Saturday, April 14, 2012

Dirty Little Secrets- "Surround Sound" formats on LVD , DVD, & BluRay

Generally speaking - the LPCM tracks on a CD sound better than a MP3 recording of that same source material.. Now - the Original Final Master Tape/Disc recording has more to do with the way something sounds overall more than the recording format, I know that. However the higher bit rate produced by the CD Red Book standard of 1411kbps for 2Ch stereo does help produces better dynamic's. So how do the compressed sound formats on DVD compare? Well -here's the thing about AC3RF. The bit rate on Laserdiscs is recorded at 384 kbps, 5.1 Ch. or in other words (pun intended) a mere 64kbps per channel, which is sadly enough about ='s the lower 2CH MP3 128 kbps rate, which just so happens to be the "streaming" bit rate utilized by many music server's, for copyright law purposes.    
       Now, it's generally known that in order to get "good" sound playback from MP3, don't download or record in ANY bit rate less than 256 kbps.(My person 2cents on this subject here after many blind A/B listening test is that vocals hold up well, but I can still here difference in some things between the LPCM version and MP3, like the hi hats, and other cymbals used in a typical drum kit, for example) MP3' streams at the bit rate of 64kbps very often have a "metal" echo like sound , like many stations (channel numbers) on the Digital Sirius XM Sat/Internet Radio network.

Ok, with all that in mind, add to that fact that Dolby Digital 5.1 just doesn't have the same dynamic range as LPCM and to make matter's even worse (hold on to your hats1) DDAC3 on many DVD soundtracks is not always 5.1. (the case with many movies produced before 1991 that have not been "remastered") and many disc do not advertize this little Dirty Fact. Some do, but in many cases, it's kept a secret.
 
CRYSTAL chip used for most surround EX receivers before HD.
          A DD track can be, and is often only 2.0 or 2.1 , 3, 4, 4.1, 5.0 or even worse, I have the Original (late 70's) Battlestar Galactica Movie in which the soundtrack was only produced in......that's right...MONO. So this disc is only DD 1.1 ! and therefore, only the Center, and LFE CH's "light" on my surround receiver's optical Ch Indicator display. So, what about the bit rates of these disc? Is the total bit rate (up to 440kbps on DVD) utilized for those disc that contain less than 5.1 ch.'s in order to help maintain fidelity? since they are "missing" Channels worth of info.? Many times that's not the case. The BSG disc is only recorded at 128kbps (64kbps per Ch). If your 2.0 DD AC3 (128kbps) encoded disc is put through your surround's Pro-logic II processor, then you have only 128kbps "worth" of digital info for all 5.1 Ch.'s. You do the math. That's why (my 2cents here) DDAC3 often "sounds" worse than the LD's Digital  LPCM soundtrack,  ( even though that track is only 2-ch, and not 5.1 ) and by far, in my opinion, worse than the DTS track (750kbps DVD, 1500kbps LD) soundtracks. The DTS track LaserDisc are nothing short of amazing !

With the BluRay Disc, the HD soundtracks, on most titles are being presented, or so it sure seems,( regardless of the fact that they can deliver constant ,not variable, bit rates up to 6.0 Mbit/s) at the 1500kbps "core" rate for DTS, (which still sounds Great!) in order to maintain / and remain "BACKWARD COMPATIBLE" (compliance for more widespread acceptance) with older gear that does not have HDMI connections or HD surround decoding, since the older Crystal chips can handle this data bitrate through the optical input.

          BOTH DDTHD & DTS-HD require an HDMI cord to send those higher multi channel bitrates to an HD capable surround decoding receiver because the standard coax or optical digital out not only won't do it (this may be to stop anyone from making a direct digital copies of the HD 7.1 surround track) but, my older 2002 surround receiver's DD/DTS chipset, can only process a maxium of 1.5Mbps anyway. If "they" sent a 5 or 7 ch HD track "out" to my surround processor from the Blu-ray player, with a higher data rate that is currently only supported by HDMI) the surround processor on board an non HD surround receiver would not be capable of processing it. Now, both TrueHD and DTS-HD use lossless data compression to save space on the disc. The LPCM is fed into the encoder and compressed to save space.

         "They" realize that most customers will never know the difference, or could tell the difference, or own the level of equipment that is needed to tell/hear these differences anyway, and or, are just to stupid to even bother taking the time to research these details, which I believe has been more than proven by the number of El-cheapo piece of crap "Home Theater in the Box" and "Soundbars" (with 5.1 "down converters built in" to them) that are for sale out there(or have sold) already. The only way I could listen to the 6 track LPCM surround MasterTrack (the exact copy of the studio Master)or the Dolby or DTS HD track was because my HDDVD player had 6 ch. analog outputs, and my receiver had 6 ch analog inputs for "SACD/DVD-A" players. I will say the HD tracks hold up well very well when compared to the LPCM Master, and that's because on playback, the lossless codecs use whatever bandwidth they need at any given moment. 


             PCM bitrates are fixed, even when there's very little sound being played. I will say this. The "sound" of the "rain" on the 7.1 LPCM track of "The Crimson Tide" on Blu-ray was more "spot on" than any other "rain" track I've had the pleasure of listening to. While the Standard DD track did a damn good job considering the compression that was being used, nothing, and mean nothing, comes as close to the real life sound of rain than this. WOW!

Thursday, April 5, 2012

How much data ( converted to Digital ) was stored on a Laserdisc?

Here is a question just asked recently over on a Facebook Fan Page. I've seen this question  ( or subject matter)  several dozen times before though out the years, and have often wondered the same thing myself.  
Truth be told -
 I've attempted several times before to answer this question in a dozen or so different comments, but I was afraid my responses would just get buried (and it did ) and therefore no one would ever read it.  Discovering the answer to the question  required tons of research, because the answer wasn't so clean cut.  While I don't claim to be an expert on the subject, what follows is THE BEST possible answer I've been able to piece together from many different sources.
 I've  added my personal two cents at the end of this read.   For all those fans over on Laserdisc Forever, LD Vault, and LDDB, this one is for you then. 
T2: LaserDisc, DVD & Blu-ray

From the top, we know:
The picture signal that the Laservision disc (LVD), or Laserdisc (LD) carries is actually analog in format. that's right - ANALOG. Just like vhs. More really- more like S-VHS. ( Right now- some Hi8 or Beta lover is screaming! )  Therefore, it's really can't be measured in MB's or GB's, because those are really only Digital storage measurements, but we will get to that shortly. 
Only the LPCM audio tracks are digital, and those can be/ and are measured in MB's, at the Redbook standard at 1411kbps. Later, DTS disc were encoded at 1440kbps for all 5.1Tracks.

Now- standard pre recorded CD's are  74mins long ( yes- most CD-R disc can now store up to 80mins of music in this format- but many player's have issues w/ burnt data at the extremities edge of the disc ) and hold 700MB, then that’s just a bit ( pun intended )  shy of 1MB per min, so rounding up, a CLV disc could hold an hour of LPCM sound per side, so that could be said to =  just shy of 600MB's per side for sound. Yes? OK? 

OK. Now we will deal with the analog encoded video portion of the disc. How do we compare a system that stored the analog video on a surface covered with oval pits (CLV had 30 Billion pits, the spiral from the center out is get this - 24 miles long ! & the laser reads this information at something like 424 inches per sec) in order to reproduce the stored video picture with that of a digital storage medium? Well that's the real trick.

LVD, or LD and DVD (Stamped) are vastly different.
 LD pit size is 1.6um and the gap space between them ( the pits) was huge, something like 1.3um's. DVD, on the other hand, uses a 650 nm wavelength laser diode light as opposed to a 780 nm for LD. This permits a smaller pit to be etched on the media surface compared to CDs (0.74 ┬Ám), allowing in part for DVD's increased storage capacity. The gap spacing is also less.

In comparison, Blu-ray Disc, uses a wavelength of 405 nm, and one dual-layer disc has a 50 GB storage capacity. As far as the gap is concerned,  look at like an older 50in 720 Plasma display TV, ( or- - if you happen to still have one of those micro LCD / DLP 720p projection sets)  and compare it side by side to a 1080p newer 4K UHD set.  In the same amount space, the 1080p set has Twice the amount of pixels than that of the 720p, (1920 X 1080, compared to 1280 X 760.  Or, in other words, 2.2 megapixels, verse a megapixel) all because of gap spacing. You will see that the gaps between the pixels on the 720 display are far larger than the 1080. So,  what this means is that a  "pixel" can be different sizes, depending on the size and resolution of your TV screen - or the throw from your LCD/DLP front projector to the wall - which will effect the size of both the picture and pixel you see projected.
  The new Ipad  now has 3 times the amount of pixels in it screen than a 1080p HDTv! So, I guess what I'm trying to say is - that a pit, is not always "a pit" because the sizes and gaps in the pits of the different storage formats are different. Get it ?...........................

Anyways, that is why Laserdisc are so large !
 Now, If they were to go back and use the same size disc with a 405nm laser that’s used for Blu-ray, and modern day encoding systems, then everything simply becomes a simple matter of surface area. Of course, the Blu-ray disc has the double layer capability that LD never had, and the pits are ever so much smaller, and the gap spacing is almost non-existent by comparison.
But since the LD is 2.5 larger than a Blu-ray disc, IF they were to STAMP an HD LVD today, I'd say she could store about 130GB a side or 260GB total- but that’s just my best guess, of course. 

MOVING ON -
This was copied and pasted  from an AVS form written by "DOS Guy” years ago, dealing w/ the subject of comparing  LD's storage VS a compact-disc- in which he stated: 
"So, if the information encoded onto a laserdisc represented digital data (0s and 1s), how much data would it hold?  A LD is 30 cm, so roughly 10.6 cm is the central hub. Let's also assume that the outermost 2 mm aren't recorded on.  The radius of a LD becomes 14.8 cm, so Pi x 14.8^2 = 688.13 cm2, minus the central hub radius of 5.3 cm, Pi x 5.3^2 = 88.25 cm2, for a total recordable surface area of about 599.89 cm2. If we assume that the LD used the same laser (as a CD) to read tracks of the same width, then the LD also has an areal density of 7.298 MB/cm2, giving a laserdisc about 4.276 GB a side, or 8.551 GB total, back and front."

 "Although you can't compare analog and digital, 
the result is nevertheless interesting. A laserdisc requires the equivalent of 4.3 GB of digital data to encode 60 minutes of information, whereas a DVD encodes 120 minutes of video in 4.7 GB, and that video yields a higher resolution (720x480 for DVD, vs. 560x480 for LVD) thanks to a finer laser and MPEG-2 compression, which is made possible by “digital data” instead of analog data." 

So the storage cap is about the same, the video just takes up that much more room. So, if we subtract the 576MB for digital audio tracks, we are left with 3.7 GB’s. How much of that space is used for the 2 analog sound channels? Well, we know that a Dolby AC-3 5.1 384kbps track will fit into one, so multiply that by 2, and that’s 768kbps (like adding the equivalent of a standard DVD DTS Track) or, just a little less than half of the LPCM tracks, at 276MB. So 3.7 GB -.276GB for CX analog tracks and we are left with: 
3.4 GB for an hour of Video!

That same 411 can easily fit into a much smaller space today. (2.2GB for Video) Take that same information (560x480) w/ 420 scan lines, and convert it to DVD, like, for instance, the very latest Re-release ( not the original )  6 -disc Box Set of Season One of the X-files, which I STRONGLY believe to be nothing more than a Laserdisc Dub! 

 I have the Pilot episode on LD, and A/B ing the two   ( I plugged my LD-V8000 Laserdisc player into the Tosh DVD recorder's input, and did nothing more that switch from the pre-recorded store bought DVD ( which was playing in the recorder) to "Input One" source on the Tosh, so we were not viewing a Laserdisc transfer, but the Laserdisc itself through the recorder- which has built in HDMI output to my Panasonic 26in 720p HD LCD.)  I could see no difference between them at all, in terms of resolution -much like most of original 1st release of Star Trek: The Next Generation on DVD. ( Which I also believe to be sourced from the Laserdisc release)  Even though both these series were shot on Kodak 35mm film, those elements were transferred to D-1 /2 Digital video tape    ( for both editing, cost, and special effects reasons @ the time) and those limitation show on these releases. 

The only way I knew I was watching the DVD version & NOT the LD source was that the Laserdisc ( by nature of the format) are brighter than their DVD counterparts, and the Black level on the Laser was nowhere near as dark as the DVD.  Thanks to finer laser, smaller pits, less gap, MPEG 2 COMPRESION, & the Dual Layer format (w/ 9.4GB’s of storage), "they " managed to transfer four - 50 minute long episodes of The X-files , or 2 full Laserdiscs - both sides (on LVD, each 50 min episode resides on one single side of a disc) onto one Single DVD. Keep in mind, that in order to do this, the LPCM audio track is converted and reduced to a mere Mp3 quality 2.0 Dolby Digital Stereo track. Still, there you have it. 

Original X-file LaserVideoDisc Back-cover.


Oh, one last thought.
 Know who you can thank for "Digital Copy", the "feature that's not a feature?" Steve Jobs? Nope. Sony. Yep, good old Sony. See "they" developed this compression format known as H.264MPEG4, the very one used for, yep, you guessed it - Blu-ray. However, back in the day (2004) before a High Cap disc came along, "they" wanted to make movies "portable", and presto , the UMD , the little mini Digital Media Disc, based upon the MD, was created, for the PSP, with a storage space of 1.8 GB, and ATRAAC3 plus encoded (bad, very bad) 128kps 2 ch sound. Sound familiar? Sound a little like the same spec sheet as your Digital Copy?
 That's because, for the most part, it is:


 The format almost took off, but Sony limited it's playback capabilities to the PSP, and I guess people really don't want to own disc that small. Maybe the kids lose them? I don't know? Like Laserdisc, production of the UMD has come to an end. Unlike Laserdisc, people don't seem to be collecting these things. Heck, the newer PSP's stream video over WI-FI at the same data rate.

 Although "Digital Copy" (1.6 GB's MAX of video data)(that's right, a memory card or USB stick holds way more today) benefits from being "transferred and mastered from" an Hi Def source",
 which (besides being viewed on a smaller screen then our big screen TV's) is why the picture holds up.          
The 32GB version of This Class10 SD card: $10bucks.
This one stores more data than One Standard BRD,
or- nearly 14 DVD's. OH-it' data tranfer rate is also faster.
It's could hold 40 of your "Digital Copy" movies.
   

 Of course-
 "Digital Copy" is really just another way for the studio's to "attempt to"
 control their product.
Only StarTrek TNG film not on LD

Which is another story, altogether.
             END
For more info on Digital copy: 
read this:  http://www.sonypictures.com/residentevil/bonuscopy/faq.html
 



 


                                        

Wednesday, April 4, 2012

How to build an Inexpensive Isolation Platform: (IIP)

Pic of the parts you will need
Time to go shopping! List of supplies below.
cost more than the glue

Stone Paint
                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
                                                                 
          One audio/ video geek’s hobby project journeys 
              into the art of construction,
                   without constructing art.

Question? 
Have you ever checked out just how damned 
expensive some of these Isolation Platforms are?

I personally think the going prices are crazy. 
Now, granted, if I had a couple of grand invested 
in some insanely high end  turntable, 
like those young fellows at Acoustic Sounds,
 ( I don't. My Technics turntable is over 30 years old, 
and runs perfectly,)  well maybe I would consider
 spending several hundred dollars on the best damn 
Isolation Platform that I could possibly afford
 One wooden platform filled with fiberglass 
    currently sells on the web for over $2,000! 
Now - that's my definition of INSANE !

I’m sure I’m not the only A/V geek out there
 that’s ever wanted his (or her ) very own isolation platform, without having to spend a “mint.”
Although, to be honest, I’ve never, in all my years, 
personally known a female A/V geek. 
( Why- yes, that Is Sad - I know. )
 BTW, a  “mint” to me, I say would be,
   several hundred dollars.
 OK, so Why that amount?
Well , because, quite frankly, the cost of my gear 
just doesn’t warrant it.  Also, as  father of two, 
I just can’t justify it.
So I decided to look into the cost of building my own,
 without breaking the bank. 
 IF you only knew what I pay in child support...
This Isolation Platform doesn't have or need 
to be perfect, it simply has to do “the job”.
 ( Who am I kidding?)
  I’m not building one with the idea/ or goal of 
  attempting to improve the sonic characteristics
 of a stupid high -end turntable.
 No, I simple want to isolate an old Laserdisc player,
 a CD player, a DVD recorder and tape deck.  
 1st I looked at the cost of marble, 
which I  discovered started
  at  $39 a SQuare foot, and went up! 
Even though Marble is what I really, really wanted, 
that would have blown the whole budget. 
Oh, the budget. The budget you say. 
What just was my budget?
 Just how cheaply am I attempting to make this thing, and still have it do the job? Well, let’s just say, 
 for the sake of argument, 
that $49 dollars was the budget. 
Oh, and by the way, $49 was not the budget 
for just a mere single Isolation Platform, but rather,
 that was the budget for two of them. 
That’s right - two of them!
So I'm attempting to build A $25 Isolation Platform !
What's that? Can’t be done you say?
Let me quote old Buzz Light-year here.   “CAN!”
How?
Well, let’s start with our "Home Depot" Shopping list, 
shall we? I simply can’t afford marble. However, 
I can afford some leftover ceramic / porcelain 
Floor Tiles. 
They aren't thick enough (yet) to do the job, 
but we can and will, address / fix this. 
So - here we go.

1)    18 X 18 Floor tile. Times Four.(open stock)     $8
2)    8 3-1/2” Round Felt Sliders (feet)  Two-packs  $11
3)    Non-sanded grout gray caulk  (Expensive!)       $7
4)    Heavy Duty PL 375 (glue)                                $2
5)    Industrial gray spray primer                               $6
6)    2 cans of Sandstone Spray paint (on clearance) $9
7)    3M Masking Tape                                             $3
8)    Tax:         $ 2.53
9)    Total =    $48.53 !!!! 
10)    Optional feet (HD Rack balls and wood cup holders)$3.25&$5 = $8.25

     OK, w/ the optional feet, we went over budget, 
& it turns out, you only really need 1 can of paint.
I just blended the two colors. 
But I hope you see why I assembled 2 Platforms. 
The cost to build the second platform only really
 added $9.50 in real world dollars,
 ( $4 dollars for the tile, plus $5.50 for the "feet")
 because the rest of the cost to build the 1st platform
 was fixed, at $39, & would have left me stuck
 w/ "leftover" material. Now, there was little waste,
 but better distribution of cost.
 Could I have built a third with these material
        for another $9.50? No. No cause
 the 3rd one would have added almost 
                    $20 in additional material.
Anyhow,
 here is the 411 on how to construct the platform.
It’s rather simple. (see pics below)

1)    Cut the tip off the HD PL 375 (glue) and 
            lay it into the middle of tile.
     WARNING! This stuff dries VERY quickly. 
          I mean, like in under 2 mins!

2)    Press tile together firmly, making sure they line up. 
        Let sit for 20 minutes.

3)    Take non-sanded grout and lay into 
       the exposed seam on all 4 sides, filling it. Let it dry.
        (FYI, I let this stand overnight)

4)    Mask off the edges

5)    Spray edges with Gray primer.

6)    Let dry. (see instructions on the Can)

7)    Lightly sand if you wish.

8)    Paint. (Warning! Do NOT Paint the bottom.)

9)    Let Paint dry. (4 hours) Then remove masking tape.

10)  Add HD PL 375 glue at the center of the black tops 
            of the felt pads,  & glue them to the bottom 
                           of  platform, & let dry.

And that’s it. 
I present to you,  your very own 
$25 Inexpensive Isolation Platform, or IIP, for short.
CONGRATS!

So, what do you think of my solution?      


protect "underside"
non-sanded grout caulk

Stone painted

add felt feet