Film Stock

Sarah: "So anything shot on 35mm/16mm film has to be converted into digital
for transmission/
DVD release, but both the Digibeta and HD
are "filmed" directly onto a digital format - in other words, they
don't use film?
Why the uproar? :-)"

Aesthetics and quality.
Film in the 1960s had to be telecinied to PAL, NTSC or SECAM video
depending on where in the world it was shown, however we are fortunate
that the decision was made to shoot UFO and the other ITC series of the
period on film. If they hadn't then we would be looking at images
similar to those of Patrick Troughton era Doctor Who.

Although the quality of film and digital video have converged, they do
have aesthetic differences due to things like film's wider range of
exposure, colour space and shallower depth of field.
Of course much of this isn't consciously apparent to a general audience
on a small screen but there is an unconscious effect and HD can still
struggle at times not to look like superior home video.

Personally I find the most irritating artefact of much which is shot on
HD is........ (SKIP THE REST OF THE PARAGRAPH IF YOU DON'T ALSO WANT TO
BE IRRITATED EVERY TIME YOU SPOT IT) ... the way that often the images
look OK when everything is at rest but as soon as the camera moves (or
actors if they are large in frame), then it becomes Smear-ovision.


Torchwood is one fairly egregious example. Despite being shot on HD it
manages to look cheaper and nastier visually than the current Dr Who,
which is shot in standard-def PAL Digibeta.

Regards
John

Plse forgive my ignorance but,

What, by the way, is "color space" and "color timing"?

thanks, Dave H.




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----- Original Message -----
From: JS
To: [hidden email]
Sent: Monday, December 03, 2007 1:33 PM
Subject: [SHADO] Film Stock


Sarah: "So anything shot on 35mm/16mm film has to be converted into digital
for transmission/
DVD release, but both the Digibeta and HD
are "filmed" directly onto a digital format - in other words, they
don't use film?
Why the uproar? :-)"

Aesthetics and quality.
Film in the 1960s had to be telecinied to PAL, NTSC or SECAM video
depending on where in the world it was shown, however we are fortunate
that the decision was made to shoot UFO and the other ITC series of the
period on film. If they hadn't then we would be looking at images
similar to those of Patrick Troughton era Doctor Who.

Although the quality of film and digital video have converged, they do
have aesthetic differences due to things like film's wider range of
exposure, colour space and shallower depth of field.
Of course much of this isn't consciously apparent to a general audience
on a small screen but there is an unconscious effect and HD can still
struggle at times not to look like superior home video.

Personally I find the most irritating artefact of much which is shot on
HD is........ (SKIP THE REST OF THE PARAGRAPH IF YOU DON'T ALSO WANT TO
BE IRRITATED EVERY TIME YOU SPOT IT) ... the way that often the images
look OK when everything is at rest but as soon as the camera moves (or
actors if they are large in frame), then it becomes Smear-ovision.

Torchwood is one fairly egregious example. Despite being shot on HD it
manages to look cheaper and nastier visually than the current Dr Who,
which is shot in standard-def PAL Digibeta.

Regards
John




[Non-text portions of this message have been removed]

Is this the result of the original source material then? I had put it down
to the compression for the pathetic broadcast bandwidth most HD channels
have to squeeze into. This based on the awful system standard on NTSC in
which you can see the features of an actor's face become detached from the
rest of his head (delta artefacts).

Kevin Bulmer

John wrote:-

Personally I find the most irritating artefact of much which is shot on
HD is........ (SKIP THE REST OF THE PARAGRAPH IF YOU DON'T ALSO WANT TO
BE IRRITATED EVERY TIME YOU SPOT IT) ... the way that often the images
look OK when everything is at rest but as soon as the camera moves (or
actors if they are large in frame), then it becomes Smear-ovision.


Torchwood is one fairly egregious example. Despite being shot on HD it
manages to look cheaper and nastier visually than the current Dr Who,
which is shot in standard-def PAL Digibeta.

Regards
John

Hi All,

I think this (see below) could be another artefact of compression or
display technology. The compression technology used with HD and even
conventional digital transmissions uses an algorithm that only
transmits the moving data cells of a picture.

e.g. Say we can a screen of a person standing against a
static/stationary background, initally the whole frame is transmitted,
but if the shot/scene stays the same for a number of frames, but the
person starts waving, ONLY the cells (geometric groups of pixels)
containing the moving parts (the arm waving) of the scene are
transmitted, thus cutting down the amount of data to be transmitted -
another form of compression.

If the camera then pans across, entire frames of data are then
required to be transmitted and updated to the receiving frame buffer.

Inexpensive digital receivers only contain a relatively small amount
of memory for their frame buffer, whereas more expensive systems can
buffer minutes worth of video. Sometimes the syncing between sound and
video gets way out due to this reason. The video and sound go down
different pipes as it were. There is NO sync information between sound
and video. Every now and then special transmission signals force the
two to converge, or changing channel.

If there is some data loss detected, some good systems can even
interpolate (kind of morph) the intermediate frames to some success,
whereas most current technology just shows the last full frame
received, hence the frozen picture, or worse frozen partial picture.

Also, (and sorry to be going on an on), with panning shots where huge
amounts of data are required to be updated very quickly, some
supposedly HD ready TV's just can't keep up refreshing their frame
buffers, and also some 'HD-ready' LCD refresh rates are sold actually
below the spec that is truly needed to show 'full spec' HD pictures.
Hence, in normal viewing more slowly paced films appear fine, but
fast-moving action catches out the slow refresh rates of the LCD's
themselves.

The longshot is: Final viewing quality is dependent on the quality of
the satellite receiver, the strength of signal, the size of the
received frame buffer and algoritms employed, the speed of the TV
frame/memory, and the speed/technology of the LCD refresh. There are
also many other variables, but I have gone on long enough... ...and I
typed this on my Blackberry, and my fingers have given up!

Hope this helps,

Griff

----------

Personally I find the most irritating artefact of much which is shot
on HD is........ (SKIP THE REST OF THE PARAGRAPH IF YOU DON'T ALSO
WANT TO BE IRRITATED EVERY TIME YOU SPOT IT) ... the way that often
the images look OK when everything is at rest but as soon as the
camera moves (or actors if they are large in frame), then it becomes
Smear-ovision.

Torchwood is one fairly egregious example. Despite being shot on HD it
manages to look cheaper and nastier visually than the current Dr Who,
which is shot in standard-def PAL Digibeta.

Regards
John

Thanks for the clarification Griff. I thought there might be a number of
contributing factors.

Kevin Bulmer

The problem with movement is due to a mixture of compression and HD. The
lagging with HD can be apparent on the big screen but is accentuated on
the small screen by compression. Certainly, with high compression,
standard def images can have this problem but on the same (standard def)
channels with the same compression it is always worse with HD.

I certainly think that excessive compression is the worst aspect of
digital TV and it is monumental nerve on the part of the TV channels to
try to sell us HD channels when they are not using standard def at
anything like its full quality.

Certainly in the UK if the channels delivered us uncompressed PAL
Digibeta-quality images no one would bother to buy any domestic-sized HD
set or pay extra for HD channels.

Regards
John

I've noticed that, even many many years ago on my old analog TV, sometimes I'd get an amazing clear, sharp, and consise (sp??) picture. Like I'd be watching some special or documentary, and then they'd start showing something that was filmed on some other film stock or grade of videotape and the picture quality became....WOW!!! ...for those few minutes only.....

...And then the program would continue on the standard old resolution that I was always accustomed to. I've always suspected the broadcasters/filmers were holding back on us...

Dave H.



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----- Original Message -----
From: JS
To: [hidden email]
Sent: Wednesday, December 05, 2007 9:03 AM
Subject: [SHADO] Re: Film Stock


The problem with movement is due to a mixture of compression and HD. The
lagging with HD can be apparent on the big screen but is accentuated on
the small screen by compression. Certainly, with high compression,
standard def images can have this problem but on the same (standard def)
channels with the same compression it is always worse with HD.

I certainly think that excessive compression is the worst aspect of
digital TV and it is monumental nerve on the part of the TV channels to
try to sell us HD channels when they are not using standard def at
anything like its full quality.

Certainly in the UK if the channels delivered us uncompressed PAL
Digibeta-quality images no one would bother to buy any domestic-sized HD
set or pay extra for HD channels.

Regards
John




[Non-text portions of this message have been removed]