8K TV

Sat Apr 13 21:46:29 CDT 2013

Yeah, I can see the pixlelization and other artifacts in DTV broadcasts, but that is usually due to bit-starvation thanks to the stupid cable and satellite delivery companies.

Where are you seeing analog broadcasts?  Other than some low-power stations and translators, all television “broadcasters” are transmitting digitally with ATSC 8VSB DTV in the U.S.  Also, cable channels are all using digital transmission systems to cable headends.

There are LOTS of opportunities for the HD video to get totally hosed up between the original source and your set.  But, if you sat down and looked at true HD on even a decent quality TV (not high-end), you would be hard-pressed to find any artifacts.  It’s easy to justify throwing away a few unimportant bits here, and a few more unimportant bits there, until you are left with a marginal quality signal.  Then, that signal goes into a “statistical multiplexer”, which throws up when too many marginal HD signals want too many of the few remaining bits, all at once.

WARNING: DANGER WILL ROBINSON!!!  TECHNICAL INFORMATION AND JARGON FOLLOWS!!  READ AT YOUR OWN RISK.
The Fox broadcast network is the worst.  I don’t know if they still use it, but at one time they used a technique called stream-splicing at the affiliate stations to add local commercials, IDs, etc.  Most big-three network (ABC/CBS/NBC) stations decode the network A/V stream back down to baseband 1.5Gb/s or so (1080i or 720p), and then switch between HD sources at that baseband level.  That’s expensive.  Fox used a technique that kept the data stream at a lower bit rate (either mezzanine or actual 19.39Mb/s MPEG/ATSC), and tried to flash-cut by building additional MPEG II “I” frames at the switch point.  This technique was demonstrated early on in HDTV by Harris I think, but was deemed too unwieldy, prone to bad artifacts, and caused large variations of bits required.  Someone fixed most of the issues for Fox, and they built their whole network distribution system based on stream-splicing technology.  Interested parties can look up MPEG II and I, P, and B frames.  I can find out if Fox still uses this technology.  PBS is even more complicated.

Another problem is caused when a broadcaster wants to use “unused” transmission bits for a second, third, or more channels.  As long as the primary channel’s programming is either SD material, or HD content with little motion, that is OK.  But, if the primary contains fast motion (such as hockey or basketball games) in HD, many more bits are required.  If the broadcaster has “reserved” a certain amount of data payload for these other channels in their encoder’s stat-mux, the primary content WILL become bit-starved, and artifacts show up quickly.

Don’t get me started on cable companies.  They will take the primary channel bitstream, set a ceiling in a stat-mux, and then multiplex several HD signals on a single cable channel.  Too bad for you if the overall aggragation of bits is more than what they allow on a single cable channel.

As far as analog audio recording, I would rather listen to the very minor CD drum damage than listen to constant tape hiss, scratches, and distortion due to poor dynamic range.  I HATE constantly hearing hsssssssssssssss.  But, that’s my trade-off in life, and I’m glad that others think differently!

My oxygen-depleted speaker cables just came in, so I’m off to rewire my Mac.  No, not a computer Mac.
Terry, WB4JFI

From: Joseph Bento 
Sent: Saturday, April 13, 2013 8:57 PM
To: tacos at amrad.org 
Subject: Re: 8K TV

We have two TV sets in my house.  Both are CRT based, and both are over 10 years old.  One is HD capable.  However, I find analog broadcasts more realistic and natural.  There is something in the detail of most HD programming that somehow makes it look artificial, especially when there is fast movement in the characters.  That 'something' I really can't explain.  Similar to the percussion track on some CD's - the drums don't sound natural.  There's something a bit jarring in the sound.  That same irritant is not present on an all analog recording.

Joe, N6DGY

On 4/13/2013 6:02 PM, Andre Kesteloot wrote:

  On 4/13/2013 19:53 PM, Phil wrote:

    "…a whopping 16 times the picture resolution as today’s HD..." 

    Really? My tin eyes can rarely distinguish between a true HD broadcast and the same rendered in 'regular' resolution.

  Phil, 

  although 16 times better resolution appears a bit silly indeed, there is a marked difference in today's transmissions.
  In the early 1960s' we lived in Cambridge (UK) and watched British TV. It looked good enough for me (although was I had seen in 819 lines in France was definitely superior).

  Now, our channel 26 WETA transmits some old British programs (from tapes I presume)  and I must say that some of the Benny Hill re-runs definitely lack sharpness. (which, because of the content, hum hum, I sincerely deplore ...  :-)

  73
  André 

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