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Is there HD and HD?



 
 
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  #11  
Old July 23rd 15, 09:06 PM posted to uk.tech.digital-tv
critcher[_5_]
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Posts: 60
Default Is there HD and HD?

On 23/07/2015 15:03, Chris J Dixon wrote:
PeterC wrote:

I've noticed a couple of things with (Freesat) HD:

On, e.g., Countryfile, the pieces to camera during intros and in buildings
are good; the pieces 'out in the countryside' seem almost like upscaled SD
at best

When deleting an HD recording, an hour from BBC goes more quickly than the
same from C4 or ITV. This suggests a difference in file size. I haven't
really quantified it, but it's noticeable.


When HD first appeared, there was more than a little concern
about programme content which had been "artistically" manipulated
with various techniques such as "filmic" effects, thus negating
some of the supposed advantages of HD.

The official response was along the lines of "We know best, and
we don't necessarily want all HD to look the same."

Personally, I would prefer to make any adjustments at my end, in
the same way that I can adjust tone controls to my own
preference.

Chris




I don't understand the point in making programs in HD when they are
covered in misty effects to make then look period.
  #12  
Old July 23rd 15, 10:51 PM posted to uk.tech.digital-tv
PeterC
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Posts: 790
Default Is there HD and HD?

On Thu, 23 Jul 2015 14:34:36 +0000 (UTC), Richard Tobin wrote:

In article ,
NY wrote:

I've now made test recordings: a 5-minute recording from BBC One HD is 208
MB and a 5-minute one from ITV1 HD is 162 MB. VideoRedo says that the bit
rates are 5.7 and 4.5 Mbps respectively.


This is for terrestrial rather than satellite, but the principle is probably
the same though the figures will differ


I seem to recall it being said here some years ago that it was the
other way round for satellite because the BBC's principle of "platform
neutrality" prevented it from making use of the relatively cheap
satellite bandwidth to provide better quality than terrestrial.

-- Richard


That's what my rough method suggests.
--
Peter.
The gods will stay away
whilst religions hold sway
  #13  
Old July 23rd 15, 10:57 PM posted to uk.tech.digital-tv
Andy Furniss[_3_]
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Posts: 130
Default Is there HD and HD?

Scott wrote:
On Thu, 23 Jul 2015 15:03:07 +0100, "NY" wrote:

"PeterC" wrote in message
...
I've noticed a couple of things with (Freesat) HD:

On, e.g., Countryfile, the pieces to camera during intros and in
buildings are good; the pieces 'out in the countryside' seem
almost like upscaled SD at best

When deleting an HD recording, an hour from BBC goes more quickly
than the same from C4 or ITV. This suggests a difference in file
size. I haven't really quantified it, but it's noticeable.


I've only just got a DVB-T2 USB adaptor for my Windows Media Centre
PC, so I've not had chance to make many recordings yet to compare
file sizes, but I know that what you say is true with SD:
recordings from BBC channels are larger than those from ITV1/CH4,
despite being the same resolution. Obviously recordings from Drama,
Yesterday and (at some times of day) ITV3 are smaller still, but
they use lower resolution 544x576 rather than 704x576.

I think that, for the same resolution, ITV compress their data to a
lower bit rate.


Which is the opposite of what OP is reporting !


For HD DVB-T2 AFAIK the BBC code the main mux that contains ITV1 HD and
BBC1 HD. Sizes are likely to be related to content for these. Other DVB
T2 muxes are Aquiva. I don't know whether the different providers get
different rates or if it it just a stat mux.

For DVB S2 I don't know how the channels vs muxes are. It's possible
that the BBC (as noted in this thread) limit to match T2, but ITV/Others
may not do that.

  #14  
Old July 23rd 15, 11:31 PM posted to uk.tech.digital-tv
Andy Furniss[_3_]
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Posts: 130
Default Is there HD and HD?

Andy Furniss wrote:
Scott wrote:
On Thu, 23 Jul 2015 15:03:07 +0100, "NY" wrote:

"PeterC" wrote in message
...
I've noticed a couple of things with (Freesat) HD:

On, e.g., Countryfile, the pieces to camera during intros and in
buildings are good; the pieces 'out in the countryside' seem
almost like upscaled SD at best

When deleting an HD recording, an hour from BBC goes more quickly
than the same from C4 or ITV. This suggests a difference in file
size. I haven't really quantified it, but it's noticeable.

I've only just got a DVB-T2 USB adaptor for my Windows Media Centre
PC, so I've not had chance to make many recordings yet to compare
file sizes, but I know that what you say is true with SD:
recordings from BBC channels are larger than those from ITV1/CH4,
despite being the same resolution. Obviously recordings from Drama,
Yesterday and (at some times of day) ITV3 are smaller still, but
they use lower resolution 544x576 rather than 704x576.

I think that, for the same resolution, ITV compress their data to a
lower bit rate.


Which is the opposite of what OP is reporting !


For HD DVB-T2 AFAIK the BBC code the main mux that contains ITV1 HD and
BBC1 HD. Sizes are likely to be related to content for these. Other DVB
T2 muxes are Aquiva. I don't know whether the different providers get
different rates or if it it just a stat mux.

For DVB S2 I don't know how the channels vs muxes are. It's possible
that the BBC (as noted in this thread) limit to match T2, but ITV/Others
may not do that.


Looking at the main HD T2 mux currently and it's running with 13 (out of
40) mbit spare. Maybe night is not the best time to look.

  #15  
Old July 24th 15, 08:45 AM posted to uk.tech.digital-tv
R. Mark Clayton[_2_]
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Posts: 574
Default Is there HD and HD?

On Thursday, 23 July 2015 15:04:50 UTC+1, NY wrote:
"PeterC" wrote in message
...
I've noticed a couple of things with (Freesat) HD:

On, e.g., Countryfile, the pieces to camera during intros and in buildings
are good; the pieces 'out in the countryside' seem almost like upscaled SD
at best

When deleting an HD recording, an hour from BBC goes more quickly than the
same from C4 or ITV. This suggests a difference in file size. I haven't
really quantified it, but it's noticeable.


I've only just got a DVB-T2 USB adaptor for my Windows Media Centre PC, so
I've not had chance to make many recordings yet to compare file sizes, but I
know that what you say is true with SD: recordings from BBC channels are
larger than those from ITV1/CH4, despite being the same resolution.
Obviously recordings from Drama, Yesterday and (at some times of day) ITV3
are smaller still, but they use lower resolution 544x576 rather than
704x576.

I think that, for the same resolution, ITV compress their data to a lower
bit rate.


IIRC BBC broadcasts in QAM16 and ITV etc. in QAM64. This may explain why the raw files are different sizes.
  #16  
Old July 24th 15, 08:58 AM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
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Posts: 2,210
Default Is there HD and HD?

On Thu, 23 Jul 2015 21:06:59 +0100, critcher
wrote:

I don't understand the point in making programs in HD when they are
covered in misty effects to make then look period.


I suppose there's a sort of half-baked argument that foggy, grainy,
wishy-washy or monochrome pictures can enhance the realism of a scene
if they could be regarded as as real photography that has survived
from the period in which it's set, but it makes no sense at all of
course if this is before photography was invented.

Rod.
  #17  
Old July 24th 15, 04:04 PM posted to uk.tech.digital-tv
Mark Carver
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Posts: 7,608
Default Is there HD and HD?

On 24/07/2015 08:45, R. Mark Clayton wrote:


I think that, for the same resolution, ITV compress their data to a lower
bit rate.


IIRC BBC broadcasts in QAM16 and ITV etc. in QAM64. This may explain why the raw files are different sizes.


All T1 muxes have run at 64QAM ever since DSO, so all five so called SD
muxes each have a payload of around 24 Mb/s

The T2 muxes, run at 256QAM, and have a payload of about 40 Mb/s



--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #18  
Old July 24th 15, 05:15 PM posted to uk.tech.digital-tv
Andy Furniss[_3_]
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Posts: 130
Default Is there HD and HD?

Mark Carver wrote:
On 24/07/2015 08:45, R. Mark Clayton wrote:


I think that, for the same resolution, ITV compress their data to a
lower
bit rate.


IIRC BBC broadcasts in QAM16 and ITV etc. in QAM64. This may explain
why the raw files are different sizes.


All T1 muxes have run at 64QAM ever since DSO, so all five so called SD
muxes each have a payload of around 24 Mb/s


Yes, well, apart from the three that are 27 :-)

code rate
2/3 = 24
3/4 = 27

  #19  
Old July 24th 15, 05:37 PM posted to uk.tech.digital-tv
Paul Ratcliffe
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Posts: 2,476
Default Is there HD and HD?

On Fri, 24 Jul 2015 00:45:49 -0700 (PDT), R. Mark Clayton
wrote:

I think that, for the same resolution, ITV compress their data to a lower
bit rate.


IIRC BBC broadcasts in QAM16 and ITV etc. in QAM64. This may explain why the raw files are
different sizes.


What Mark said, plus, modulation scheme and FEC have no effect on the
data rate used (they only define the capacity limit) and therefore on the
file size.
So it explains nothing in this case
  #20  
Old July 24th 15, 05:40 PM posted to uk.tech.digital-tv
Paul Ratcliffe
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Posts: 2,476
Default Is there HD and HD?

On Fri, 24 Jul 2015 12:24:28 +0200, Wolfgang Schwanke wrote:

I don't understand the point in making programs in HD when they are
covered in misty effects to make then look period.


Film scratch effects and jumpy motion are pointless in any definition.


The stupidity of media types wanting to make things look 'old'.
I've seen things aged after only a couple of minutes (on sport usually).
It always strikes me as completely ****ing stupid, but I'm not an arty
farty director/producer type.
 




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