Could analogue tellys be returned as not fit for purpose?

On Tue, 22 Jan 2008 23:36:10 +0000, Marky P
wrote:

snip

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

Marky P.


Now you've done it

(cue half-pint)

On Tue, 22 Jan 2008 23:36:10 +0000, Marky P
wrote:

On Tue, 22 Jan 2008 20:32:06 -0000, "Max Demian"
wrote:

Actually analogue TVs are very useful for Laserdisc owning opera
lovers who want to read the teletext subtitles.

But I realise we are a dying breed (possibly literally).

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

The subtitles are inserted by the TV, presumably visible on a wide
screen.

All my laserdiscs are 4:3. The player's remote has a 16:9 button - not
sure what it does.

--
Max Demian

On Wed, 23 Jan 2008 16:18:02 +0000, Max Demian
wrote:

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

The subtitles are inserted by the TV, presumably visible on a wide
screen.

All my laserdiscs are 4:3. The player's remote has a 16:9 button - not
sure what it does.

It could either insert black bands down the sides of the picture, or
remove the black bands from the top & bottom - though it would have to
do the latter by duplicating lines to expand the height rather than
increasing the vertical resolution as a DVD player is able to do when
playing a 16:9 format DVD.

Laserdiscs take a fixed rate digital sample of an analogue video
signal, similar to how a WAV file is a digital sampling of an audio
signal, whereas a DVD uses a completely different method of digitally
storing the images. Thus you will not see pixelation or motion
artifacts on a laserdisc playback, but you may see aliasing artifacts.

--
Cynic

On Wed, 23 Jan 2008 16:18:02 +0000, Max Demian
wrote:

On Tue, 22 Jan 2008 23:36:10 +0000, Marky P
wrote:

On Tue, 22 Jan 2008 20:32:06 -0000, "Max Demian"
wrote:

Actually analogue TVs are very useful for Laserdisc owning opera
lovers who want to read the teletext subtitles.

But I realise we are a dying breed (possibly literally).

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

The subtitles are inserted by the TV, presumably visible on a wide
screen.

Ah, that would be closed caption then! What I had a problem with was
Star Wars laserdisc. There's a scene in the bar that had subtitles in
the black area that weren't visible on a widscreen telly.

All my laserdiscs are 4:3. The player's remote has a 16:9 button - not
sure what it does.

Mine doesn't have a 16:9 button.

Marky P.

Cynic wrote:

Laserdiscs take a fixed rate digital sample of an analogue video
signal, similar to how a WAV file is a digital sampling of an audio
signal, whereas a DVD uses a completely different method of digitally
storing the images.

I'm no expert on Laserdiscs and LD players, never having owned one, but
as far as I know, Laserdiscs store the video on the disc as _analogue_
composite video signal. So there need not be any digital sampling
involved at all in the player - although there probably might be, in
some devices. (But if there is, it's just for post-processing the signal
in fancy ways and not an inherent feature or the storage format.)

--
znark

On Thu, 24 Jan 2008 10:00:19 +0200, "Jukka Aho"
wrote:

Laserdiscs take a fixed rate digital sample of an analogue video
signal, similar to how a WAV file is a digital sampling of an audio
signal, whereas a DVD uses a completely different method of digitally
storing the images.

I'm no expert on Laserdiscs and LD players, never having owned one, but
as far as I know, Laserdiscs store the video on the disc as _analogue_
composite video signal. So there need not be any digital sampling
involved at all in the player - although there probably might be, in
some devices. (But if there is, it's just for post-processing the signal
in fancy ways and not an inherent feature or the storage format.)

Well sort of! The laserdisc uses exactly the same storage principle
as a CD or DVD, and so is only able to produce a binary level signal
at the laser read head. Instead of the binary output being organised
into bits and bytes however, each analogue sample is encoded as the
*length* of each binary "1" ("length" being both the physical length
of the pit on the disc and therefore also the length of time the
reader is outputting each "1" level). This means that there is
theoretically no granularity in the analogue output (i.e. any output
value can be encoded), but it does not eliminate the fact that the
analogue signal is sampled at intervals and therefore appears as a
stepped output rather than smoothly changing. It is very similar to
PCM (pulse code modulation).

There is obviously audio also stored on the disc, and there are
various ways that that was achieved, including the same "analogue"
principle as the video, PCM and normal digital encoding - the player
sorts out what type of disc is being played. Videodisc players can
also play normal audio CDs.

There is also two basic types of videodisc, one having a constant RPM
for playback, and the other type having a constant recording density,
so the RPM is faster for the inner tracks. The former type of disk
stored one frame per track, and so the player could do a "freeze
frame" on the former type of disk by holding the laser head over a
single track, whilst freeze-frame was not possible on the latter type
of disk because the player had no means of storing a frame. The
playing time for constant RPM discs was however quite short - IIRC
about 30 minutes per side.

Laserdiscs are also double-sided, and many players required you to
turn over the disc to play the second half of a movie (and some movies
took more than one disc). The player I once owned could play both
sides of the disc without manually changing it - though the movie
would pause for an appreciable time whilst the laser picked up the
second side and the direction of rotation of the disc was reversed.
Laser discs are about the same size as an LP record (about 12 inches
diameter), they are quite heavy and not at all flexible.

--
Cynic

On Wed, 23 Jan 2008 20:19:10 +0000, Marky P
wrote:

On Wed, 23 Jan 2008 16:18:02 +0000, Max Demian
wrote:

On Tue, 22 Jan 2008 23:36:10 +0000, Marky P
wrote:

On Tue, 22 Jan 2008 20:32:06 -0000, "Max Demian"
wrote:

Actually analogue TVs are very useful for Laserdisc owning opera
lovers who want to read the teletext subtitles.

But I realise we are a dying breed (possibly literally).

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

The subtitles are inserted by the TV, presumably visible on a wide
screen.

Ah, that would be closed caption then!

Yes, they are just the same as the 888 type subtitles for the deaf,
except they are 168 for English, and other numbers for the other
languages on some discs.

There is also a 100 page, and others advertising other laserdiscs.

What I had a problem with was
Star Wars laserdisc. There's a scene in the bar that had subtitles in
the black area that weren't visible on a widscreen telly.

Was that a widescreen film?

What would it do with a 4:3 TV?

--
Max Demian

On Thu, 24 Jan 2008 14:30:43 +0000, Max Demian
wrote:

On Wed, 23 Jan 2008 20:19:10 +0000, Marky P
wrote:

On Wed, 23 Jan 2008 16:18:02 +0000, Max Demian
wrote:

On Tue, 22 Jan 2008 23:36:10 +0000, Marky P
wrote:

On Tue, 22 Jan 2008 20:32:06 -0000, "Max Demian"
wrote:

Actually analogue TVs are very useful for Laserdisc owning opera
lovers who want to read the teletext subtitles.

But I realise we are a dying breed (possibly literally).

Laserdisc players were designed to be used with 4:3 tellys, even
though they mostly contained widescreen films, so when viewing 'zoomed
in' on a widescreen telly, you would lose any subtitles.

The subtitles are inserted by the TV, presumably visible on a wide
screen.

Ah, that would be closed caption then!

Yes, they are just the same as the 888 type subtitles for the deaf,
except they are 168 for English, and other numbers for the other
languages on some discs.

There is also a 100 page, and others advertising other laserdiscs.

What I had a problem with was
Star Wars laserdisc. There's a scene in the bar that had subtitles in
the black area that weren't visible on a widscreen telly.

Was that a widescreen film?

Yes

What would it do with a 4:3 TV?

Have wide black bars with the subtitles visible in the bottom bar.

Marky P.

On Thu, 24 Jan 2008 12:59:40 +0000, Cynic
wrote:

On Thu, 24 Jan 2008 10:00:19 +0200, "Jukka Aho"
wrote:



There is also two basic types of videodisc, one having a constant RPM
for playback, and the other type having a constant recording density,
so the RPM is faster for the inner tracks. The former type of disk
stored one frame per track, and so the player could do a "freeze
frame" on the former type of disk by holding the laser head over a
single track, whilst freeze-frame was not possible on the latter type
of disk because the player had no means of storing a frame. The
playing time for constant RPM discs was however quite short - IIRC
about 30 minutes per side.

pedant mode on

To use the correct phrases, constant RPM were CAV (constant angular
velocity) and the 'long play' ones were CLV (constant linear velocity)

pedant mode off

My Pioneer LD player could also freeze frame CLV discs by storing a
still frame in it's memory.

Marky P.

On Thu, 24 Jan 2008 23:27:09 +0000, Marky P
wrote:

There is also two basic types of videodisc, one having a constant RPM
for playback, and the other type having a constant recording density,
so the RPM is faster for the inner tracks. The former type of disk
stored one frame per track, and so the player could do a "freeze
frame" on the former type of disk by holding the laser head over a
single track, whilst freeze-frame was not possible on the latter type
of disk because the player had no means of storing a frame. The
playing time for constant RPM discs was however quite short - IIRC
about 30 minutes per side.

pedant mode on

To use the correct phrases, constant RPM were CAV (constant angular
velocity) and the 'long play' ones were CLV (constant linear velocity)

pedant mode off

My Pioneer LD player could also freeze frame CLV discs by storing a
still frame in it's memory.

In which case it was almost certainly first converting the input into
conventional digital form rather than displaying the semi-analogue
data straight off the disc. IOW a bolt-on post-processing feature
rather than something inherent in the technology. I once owned a TV
set that could do freeze-frame - and it could also display 4 different
TV channels at the same time or display a second channel as a small
picture in the corner of the channel being viewed, and a number of
other clever but rather pointless tricks that I never used.

My laserdisc player had a huge heap of features that were so complex
to use that you'd need to sit with the manual if you every found the
need to use them - and some features that I never got round to
understanding what they actually achieved! You could, for example,
enter a number of "bookmarks" based upon disc relative or chapter
relative time or frames, then instruct the player to play back each
section you had bookmarked in a specified order. I have no idea what
possible reason a person might have for wanting to do such a thing!

--
Cynic