically anything but hooking composite NTSC up to an upconverting encoder). Football (talking American here, but the field is similar to Soccer) looks absolutely stunning. On Fox (720p), I can usually see blades of grass/turf. On CBS and NBC (1080i), the grass blades are visible during still scenes, but motion tends to macroblock and lose that level of detail. 1080i is just a little too much for ~19Mbps MPEG2 (and of course most stations run at least one more SD channel).
If you want to see simply stunning picture, find somebody who has a DigiCipher box and can pull the main CBS network feed. It's "megastream" MPEG2 (or was last time I checked), which is ~45Mbps. 1080i at 45Mbps looks really, really good (like Blu-Ray good just with interlacing artifacts).
For those europeans wondering since it came up, most US TV stations transmit 16:9 HD (either 720p60 or 1080i), but most stations still have 4:3 SD locally originated content. They just upconvert it to their HD frame and either "barn-door" (correct) or stretch (not correct) it. Those with 4:3 TVs either letterbox the picture or crop off the edges to "zoom" it to full-frame. Almost all TVs sold now are 16:9. Most stations run their main channel in HD (which will show network content and the local news and such) as well as one, two, or, rarely, three SD "subchannels". Common subchannels are 24-hour news, 24-hour weather, 24-hour weather radar, or sometimes a "lesser" network. While the standard allows for it, pretty much nobody runs two or more HD channels as the bitrates required to do it make the video look terrible with compression artifacts that are more objectionable than just running lower resolution video.
Regarding the original question, I suspect richms is at least partially right. There are like 10 common colorspaces in TV-style video land. All are similar, but most represent "tint shifts" of each other. Hence, if you treat values from one colorspace like they're from a different but similar one, people could look green (or purple). This would have likely been done by the people going from US video to European video (your field rate and resolution are still different even in digital land, so some "massaging" is necessary).
orion:
"I believe DVB-C (the DVB cable standard; USA uses OpenCable or one of numerous competing IPTV standards) uses 64-QAM or 256-QAM (provider's choice) with smaller QAM constellations also allowed but not commonly used due to throughput concerns, and DVB-S (satellite standard, used globally including by many major sat providers in the USA) uses QPSK or 8-PSK (again, provider's choice) with some more complicated PSK mechanisms allowed but not commonly used due to the cost of the required receiver. The modulation methods were chosen to maximize data rate on a given media while attempting to manage any shortcomings as effectively as possible."
So let me ask you, since I am obviously dealing with an engineer here... is this the reason why SD video looks like TOTAL crap on a high def set coming in from a satellite provider, while on the other had SD content only looks like crap on an HDTV coming in though cable? I think I have effectively ruled out (at least I'm not buying it) the whole "cheap built in upconverter" in the TV notion as to what causes that horrible graininess of SD signals on HD sets. I have tried a few stand alone upconverters and tried running a signal though a PC video capture card back to the set via DVI (trying different resolutions) to no avail... which leads me to suspect crappy compression techniques employed by the carriers. (Also DVD's.... even the non unconverted ones look pretty good on an HDTV)
"If you want to see simply stunning picture, find somebody who has a DigiCipher box and can pull the main CBS network feed. It's "megastream" MPEG2 (or was last time I checked), which is ~45Mbps. 1080i at 45Mbps looks really, really good (like Blu-Ray good just with interlacing artifacts)."
I used to work for a PBS station back in 99 and we had an HD demo set that we would set up at malls ect... to educate the public on this new HDTV phenomenon. Anyway the set was fed though some kind of HDTV VTR (the tape looked like a regular VHS tape) The picture on that looked absolutely stunning, almost 3-D, certainly better than anything I get over Sat. today.
MonMotha:
--- Quote from: orion on January 21, 2009, 02:37:11 pm ---"I believe DVB-C (the DVB cable standard; USA uses OpenCable or one of numerous competing IPTV standards) uses 64-QAM or 256-QAM (provider's choice) with smaller QAM constellations also allowed but not commonly used due to throughput concerns, and DVB-S (satellite standard, used globally including by many major sat providers in the USA) uses QPSK or 8-PSK (again, provider's choice) with some more complicated PSK mechanisms allowed but not commonly used due to the cost of the required receiver. The modulation methods were chosen to maximize data rate on a given media while attempting to manage any shortcomings as effectively as possible."
So let me ask you, since I am obviously dealing with an engineer here... is this the reason why SD video looks like TOTAL crap on a high def set coming in from a satellite provider, while on the other had SD content only looks like crap on an HDTV coming in though cable? I think I have effectively ruled out (at least I'm not buying it) the whole "cheap built in upconverter" in the TV notion as to what causes that horrible graininess of SD signals on HD sets. I have tried a few stand alone upconverters and tried running a signal though a PC video capture card back to the set via DVI (trying different resolutions) to no avail... which leads me to suspect crappy compression techniques employed by the carriers. (Also DVD's.... even the non unconverted ones look pretty good on an HDTV)
--- End quote ---
Not directly. The various mediums do now provide varying data rates, whereas with analog transmission, one channel was 6MHz worth of analog bandwidth for one channel. Due to the varying data rates, the providers will compress things more or less to cram what they want in.
Of course, quality of the encoders used also varies highly, and many cable/sat providers overcompress their SD channels in order to cram more channels in without having to upgrade their systems. Many sat providers also downres their 1080i HD to 1440x1080, but this isn't really noticeable to most viewers.
If you're talking about the locals in SD via sat, those are usually woefully overcompressed. They cram basically every single local channel from every market into the US onto a few sat transponders. At least your cable co only has to carry the stuff from your market.
Cable and satellite also often use different video codecs for HD, so you may be noticing the different types of compression artifacts.
That said, most TVs do have pretty terrible upscalers.
--- Quote from: orion on January 21, 2009, 02:37:11 pm ---I used to work for a PBS station back in 99 and we had an HD demo set that we would set up at malls ect... to educate the public on this new HDTV phenomenon. Anyway the set was fed though some kind of HDTV VTR (the tape looked like a regular VHS tape) The picture on that looked absolutely stunning, almost 3-D, certainly better than anything I get over Sat. today.
--- End quote ---
That would likely be D-VHS. It was popular around that time as it was the only standard "consumer grade" mechanism for putting HD video onto some form of portable media. DVHS used standard VHS tapes (although they were tagged in a similar manner to SVHS and were usually rather high quality media) to carry an MPEG2 stream similar to OTA broadcast. Bitrates were fairly high, so the picture was pretty good.
stace:
--- Quote from: Blanka on January 21, 2009, 01:20:08 am ---Last days a lot of Obama on the television. He is mentioned the first afro-american president. :afro:
But I wonder is he really black?
On our televisions he's always kind of green (no my TV is not bad, I see the same on all TV's here)
Are those americans still filming in NeverTheSameColour standard def cam's? And is it so hard to convert it to a decent PAL signal?
Please colour-manage your video Americans. It's not the Hulk you voted for I guess.
--- End quote ---
:banghead: :banghead: :tool:
Never had issues with PAL? Obama looked good here yesterday. But then I'm not in Europe, I'm in England !!! :cheers:
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