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DVD & LaserDisc Audio

post #1 of 30
5/13/12 at 4:15pm
Thread Starter 
I've been reading the threads related to this tired question for years, but one especially caught my eye on this forum.

Even though that one is really about BRs, I found a few comparisons to be odd. I see a lot of people touting the LD's superior 'PCM' tracks as proof of quality over the DVD's lossy DD tracks.

Am I mistaken, or is it untrue that DVDs have 2CH linear PCM, just like LaserDisc? For this reason, I always thought the issue was cut & clear. If the digital 2CH PCM tracks are compared, why would there be any difference?

Am I missing something? I also see discussions venturing into different masters being used for LD, accompanied with confusing charts, then people refuting that claim, then people refuting THAT claim.

What is going on realistically? I feel like I'm missing a big and important piece of information.

Thanks all.
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post #2 of 30
5/13/12 at 4:25pm
Many DVDs have 2 channel PCM, but not all. Some LDs have two channel PCM, but many don't. (A few have AC3 and many have only analog audio.) Of those titles that do have PCM, if the two media are using exactly the same audio mix, and if they're auditioned using players with digital audio outputs, then of course the quality of the sound tracks would be identical. (Ignoring the effects of jitter which usually are inaudible, anyhow.)

Unfortunately, you'd have to examine each title individually to make sure all of the necessary prerequisites are met.
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post #3 of 30
5/13/12 at 5:12pm
Thread Starter 
I guess that's my question then.

Is there any proof that studios used different mixes for the LaserDisc and DVD versions of the same film? Why? How does VHS factor in?
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post #4 of 30
5/13/12 at 5:33pm
When laser discs were being made, the DTS 5.1 encoding was being done in-house by DTS. At various times they did different things to "remaster" the tracks for home use. These were not different mixes, but they sounded different. By the time DVD came along, the studios controlled the encoding themselves so the reissued DVDs do not necessarily sound the same as the LDs. Plus, the LDs used 1.2 Mbps DTS whereas DVDs typically used 754 kbps. For DD 5.1, LDs used 384 kbps, and DVDs typically use 448 kbps.
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post #5 of 30
5/13/12 at 5:49pm
Roger,

Thanks for the reminder about the differences in Dolby and DTS bitrates. I'd forgotten about that.

Apples,

I know of no proof either way with regard to LPCM tracks, though; i.e. I know of no list of titles which details how they were made for the two media. However, given the higher quality possible with digital DVD video compared to analog composite video as used on Laserdiscs, I would be surprised if some titles were not completely remastered for DVD, as they often are for Blu-ray. (See Roger's comments above.)

Hmm. Given their accent on quality, Criterion probably has a document somewhere detailing the work they've done on many of their titles in the different formats. A quick search just now didn't locate one, although their site reminded me that many of their production details are included with each of their titles. I don't seem to have any Criterion titles in both DVD and Laserdisc formats, though.

I'm not sure what you're getting at with your question about VHS audio.

I have no experience with D-VHS. Apparently they usually have Dolby Digital tracks, while a few have DTS audio.

Given the relatively poor video quality of some DVD titles, it seems "obvious" that they were mastered from video sources with analog VHS quality or worse. I don't know of any analog VHS tapes with digital audio tracks, but there certainly were tapes produced containing two separate analog audio tracks. Newer tapes (post 1985 or so) usually have relatively high quality stereo analog audio tracks recorded across the width of the tape in addition to the low quality "linear" tracks running the length of the tape. The linear tracks usually are monaural in order to get the best signal to noise, although some tapes have stereo.
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post #6 of 30
5/13/12 at 5:58pm
Thread Starter 
It makes sense that, in the process of releasing a film in DD or DTS, certain changes must be made (bitrate considerations, etc.), but this is irrelevant when comparing the linear PCM tracks of the two formats.

That's what I don't understand. Why were different masters supposedly used between the linear PCM tracks of respective L-discs and DVDs, and even VHS tapes?

Update: Oops, we posted at almost the exact time. I merely mentioned VHS as one of the dominant formats of the time.

The arching opinion in the thread I linked to seems to be that for each home video format, the audio tracks were (re)mastered from the original in a different way, and for some reason LD got the most faithful transcription, and DVD/VHS got the short end of the stick in that regard.
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post #7 of 30
5/13/12 at 6:13pm
Well, there certainly have been licensing issues. Before home video became popular, and even long afterward, there never was any thought given to getting permission to republish a movie in a different format. As a result, the contracts with the performers did not include any clauses allowing the studios to make them available again. Too often when republishing movies that are still covered by copyrights, it is impossible to get permission to republish some of the music, so substitutes have to be used. That requires a complete redoing of the sound track.

In other cases, of course, the people assembling a different production just figure they can do better. For example, discs generated for the European market often have quite different production values applied than those produced for the U.S. market. Many people often resort to importing discs from Europe in order to get a better quality product. Many of those differences seem to be in the video, but of course the audio tracks can be quite different when a movie is dubbed in a different language.
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post #8 of 30
5/13/12 at 6:16pm
As to LDs being better, well, that's going to vary from title to title. Like DVDs, it depends on the source materiel and the producer. VHS tapes are uniformly poorer quality, of course, just because they simply don't have the bandwidth to be otherwise. Why waste effort trying to make a silk purse out of a pig's ear?
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post #9 of 30
5/13/12 at 8:23pm
Thread Starter 
I don't think licensing issues affected some of the bigger name films that were mentioned in the thread.

I think the only way to know for sure is to ask some of the people who worked on LD/DVD production. Only they would be able to confirm or refute whether the reason for LDs perceived superior audio is different masters or something else.
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post #10 of 30
5/14/12 at 1:55pm
Thread Starter 
Wait a second, DVDs ARE NOT required to have LPCM?

This is true according to this thread, at least:

Quote:


The DVD format requires the use of EITHER a Dolby Digital or PCM soundtrack. Because DD is a compressed format that can fit a 5.1 soundtrack into one-third of the space required by a two-channel 44.1/16 PCM (CD audio) track, most DVDs use DD as the audio carrier.

It seems that the common practice with DVD production is to eschew the space-eating Linear PCM for DD/DTS, in favor of higher-quality video; at least according to my collection.

By comparison, Laserdiscs are required to have an uncompressed stereo track (analog or digital), with DD/DTS sometimes added as well.

I guess that's the difference. Laserdisc's uncompressed two channels of sound, against DVD's compressed DD.

Case closed, I think!
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post #11 of 30
5/14/12 at 2:06pm
FWIW, I have some surround-sound music DVDs (not DVD-A) which were created when DVDs were just starting to become available which have both LPCM stereo and high quality Dolby Digital 5.1 tracks. They were intentionally mastered to provide evidence that DD sound could be extremely good if proper care was taken. Their video tracks are little more than very low bitrate slide shows. I'll check this evening to see what their bitrates actually are, now that I have a (Sony BD) player which shows that info.
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post #12 of 30
5/14/12 at 2:08pm
Thread Starter 
There you go. It seems like the eventual agreed consensus was chosen to favor video over audio in DVD productions.

A shame, really.
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post #13 of 30
5/14/12 at 2:57pm
Note too that analog audio on LaserDisk is actually an FM audio system just like Beta and VHS HiFi.

So while not being a true digital system, it is close in performance CD. It does suffer from some pumping artifacts inherent in the DBX type noise reduction system they used.

The Digital PCM track is identical to redbook CD.
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post #14 of 30
5/14/12 at 3:24pm
Some DVD audio examples:
DELOS DVD Music Breakthrough (1998) Audio: DD5.0: 384Kb/s, LPCM: 48/16 1.5Mb/s; Video: 1Mb/s (fixed)
DELOS Space Spectacular (1998) Audio: DD5.0: 448Kb/s, LPCM: 48/16 1.5Mb/s; Video: 4.5Mb/s (fixed)
Tangerine Dream -- Dream Mixes (1999) Audio: LPCM: 48/16 1.5Mb/s; Video: 4 - 8Mb/sec
Disney's Fantasia (2000) Audio: DD5.0: 448Kb/sec, DTS5.0: 754Kb/s; Video: 3.8-5.6Mb/s

Edited to add:
The bitrate values are as shown by a Sony BDP-S590 Blu-ray player. The variations in video bitrates are just peaks that I happened to see with a quick look at a couple of chapters. I dunno what the averages were.
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post #15 of 30
5/14/12 at 3:48pm
Thread Starter 
Quote:
Originally Posted by Selden Ball View Post

DELOS DVD Music Breakthrough (1998) Audio: DD5.0: 384Kb/s, LPCM: 48/16 1.5Mb/s; Video: 1Mb/s (fixed)

That's pretty low.

Apparently, the story doesn't end there for DVD. A little more research into DVD audio tracks led me to discover this little bit of information:
 

Quote:


Two problems exist.

One is that most DVD players have a sort of dynamic range compression feature that compresses the signal of the front and surround channels. This is similar to a "mid-night movie mode." The exact amount of compression is unknown, it is guessed to be between 10 - 20 dB of dynamic range compression. What this means is that the differences between the quiet parts and the loud parts will not be as great as they would otherwise. Most, if not all DVD players have this "feature". Unfortunately on most DVD players it is not defeatable, I mean you can not turn it off! The Sony DVD players do allow you to disable this so called "feature."

The second problem is that all DVD players that I know of drop the LFE bass channel. This means any information in the LFE channel does not get mixed into the 2 channel downmix. Unfortunately, in action films a great deal of energy exists in the LFE channel. When DVD first came out several people claimed that their LD's had greater and deeper bass. They didn't own AC3 receivers and they were correct. When you understand that the DVD player downmix operation drops the LFE channel this observation makes sense.

Also...
 

Quote:


When Dolby Labs was asked why the audio outputs on the DVD players were crippled they said this was done because DVD is targeted at the mass market unlike the niche market LD with its very dynamic PCM mixes.

I wonder how accurate that quote is...

So not only is the soundtrack DD compressed, but dynamically compressed and missing a channel within the DVD player.

Looks like it wasn't different masters at all, but a crippled audio path.

I wonder if my Sony DVP-S7000 first-generation player drops the LFE channel as well? I know it has an option to disable the DRC in the downmixing process.


Edited by Apples555 - 11/4/12 at 9:18pm
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post #16 of 30
5/14/12 at 4:16pm
If by "missing a channel" you're referring to music being 5.0, there's nothing missing. The on-disc .1 channel is "Low Frequency Effects" for extra audio glitz for movies. Surround-sound music has 5 full-bandwidth audio channels and has no need for an LFE channel. Most movie DVDs certainly do include a .1 LFE channel, though.

I think the writer was referring to how the analog stereo output is generated from the 5.1 digital tracks within most DVD players. That's irrelevant if you're using a digital connection, as most people do these days.
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post #17 of 30
5/14/12 at 11:27pm
Quote:
Originally Posted by Selden Ball View Post

Some DVD audio examples:
DELOS DVD Music Breakthrough (1998) Audio: DD5.0: 384Kb/s, LPCM: 48/16 1.5Mb/s; Video: 1Mb/s (fixed)

Quote:
Originally Posted by Apples555 View Post

Oh damn, that's pretty low.

The original pressing of the first of the DelosDVD series, DVD Spectacular, has the 1812 Overture recorded at 640 kbps as a secret bonus track (Chapter 29 IIRC). This same feature was also provided (but not hidden) on the Pulse DVD.

Quote:


Apparently, the story doesn't end there for DVD. A little more research into DVD audio tracks led me to discover this little bit of information: I wonder how accurate that quote is...

So not only is the soundtrack DD compressed, but dynamically compressed and missing a channel within the DVD player.

WRT DRC and LFE, they are talking only about DVD players that output stereo. This has nothing to do with 5.1 decoding or bitstream outputs.
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post #18 of 30
5/15/12 at 12:08am
Thread Starter 
I think I should've made it clear that I was comparing the stereo tracks, as DD is the closest thing to that on DVDs.

I suppose it doesn't really matter.
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post #19 of 30
6/13/12 at 8:57am
I realize that this is an old thread, but I haven't visited this forum in a while. Unfortunately, there seems to be a lot of misinformation in this thread that has gone uncorrected.

Early Laserdiscs in the late '70s/early '80s had only 2-channel analog sound. CX noise reduction was added at some point along the way.

In the mid-'80s, two additional PCM digital channels were added to the format. From that point forward, almost every Laserdisc contained the movie soundtrack as 2-channel PCM, with two backup analog channels. The analog channels might contain a duplicate copy of the movie soundtrack, or supplemental content such as an audio commentary or possibly two. A very common configuration at this time was to contain the movie soundtrack on the digital channels, an audio commentary on one analog channel, and a mono downmix of the movie soundtrack on the other analog channel.

In 1995, Dolby Digital AC-3 5.1 was added. This was designed with backwards compatibility in mind. The AC-3 track was stored in RF-modulated form on one of the analog channels. All AC-3 discs also contained a 2-channel PCM version of the movie soundtrack. The extra analog channel could then be used for a mono downmix or an audio commentary. (In order to decode the DD 5.1 track, the AC-3 signal was required to be processed first by an RF-demodulator.)

Later that year, DTS 5.1 was introduced. DTS was not backwards compatible. The DTS soundtrack was stored on the dics's two digital channels. DTS discs did not include PCM sound. However, they still had the two analog channels free for a 2-channel version of the soundtrack there, or audio commentaries.

Very few DVDs have PCM sound. PCM is not mandatory on DVD. PCM is uncompressed and takes up a lot of space on a DVD. (Also, DVD only supports two channels of PCM.) You generally only see this on the occasional concert disc. The vast majority of DVDs use compressed Dolby Digital or DTS instead. 1) Because those formats take up less space on the disc, and 2) Because both DD and DTS support multi-channel 5.1. (DTS can go up to 6.1 on DVD.)

The situation gets even more complicated on Blu-ray, but I won't go into that here.
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post #20 of 30
6/13/12 at 11:35am
Josh,

Thanks for the clarifications! They do seem to correspond to my experience, although I never bought any LDs which had DTS audio.
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post #21 of 30
6/13/12 at 12:54pm
The vast majority of Laserdiscs ever released had 2-channel PCM audio. Note, however, that those PCM tracks were 16-bit/48 kHz.

Blu-ray can support multi-channel PCM (as well as lossless Dolby TrueHD or DTS-HD Master Audio) up to 24-bit/96 kHz. That's not to say that all Blu-rays are 24/96, though. Many are 16-bit and most are 48 kHz.
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post #22 of 30
6/13/12 at 6:17pm
Quote:
Originally Posted by Josh Z View Post

Very few DVDs have PCM sound. PCM is not mandatory on DVD. PCM is uncompressed and takes up a lot of space on a DVD. (Also, DVD only supports two channels of PCM.) You generally only see this on the occasional concert disc.

In the West, anyways. There's thousands of anime DVD titles with PCM 2.0 in Japan and Taiwan.
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post #23 of 30
6/13/12 at 6:43pm
Thread Starter 
Quote:
Originally Posted by Josh Z View Post

I realize that this is an old thread, but I haven't visited this forum in a while. Unfortunately, there seems to be a lot of misinformation in this thread that has gone uncorrected.
Early Laserdiscs in the late '70s/early '80s had only 2-channel analog sound. CX noise reduction was added at some point along the way.
In the mid-'80s, two additional PCM digital channels were added to the format. From that point forward, almost every Laserdisc contained the movie soundtrack as 2-channel PCM, with two backup analog channels. The analog channels might contain a duplicate copy of the movie soundtrack, or supplemental content such as an audio commentary or possibly two. A very common configuration at this time was to contain the movie soundtrack on the digital channels, an audio commentary on one analog channel, and a mono downmix of the movie soundtrack on the other analog channel.
In 1995, Dolby Digital AC-3 5.1 was added. This was designed with backwards compatibility in mind. The AC-3 track was stored in RF-modulated form on one of the analog channels. All AC-3 discs also contained a 2-channel PCM version of the movie soundtrack. The extra analog channel could then be used for a mono downmix or an audio commentary. (In order to decode the DD 5.1 track, the AC-3 signal was required to be processed first by an RF-demodulator.)
Later that year, DTS 5.1 was introduced. DTS was not backwards compatible. The DTS soundtrack was stored on the dics's two digital channels. DTS discs did not include PCM sound. However, they still had the two analog channels free for a 2-channel version of the soundtrack there, or audio commentaries.
Very few DVDs have PCM sound. PCM is not mandatory on DVD. PCM is uncompressed and takes up a lot of space on a DVD. (Also, DVD only supports two channels of PCM.) You generally only see this on the occasional concert disc. The vast majority of DVDs use compressed Dolby Digital or DTS instead. 1) Because those formats take up less space on the disc, and 2) Because both DD and DTS support multi-channel 5.1. (DTS can go up to 6.1 on DVD.)
The situation gets even more complicated on Blu-ray, but I won't go into that here.

Hey!

No problem, I'm glad to hear your input.

What you've said seems to be be in line with what I understand as well. What was the 'misinformation' you're talking about?

Since DD was added in 1995, I wonder what LD players were considered high-end then. I'm guessing Pioneer was still at the top?
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post #24 of 30
6/14/12 at 1:07pm
Quote:
Originally Posted by Apples555 View Post

Hey!
No problem, I'm glad to hear your input.
What you've said seems to be be in line with what I understand as well. What was the 'misinformation' you're talking about?

The impression given earlier in this thread was that most DVDs have PCM audio and few Laserdiscs do. It was actually the opposite.
Quote:
Since DD was added in 1995, I wonder what LD players were considered high-end then. I'm guessing Pioneer was still at the top?

Pioneer's top two American players were the CLD-D704 and the Elite CLD-99. These two players were very similar internally. The 99 had a 3D comb filter whereas the D704 only had a 2D comb filter, but that 3D model would be considered extremely primitive today. The D704 is generally considered the best "bang for your buck" LD player on the secondary market.

The CLD-D703 is the exact same player as the D704 except for the lack of an AC-3 output.

The CLD-97 was Pioneer's previous top-of-the-line model. It also lacks AC-3, but some fans prefer its video output to the 99. Personally, I think the picture from the 97 is really soft.

The truly supremo LD players were reserved for the Japanese market: the champagne-colored HLD-X9 an HLD-X0. The dual-side-playback X9 is built like a tank, and the single-side-only X0 is built like Fort Knox. In my experience, these are the only two Laserdisc players that are completely free of the "CLV white smear" artifact that plagues other LD players.
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post #25 of 30
6/22/12 at 11:59pm
Quote:
Originally Posted by Josh Z View Post

The impression given earlier in this thread was that most DVDs have PCM audio and few Laserdiscs do. It was actually the opposite.
Pioneer's top two American players were the CLD-D704 and the Elite CLD-99. These two players were very similar internally. The 99 had a 3D comb filter whereas the D704 only had a 2D comb filter, but that 3D model would be considered extremely primitive today. The D704 is generally considered the best "bang for your buck" LD player on the secondary market.
The CLD-D703 is the exact same player as the D704 except for the lack of an AC-3 output.
The CLD-97 was Pioneer's previous top-of-the-line model. It also lacks AC-3, but some fans prefer its video output to the 99. Personally, I think the picture from the 97 is really soft.
The truly supremo LD players were reserved for the Japanese market: the champagne-colored HLD-X9 an HLD-X0. The dual-side-playback X9 is built like a tank, and the single-side-only X0 is built like Fort Knox. In my experience, these are the only two Laserdisc players that are completely free of the "CLV white smear" artifact that plagues other LD players.


While I agree your statements are correct, I believe the CLD-D704 is an exact clone of Elite CLD-79.
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post #26 of 30
6/23/12 at 9:22pm
Quote:
Originally Posted by Josh Z View Post

The vast majority of Laserdiscs ever released had 2-channel PCM audio. Note, however, that those PCM tracks were 16-bit/48 kHz

Not nitpicking, but the 2 channel PCM tracks on LD is 16-bit/44,1 kHz, the same as CD.

Deck
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post #27 of 30
6/24/12 at 11:54am
Quote:
Originally Posted by EJ View Post

While I agree your statements are correct, I believe the CLD-D704 is an exact clone of Elite CLD-79.
I've also heard that the 79's audio section is slightly different.
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post #28 of 30
6/25/12 at 11:56am
Quote:
Originally Posted by EJ View Post

While I agree your statements are correct, I believe the CLD-D704 is an exact clone of Elite CLD-79.

The D704 is a D703 with an AC-3 output. There is no other difference between the two models. The CLD-79 is the "Elite" version of the D704. The video section is the same as the D704, but it has a different audio section with Legato Link, and has cosmetic differences such as the "Urushi" finish.
Edited by Josh Z - 6/26/12 at 8:02am
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post #29 of 30
6/25/12 at 2:53pm
The CLD-79 has the Audio section from the CLD-D604 but adds Legato Link processing. As stated the video section is equal to the CLD-D704.
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post #30 of 30
5/12/13 at 1:30pm
Been using an old Pioneer with the 220+ discs i just recieved. The audio and the mixes are a lot better than the same titles i have on dvd. To also step it up a notch I plug my Ld player into a BBE Sonic Max... I bet no one here has tried that or even know what the unit it. Pm me for any questions.
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