Is There a Move Towards Pseudo Random Scanning for Digital TV Displays?

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Discussion Overview

The discussion revolves around the potential for implementing pseudo random scanning techniques in digital TV displays as an alternative to traditional raster scanning. Participants explore the implications for video quality, artifacts, and resolution, while also considering the technical feasibility and existing standards.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants question whether there has been any movement towards pseudo random scanning in digital displays, suggesting that traditional raster scanning is still the norm.
  • One participant argues that the encoding of video data and the use of frame stores could allow for alternatives to raster scanning, indicating that memory is now affordable enough for such implementations.
  • Another participant expresses interest in building a device to manipulate video signals, particularly to attenuate commercials, raising questions about the feasibility of such a device within existing legal frameworks.
  • Some participants reflect on historical scanning methods, such as PAL and NTSC, and speculate on how MPEG technology could benefit from new display methods.
  • There are mentions of existing standards, such as the A53 standard, and links to resources, although some participants express skepticism about their relevance to the current discussion.
  • Technical details about the limitations of current digital signal processing and the persistence of raster-based outputs in modern technology are also discussed.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the viability or implementation of pseudo random scanning in digital displays. Multiple competing views and uncertainties remain regarding the technical aspects and potential benefits.

Contextual Notes

Participants note limitations in their understanding of current technologies and standards, as well as the rapid evolution of the field, which may affect the applicability of their ideas.

Who May Find This Useful

Individuals interested in digital display technology, video processing, and the implications of scanning methods on image quality may find this discussion relevant.

sophiecentaur
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Since the transition from CRT to digital displays, has there been any move to modify the displays to pseudo random scan for TV pictures, as opposed to raster scan? I have tried Google but the only references I can find refer to vector graphics, which is not what I wanted.
There must be someone around who just 'knows' the answer to this one.
I can't imagine that the original digital displays were not raster scan but memory is cheap now and an alternative to a conventional line-by-line raster could be much better for artifacts and resolution. Will this be the next selling feature, once everyone has 3D?
 
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This depends on video cable. How they encode the video data. Still this will have some serial manner and raster scan is only the way.
 
Kholdstare said:
This depends on video cable. How they encode the video data. Still this will have some serial manner and raster scan is only the way.

It doesn't depend on the data link at all. Serial to parallel conversion is done all the time. All you need is a frame store (a very few £). It's done in the original digital coding of the signal and we could now afford it at consumer level. The MPEG decoder uses a pretty hefty amount of memory, in any case and the picture information isn't truly "serial", but in 16X16 pxl blocks.
I Am looking for information from someone who actually 'knows' about this.
 
I guess you've seen the A53 standards here? Probably no help.

My interest would be in building a device to interpose in the , say, S-video line and recognize the content identifiers. Content identified as commercials would have the volume lowered ~40db and the brightness turned down to near dark.
In US there's laws against blocking ads but so far as i know you can attenuate them.

Might it work, do you think ?
 
jim hardy said:
I guess you've seen the A53 standards here? Probably no help.

My interest would be in building a device to interpose in the , say, S-video line and recognize the content identifiers. Content identified as commercials would have the volume lowered ~40db and the brightness turned down to near dark.
In US there's laws against blocking ads but so far as i know you can attenuate them.

Might it work, do you think ?
Jim
I grew up on PAL, which is based on 625 line interlaced scanning. It just can't be optimal for a display which could do anything you wanted. I just wondered about how MPEG could benefit from an alternative way of displaying moving pictures on a pixcel (?) sequential basis.

Do any displays utilise this?
 
Jim
I grew up on PAL, which is based on 625 line interlaced scanning. It just can't be optimal for a display which could do anything you wanted. I just wondered about how MPEG could benefit from an alternative way of displaying moving pictures on a pixcel (?) sequential basis.

Do any displays utilise this?

Sophie I'm still NTSC 545 lines.
My brief excursion into video was in days of the TI-99. I fount its internal board drilled for an alternate RGB video processor IC and bought a couple . But the field was changing so fast i decided not to get into it.
So I'm sure not fluent anymore.

From what I've seen in TI DSP offerings i cannot imagine they aren't. Will see if i can find a tutorial suitable for us, er, engineers in transition...

old jim
 
jim hardy said:
I guess you've seen the A53 standards here? Probably no help.

My interest would be in building a device to interpose in the , say, S-video line and recognize the content identifiers. Content identified as commercials would have the volume lowered ~40db and the brightness turned down to near dark.
In US there's laws against blocking ads but so far as i know you can attenuate them.

Might it work, do you think ?

Take a look at the code in MYTHTV commercial skip functions.

http://www.mythtv.org/ http://www.mythtv.org/wiki/Commercial_Detection
 
Thanks nsa haven't found the code yet but will persevere.

Sophie - i forgot to post the link for those standards.

http://www.atsc.org/cms/index.php/standards/published-standards/50-atsc-a53-standard

more here
http://www.atsc.org/cms/index.php/standards/published-standards?layout=default
 
Last edited by a moderator:
Sophie i spoke too soon.

All the TI stuff i can find appears to output raster based analog, despite its considerable computing power.
If i understand correctly, TV is still 30 frames/sec but with the fast computer DSP chips they can generate intermediate frames to smooth motion and compensate for response time of whatever device makes individual pixels. Hence 120 and 240 hz TV's.

http://www.ti.com/product/ths8200-ep
http://www.ti.com/product/tms320dm6446their OMAP line for mobile devices seems to be pushing the frontier.

Just out of my field. Sorry to waste your time. But I've been curious too.
 

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