DVD Picture Quality vs LD Picture Quality (1 Viewer)

[MikeEckman]

Recently, there was a LD PCM vs DVD Audio comparison with some great info about the differences, but I was wondering if some of you with a better grasp on the technology could explain to me why DVD has a better picture quality than LD. Before you answer though, I'll post what I think it is, and hopefully someone can elaborate.

I understand that DVD has the ability to read and playback anamorphically encoded video. I completely understand the concept of anamorphic widescreen, so for this example, lets just compare an excellent non-anamorphic DVD like The Abyss versus a Laserdisc transfer.

Secondly, I understand the PAL and NTSC standards. NTSC is 720x480 lines of resolution, and its interlaced. Since I live in North America, I'll just use NTSC for my examples.

What I dont understand is that since both LD and DVD are limited to the physical standards of NTSC and both are stored in a digital medium, shoudln't LD and DVD theoretically have the same picture capabilities?

As a matter of fact, the increased disk space and uncompressed video of LD should have allowed for BETTER picture quality?

Is the overall picture quality more of an effort thing? DVD has been a huge seller and money maker for the studios, so its in their best interests to take the original film negative, master a hi-def transfer, and then scale it back down to 480 for DVD release with high attention to detail. Whereas Laserdisc was a niche market in the 80s and 90s and the studios just threw something together.

Sorry for the long post, but I was hoping someone could elaborate on why LD looks so much "less good" than DVD.

 

[Jack Briggs]

One thing, Mike, the video signal of a LaserDisc is not stored digitally; it's analog. So there you go.

 

[MikeEckman]

How is that possible? Laserdisc is a digital platform. It is a bunch of 1s and 0s and is read by an optical laser, just like CD. How could that not be digital?

 

[Walter Kittel]

From The Laserdisc FAQ

The pulse-FM data structure on an LD (unlike ordinary VHS/Beta), is defined to hold all the information present in the composite video signal. Depending on source material and the transfer to disc, LD is above live TV broadcast quality: For NTSC, this is 425 TVL (luminance lines horizontally for 3/4 of the screen width) and about 482 scan lines, compared to 330x482 for broadcast. For PAL, the numbers are 450x560 and 400x560, respectively.

The key phrase being "pulse-FM data". LD is an analog medium and consequently there is much more correlation between playback quality and player sophistication ( and price. ) when compared to DVD.

- Walter.

 

[MikeEckman]

Post removed cause I think I got it...

 

[Damin J Toell]

As explained above, laserdiscs have pits and lands, but these do not represent 1s and 0s, they represent an FM analog waveform. See more info here. The space between the pits and the lands provides the shape of the FM waveform. This analog FM signal carries the video.

When first introduced, laserdiscs were entirely analog. Redbook PCM digital audio was added later on. The video always remained analog.

Calling laserdisc video "uncompressed" is a misnomer. It is neither compressed nor uncompressed.

DJ

 

[Damin J Toell]

That has nothing to do with digital vs. analog. A digital format can be on a magnetic medium. DAT tapes and DVHS are digital formats on magnetic media. An optical format can also be analog, as you're seeing with regard to laserdiscs. The type of medium does not determine the format of the content.

DJ

 

[MikeEckman]

Okay, I think I get it. So Laserdisc isnt like CDs....theres a difference between every pit and land on a laserdisc? I think thats what I wasnt understanding. I thought laserdisc was just another digital medium with video that was somehow not as good.

Hmmm, interesting.

 

[Vincent_P]

Laserdiscs can still look very, very good. I recently plugged my almost 15-year old Panasonic LD player into my friend's video projector for the first time and was amazed at how well some of my LDs held up being projected that large. The main issue is analog noise in the color of some titles, and composite video artifacts like "rainbox" distortion around fine lines, but nicely-produced LDs still look really nice with good detail.

Vincent

 

[Damin J Toell]

Another site, this one showing graphically how an FM analog waveform in converted to pits and lands on laserdiscs.

DJ

 

[MikeEckman]

I was watching Honey, I Shrunk the Kids last night and thought the picture quality was decent. A lot better than I remember some of my older LDs looking. Granted, I wasn't viewing them on a large projector, rather a 32" Sony WEGA-HD, but it still was respectable. And the PDM Pro-Logic track was excellent!

 

[greg_t]

There were a few anamaphoric laserdiscs created as well. But at the time there were very few 16x9 display devices unlike now, so very few lasers were made anamaphoric.

Also, Japan had a format called Muse that was anamaphoric video and was analog hi def with I think around 1025 or 1030i.

How good laserdisc looks really depends on two things, the quality of the transfer and the quality of your laserdisc player.

 

[Michael Reuben]

Emphasis added. In addition to being analog, LD stores the video signal in composite format -- i.e., with all the information blended together. DVD stores the information in component format, keeping separate and pure the various elements of the signal that LD (and VHS and broadcast) mix together. That's one of the reasons why the quality of LD playback is so dependent on the caliber of the equipment, because the first thing the equipment has to do is separate the signal into its constituents. It's a process fraught with potential to introduce artifacts, but DVD can skip it all as long you use a component connection.

M.

 

[PeterTHX]

Not exactly.

Since (at this stage) the signal is still analog, the quality of the DVD picture is dependant on the quality of the Video D/A converter (something LD didn't have).

Quality D/A video converters render a sharper picture with less MPEG2 artifacts, better & more accurate color.

One way to TRULY bypass this is to use the DVI-HDMI connection to a digital TV from a DVD player that has one.
Player quality can vary this signal to a degree as well.

 

[Michael Reuben]

Not exactly.

Some advanced LD players process the signal in the digital domain, then convert it back to analog for playback. But again, that's a different issue than the one I was addressing.

M.

 

[ChristopherDAC]

In general, DVD can have a picture quality advantage over LaserDisc owing to its increased static resolution and component encoding [neglecting, for purposes of discussion, various professional formats and the component high-definition MUSE LD, which employed a form of analog bandwidth compression; there is a thread on this, if you are interested]. Additionally, the far more extensive use of 16:9 encoding [no LD player was ever ourfitted to downscale a 16:9 picture to 4:3 letterbox, which effectively all DVD units will do] provides a practical advantage.
In some cases, the LD of a specific programme will have a higher picture quality than than the DVD release; this is usually owing to bad DVD mastering or the use of inappropriate source elements [such as a composite-video master tape]. The quality difference between the two media, however, at least at the same aspect ratio, is in general not very great; both are durable and furnish digital audio along with a high degree of time-base stability and more than half-again the horizontal resolution of even SP VHS. The great advantage of DVD over LD is not quality but form factor, and for those of us who don't begrudge the storage space LaserDisc remains a valued part of our Home Theatre arrangements.

Personally, I don't buy DVDs, simply because the shows I want to watch are on LD; in the cases where a DVD of the programme does exists, it is often inferior for one of several reasons, and more expensive to boot. Also I happen to be far more sensitive than the average person to DVD artefacts, whereas the NTSC artefacts of LD are noticable but not obnoxious, just as they were designed to be.

 

[DaViD Boulet]

The artifacts of NTSC were only "designed" to be tolerated on a 4x3 13" interlaced display viewed from more than 4 screen-widths away. I find NTSC artifacts (scan-line aliasing, dot crawl, chroma-noise, moire patterns etc) extremely distracting when viewed at "theater" proportions. What size is your display and how close do you sit? Also, what type of laserdisc player do you have?

 

[greg_t]

There's no doubt that DVD video is generally much improved over LD. I have an X9 laserdisc player and was watching my Saving private ryan laserdisc and thinking how good it looked. I then put on the DVD, and saw that the laser, even on the X9, just didn't compete. Sound of course was another story!!!

I wonder though how much closer it would be if laserdisc were still around today with anamaphoric transfers when played on something like an X9, X0, or S9? DVD would likely still get the edge, but it would be interesting to see how close it could get.

 

[Tony Kwong]

Sony did have a couple of HD downcoverted videos on squeezed 16x9 LD. Some of the best looking 480i I've seen. X0/X9 players. I havent seen a "good" version of the DVD so i cannot compare as there were very old releases.

 

[Steve_Klein]

This shouldn't be too far off-topic, and this seemed like a good place to ask...

I picked up a Pioneer LD-S9 LD player last year (brand-new in the box!) and have been using it mainly to deliver video and PCM audio to my PC's video capture and sound cards. I understand the issues behind using the composite video output vs. S-Video and since my early experiences with the format have always used (and recommended the use of) the composite output under the assumption that the display's comb filter was probably better than the player's internal circuit. Only recently had I heard that the composite output signal on later model LD players (including the LD-S9 and its brothers, the CLD-D704 and Elite CLD-99) was actually recombined after the player's internal comb filter and DSP circuit. My questions are:

1. I'm pretty familiar with the model history of Pioneer's LD player line. When (i.e. with what models) did this "faux-composite" output practice start and why was it done? It seems to make no sense, but I'll bet cost was somehow a factor...

2. For these players, does this pretty much make the S-Video output the best option regardless of the display's attributes? Granted a comparision between the two would be the best way to judge, but I'm thinking theoretically.

3. I understand that the adjustable video DSP settings only act on the S-Video output, but I've never understood what these setings really did (especially since in the past I just automatically used composite and therefore bypassed any player DSP). So in general -- and for my LD-S9 in particular -- which output and what DSP setting (I have "3D.Y/C", "3D.YNR", and "3D.CNR" -- ranging from "off" to "max") would give the truest possible representation of the original composite signal on the LD with minimal or no DSP? All settings turned down to "off"? The middle? An external resource would be fine (but I've never found one and my owner's manual is in Japanese!).

My rationale is that I'd like to capture the raw composite signal (warts and all) along with the PCM audio to AVI format, edit it, and use PC-based tools to perform any signal enhancement prior to applying lossy compression. Any and all thoughts are welcome.

Mods: If you think this belongs in a separate thread, please feel free to let me know / relocate it. The original question seemed to have been answered and this thread seems to have some eyes on it already.

Thanks!