Usergroups  ·  Register ·    Profile  ·  Log in to check your private messages  ·   Log in     

DVD for Dummies 101



DVD for Dummies 101
Author
Message
Miyuki
Minawa Andou


Joined: 29 Jul 2003
Posts: 590
Location: Melbourne

PostPosted: Tue Aug 05, 2003 10:28 pm    Post subject: DVD for Dummies 101 Reply with quote
Hi there ^^;;

I hope I don't annoy the mods but I guess this is the logical place to put my topic I hope ^^;;; *hides from the mods*

I was just wondering when I'm reading DVD reviews or when you guys mention things like quality and stuff what exactly do I look for in a quality DVD transfer? Because sometimes when I see a DVD review saying that it was a bad transfer or there's little things here and there that are bad, I seem to be blind to these imperfections because I can't seem to see them ^^;; So I thought I might pose some Questions here, I see particularly how people have said how bad Siren's transfers are but...I have no problems with Now and Then, Here and there...so I thought I might pose some Q's to you DVD aficionados ^^

What makes a quality transfer?
How long does it usually take to transfer a movie to DVD?
What are the "DVD Masters"?
What on earth is the difference between NTSC and PAL?
What's aliasing or MPEG artifacts and other glitches with DVD?
What's 16:9 anamorphic mean?
What's the difference b/w 5.1 and 2.0 and all that surround sound stuff?

I'm sure I had more but these are all I can think of now...Answer them if you can and thank you for your time!

Arigatou gozaimasu! *bows*
_________________
Held in young hands, that light is shivering.
I've wandered all this way,
Not even knowing your name.
Wandering to the edge of time.
Back to top
View user's profile Send private message
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Tue Aug 05, 2003 11:38 pm    Post subject: Re: DVD for Dummies 101 Reply with quote
Miyuki wrote:
I was just wondering when I'm reading DVD reviews or when you guys mention things like quality and stuff what exactly do I look for in a quality DVD transfer?


The simple answer to this question is, a perfect DVD is one that looks and sounds exactly as the movie (OVA, TV series) did the day it was made.

The first thing to realise is that a movie will not fit onto the amount of space a DVD holds -- the size of the files is too big. To put it on DVD they have to reduce the size by using a process called MPEG compression (for the video) and Dolby Digital compression (for the sound). There is a lot of clever mathematics behind it all, but in essence a lot of what is done to make it smaller is making the picture or sound worse, but in ways your eyes or ears can't detect.

At least that's the theory. Getting that right is quite an art form, and if it's done wrong then you can see or hear the differences.

There are also other technical faults due to not having good enough copies of the original to make the DVD from. This site has some information on video artifacts.

Quote:
I seem to be blind to these imperfections because I can't seem to see them ^^;;


That's not necessarily a bad thing, though it can be a factor of the equipment you're using to view DVDs. The bigger your screen, for example, the more likely you are to see video problems. People with projectors are driven insane by bad DVDs.

Quote:
How long does it usually take to transfer a movie to DVD?


That's a simple question that has a very complicated answer. There are a lot of things that go into making a DVD. Some of these things include:


  • turning the original film or TV station format video into a digital video file (called "scanning" or sometimes "telecine")
  • turning the original sounds into a digital sound file (these two can be done together)
  • compressing the sound and video files
  • translating the script and making subtitles
  • designing menus and cover and disc artwork
  • assembling all the DVD content onto a DVD


Some of these steps might have to be done multiple times if it turns out something went wrong, or the quality wasn't good enough. It can take a long time.

Quote:
What are the "DVD Masters"?


This is whatever media/format the DVD makers received their copies of the show on. You want the best quality format you can get, as your DVD can never be better than that.

Quote:
What on earth is the difference between NTSC and PAL?


PAL is the television standard for Australia, as well as most of Europe. NTSC is the television standard for Japan and North America.

In practical terms, PAL shows more details and NTSC is less flickery.

Quote:
What's aliasing or MPEG artifacts and other glitches with DVD?


The link I gave earlier to michaeldvd.com.au will answer these questions, if you have enough patience to want to learn. That site also has a bunch more articles (see the bottom "General Articles" section). There's also the DVD FAQ, which is very good.

Quote:
What's 16:9 anamorphic mean?


See this article. Or the FAQ, which also has an explanation, I think.

Quote:
What's the difference b/w 5.1 and 2.0 and all that surround sound stuff?


It's how many "channels" of sound are on the DVD. Each channel is a speaker in a home theatre system. So 2.0 is two channels, like a stereo (left and right). 5.1 is 5 channels (left, centre, right, left-rear, right-rear) and the .1 is meant to indicate a "sub-woofer" which is another speaker that makes really low sounding noises.

Hope this helps, though I'm sure I've been too technical.

You might also like to read:

How DVDs and DVD Players Work
How Home Theatre Works

- mib
Back to top
View user's profile Send private message
Weis
Meryl Strife


Joined: 14 Dec 2001
Posts: 8075
Location: A Dip in the Suburbs...

PostPosted: Tue Aug 05, 2003 11:43 pm    Post subject: Reply with quote
I'm just going off for a shower and going to bed (HSC trials tomorrow ^^), but I'll grab a couple of those for you.

NTSC has a higher bit rate than PAL (30 as opposed to 24), but PAL has more lines per screen.

Aliasing are the lines that... jitter I suppose would be the best word. Look at a straight diagonal line that is moving quickly on almost any anime DVD and you will see aliasing. It just seems to be something that plagues animation.

Artefacts are those dots, specks, holes the size of golf balls (if you watching DBZ movie 7). The annoying things you see always at the cinema.

Other glitches? Dropouts, the audio drops out momentarily. Distortions - something interferes with the quality of a peice of audio\video.

Anamorphic Widescreen 16:9 - The black bars you see above certain TV shows and on nearly all actual movie DVDs are widescreen. The idea is you get a more realistic impression of what the eye can see (or so its meant to be). Anamorphic I believe just means its flagged to work on widescreen tv's (like mine ^^) so there are no black bars and it fills the screen totally.

Dolby Digital 5.1 - Think of it as five different audio tracks, each being sent off to a different speaker (Centre - voice, Forward right and left, surround (rear) right and left). These work together to make you feel like your part of the action - directionality. The .1 of 5.1 represents the subwoofer which adds the thuds and the booms in the 'BOOMS'.
Dolby Digital 2.0 is just a soundtrack with the forward left and right channels only, though some of these can still use the rear channels.
DTS is just the same as DD 5.1 except its a different company and it uses a much higher bitrate for its sound. Because of this, not many DVDs can actually hold DTS and 5.1 soundtracks and because 5.1 is the mainstream, they drop DTS. DTS can also add a sixth channel (6.1) for the rear centre, which I believe is also used for voice.
The idea of surround is if someone is talking to the left, you hear it from the left. If a car explodes behind you, you here it from the rear speakers.

Hope thats cleared somethings up for you Smile
_________________
"Weis"

Warning: Use with caution.
Back to top
View user's profile Send private message Send e-mail Visit poster's website ICQ Number
Adrianw
Shinobu Nagumo


Joined: 11 Dec 2000
Posts: 498
Location: Perth, WA

PostPosted: Thu Aug 07, 2003 12:40 am    Post subject: Reply with quote
Weis wrote:
NTSC has a higher bit rate than PAL (30 as opposed to 24), but PAL has more lines per screen.

You mean "NTSC has a higher frame rate than PAL".

Weis wrote:
Anamorphic Widescreen 16:9 - The black bars you see above certain TV shows and on nearly all actual movie DVDs are widescreen. The idea is you get a more realistic impression of what the eye can see (or so its meant to be). Anamorphic I believe just means its flagged to work on widescreen tv's (like mine ^^) so there are no black bars and it fills the screen totally.

Each frame of a movie on a DVD is the regular TV shape (or 4:3). If a widescreen image is held on a non-anamorphic DVD then some of the 4:3 shape will contain black bars (a waste of space). Anamorphic means that all (or most) of this black space is used to hold more lines of the image - kind of stretched vertically - so people will look tall and skinny. A widescreen TV will stretch this image sideways to make it the correct aspect ratio again. If you have a 4:3 TV then your DVD player will throw away every fourth line of the image to get back to the proper ratio.

16:9 is equivalent to 1.78:1 - so if you have a 16:9 enhanced movie which is 1.78:1 aspect ratio then there will be no black lines stored on the DVD and no black bars will be displayed on a widescreen TV.

If the movie is wider than 1.78:1 (eg. 2.35:1, like Star Wars, The Matrix etc). Then there will still be some black bars encoded on the DVDs and even widescreen TV's will display black bars at the top & bottom (although they will be narrower than on a regular TV).
Back to top
View user's profile Send private message
Weis
Meryl Strife


Joined: 14 Dec 2001
Posts: 8075
Location: A Dip in the Suburbs...

PostPosted: Thu Aug 07, 2003 12:24 pm    Post subject: Reply with quote
Adrianw wrote:
If the movie is wider than 1.78:1 (eg. 2.35:1, like Star Wars, The Matrix etc). Then there will still be some black bars encoded on the DVDs and even widescreen TV's will display black bars at the top & bottom (although they will be narrower than on a regular TV).


Yes, I noticed that for Harry Potter 2 the other day. Still, beats watching it and losing half the picture on a 34cm! Argh, 16cm of screen!
_________________
"Weis"

Warning: Use with caution.
Back to top
View user's profile Send private message Send e-mail Visit poster's website ICQ Number
Zikea Shogun
Doraemon


Joined: 02 Aug 2003
Posts: 74
Location: Stealing ya Jam!

PostPosted: Thu Aug 07, 2003 3:08 pm    Post subject: Reply with quote
Weis ,............... What a dummy!
_________________
Arrrrr Ice Tea You are a Sweet and Refreshing Beverage........

You go to Prison!

Space Ghost-
Back to top
View user's profile Send private message MSN Messenger
Evil
Koishi Herikawa


Joined: 24 Feb 2003
Posts: 652
Location: Melbourne

PostPosted: Mon Aug 18, 2003 2:18 pm    Post subject: Reply with quote
Weis wrote:
NTSC has a higher bit rate than PAL (30 as opposed to 24), but PAL has more lines per screen.


NTSC can also be 28 FPS and PAL can also be 25 FPS (If you want to be technical Very Happy )
_________________
Its Not Easy Being Evil...
Back to top
View user's profile Send private message
Miyuki
Minawa Andou


Joined: 29 Jul 2003
Posts: 590
Location: Melbourne

PostPosted: Mon Aug 18, 2003 9:13 pm    Post subject: Reply with quote
Ara! I completely forgot about this thread ^^;;;

Gomen minna!

It was actually quite interesting to read even though I don't have an eye for these sorts of things ^^;;;

Thanx for the explanations everyone!
_________________
Held in young hands, that light is shivering.
I've wandered all this way,
Not even knowing your name.
Wandering to the edge of time.
Back to top
View user's profile Send private message
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Mon Aug 18, 2003 9:57 pm    Post subject: Reply with quote
Miyuki wrote:
Ara! I completely forgot about this thread ^^;;; Gomen minna!


I did wonder. Dou itashimashite.

- mib
Back to top
View user's profile Send private message
suzaku
Lin Minmay


Joined: 16 Jan 2002
Posts: 259
Location: CLAMP Campus, Milky Way

PostPosted: Sat Aug 23, 2003 10:31 am    Post subject: Reply with quote
Can we have a sticky thread for this topic. I find it very informative in terms of the technical side. Smile
_________________
You don't like my rice? What's wrong with it? It's beautiful to me! To you, it's just rice. To us, it's family. Don't f*ck with my family! If you have any dignity, apologize to my rice RIGHT NOW! (Chow Yun Fat)
Back to top
View user's profile Send private message Send e-mail
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Sat Aug 23, 2003 12:02 pm    Post subject: Reply with quote
If this is going to be sticky, I should correct some errors in the above posts lest they be repeated for all time:

Firstly, if you want to know about this topic, follow and read the links. It's just too long to explain it all here.




Weis wrote:
NTSC has a higher bit rate than PAL (30 as opposed to 24), but PAL has more lines per screen.


Weis is referring to the frame rate, not the bit rate.

Video (and this includes film at the cinema) works by showing a series of pictures quickly one after the other, fast enough that your eyes can't see any gap between them (which would cause the movie to flicker). Each picture is called a frame. Film (at the cinema) shows 24 frames per second. PAL video shows 25 frames per second. NTSC video shows 29.97 frames per second.[1]

Weis wrote:
Anamorphic I believe just means its flagged to work on widescreen tv's


Anamorphic means the picture has been "squashed" horizontally for storage on the DVD, and it is unsquashed for display. This allows you to store a widescreen image on a DVD without having to use some of the resolution to store the black bars at the top and bottom. Thus you get a more detailed picture.

Evil wrote:
NTSC can also be 28 FPS and PAL can also be 25 FPS (If you want to be technical


NTSC is definitely not 28 fps, it is 29.97.

- mib

[1] Actually, TVs are interlaced, which means half the vertical resolution is sent at twice the frame rate, so PAL is really 50 fields per second, and NTSC is 59.94 fields per second. A field is half of a frame (every second line).
Back to top
View user's profile Send private message
Tachikoma
Shiki Tohno


Joined: 21 Aug 2003
Posts: 5320
Location: Section-9, Melbourne

PostPosted: Sat Aug 23, 2003 12:26 pm    Post subject: Reply with quote
NTSC also supports 23.976Hz frame rates (apart from the 29.97Hz). The 23.976Hz frame rate was estabilished for film-to-NTSC transfers.


More about interlacing: TVs alternate the "even" or "odd" scanlines (or fileds) of a picture quite rapidly (ie. at twice the PAL/NTSC frame rates). Most video streams on DVDs are encoded in a similar fashion. DVDs also support a video encoding mode called "Progressive Scan". In this mode, the video is stored as non-interlaced - pretty much like digital film.

Cool
_________________
Overused memes.
Back to top
View user's profile Send private message Send e-mail
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Sat Aug 23, 2003 12:45 pm    Post subject: Reply with quote
Tachikoma wrote:
NTSC also supports 23.976Hz frame rates


No it doesn't. That frame rate is achieved with 3:2 pulldown, it's still displayed at 29.97 frames/sec.

- mib
Back to top
View user's profile Send private message
Tachikoma
Shiki Tohno


Joined: 21 Aug 2003
Posts: 5320
Location: Section-9, Melbourne

PostPosted: Sat Aug 23, 2003 1:24 pm    Post subject: Reply with quote
I've should have been more specific: The DVD specification allows NTSC video to be encoded at 23.976Hz or 29.97Hz. Thats what I meant.

But you're right, NTSC TVs always use the 29.97Hz frame rate for displaying. Smile




edit: grammar
_________________
Overused memes.
Back to top
View user's profile Send private message Send e-mail
Mystery Man v 2.0
Minawa Andou


Joined: 22 Jun 2003
Posts: 518
Location: Back from the grave.

PostPosted: Thu Nov 27, 2003 5:56 pm    Post subject: Reply with quote
Sorry, wrong thread. Very Happy
_________________
Hello. I'm back from the grave. Do you remember me? Wait...You don't? Well, **** you.
Back to top
View user's profile Send private message Visit poster's website
Issy
Mint Blancmanche


Joined: 15 Jan 2004
Posts: 1561
Location: GC QLD !!! ^_^

PostPosted: Wed Feb 11, 2004 7:23 pm    Post subject: Reply with quote
mib wrote:
Miyuki wrote:
Ara! I completely forgot about this thread ^^;;; Gomen minna!


I did wonder. Dou itashimashite.

- mib



lol you know your Japanese Very Happy
_________________
Still waiting,dreaming and wanting

PROJECT A-KO ^_^

AND IT FINALLY COMES THANKYOU MADMAN U R THE BEST...

ISSY IS HAPPY
Back to top
View user's profile Send private message Send e-mail MSN Messenger
Goto the Hobo
Doraemon


Joined: 13 Jan 2004
Posts: 28
Location: newcastle

PostPosted: Thu Feb 12, 2004 10:02 am    Post subject: Reply with quote
this may seem stupid to ask, but what's the advantage of having a higher frame rate of about 29.97 or thereabouts, when animation only uses about 25 fps max anyway?. wouldn't the effect be exactly the same anyway, since it's limited by the animations fram rate, not the ntsc/pal format?
Back to top
View user's profile Send private message
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Thu Feb 12, 2004 12:13 pm    Post subject: Reply with quote
Goto the Hobo wrote:
this may seem stupid to ask, but what's the advantage of having a higher frame rate of about 29.97 or thereabouts, when animation only uses about 25 fps max anyway?. wouldn't the effect be exactly the same anyway, since it's limited by the animations fram rate, not the ntsc/pal format?


Some animation uses 30fps native now, actually. Admittedly not much.

One advantage is that 60fps is less flickery to the eye than 50fps. This is more noticeable by some people than others.

The main problem is that if animation is made in 30fps or 24fps, there's no good way to turn it into 25fps animation without fudging it in some way.

- mib

[1] For simplicity I've used 30 instead of the 29.97 above.
Back to top
View user's profile Send private message
Issy
Mint Blancmanche


Joined: 15 Jan 2004
Posts: 1561
Location: GC QLD !!! ^_^

PostPosted: Fri Mar 05, 2004 11:45 pm    Post subject: Reply with quote
mib wrote:
Goto the Hobo wrote:
this may seem stupid to ask, but what's the advantage of having a higher frame rate of about 29.97 or thereabouts, when animation only uses about 25 fps max anyway?. wouldn't the effect be exactly the same anyway, since it's limited by the animations fram rate, not the ntsc/pal format?


Some animation uses 30fps native now, actually. Admittedly not much.

One advantage is that 60fps is less flickery to the eye than 50fps. This is more noticeable by some people than others.

The main problem is that if animation is made in 30fps or 24fps, there's no good way to turn it into 25fps animation without fudging it in some way.

- mib

[1] For simplicity I've used 30 instead of the 29.97 above.



jeez that is complicated Confused
_________________
Still waiting,dreaming and wanting

PROJECT A-KO ^_^

AND IT FINALLY COMES THANKYOU MADMAN U R THE BEST...

ISSY IS HAPPY
Back to top
View user's profile Send private message Send e-mail MSN Messenger
Proton
Doraemon


Joined: 28 Feb 2004
Posts: 49

PostPosted: Mon Jul 05, 2004 10:13 pm    Post subject: Flickery... Reply with quote
mib wrote:
Goto the Hobo wrote:
this may seem stupid to ask, but what's the advantage of having a higher frame rate of about 29.97 or thereabouts, when animation only uses about 25 fps max anyway?. wouldn't the effect be exactly the same anyway, since it's limited by the animations fram rate, not the ntsc/pal format?


Some animation uses 30fps native now, actually. Admittedly not much.

One advantage is that 60fps is less flickery to the eye than 50fps. This is more noticeable by some people than others.

The main problem is that if animation is made in 30fps or 24fps, there's no good way to turn it into 25fps animation without fudging it in some way.

- mib

[1] For simplicity I've used 30 instead of the 29.97 above.


It has been found that there are people who can discern flicker at frame rates up to 70Hz, which is why the VESA committee advocated the use of 72Hz refresh on computer screens. Interestingly, 72Hz is an exact multiple of 24Hz (the speed of cinema projectors) - if they made a TV or video projector operate at 72Hz it would be totally flicker-free, and could display films at the correct speed simply by showing every frame 3 times.

Given that a PC with DVD playing software can extract the frames from a DVD intact and display them progressively, it should be possible to show them at 72Hz.

I'm toying with the idea of building a Home Theatre PC to using to display DVDs at 72Hz on a CRT projector. All I need is the time to spend on the project Sad
Back to top
View user's profile Send private message
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Mon Jul 05, 2004 10:36 pm    Post subject: Re: Flickery... Reply with quote
Proton wrote:
It has been found that there are people who can discern flicker at frame rates up to 70Hz


There is a busted fluoro tube at Melbourne Central right opposite where I stand that flickers and drives me nuts that nobody else I know can tell is flickering. Smile

Quote:
if they made a TV or video projector operate at 72Hz it would be totally flicker-free, and could display films at the correct speed simply by showing every frame 3 times.


Pity about the majority of made-for-TV shows which here are 25fps and in the US are 29.97fps though. Sad

Quote:
Given that a PC with DVD playing software can extract the frames from a DVD intact and display them progressively, it should be possible to show them at 72Hz.


You're assuming that the DVD is encoded properly with all the progressive flags set so that the original 24fps movie can be easily extracted. For Hollywood movies this is somewhat likely; for anime is it almost unheard of. PCs are not sufficiently powerful (I'm told) to do proper cadence reading deinterlacing (such as faroudja chips do in projectors and some DVD players) and extract the 24fps signal from a badly flagged DVD MPEG stream.

Quote:
I'm toying with the idea of building a Home Theatre PC to using to display DVDs at 72Hz on a CRT projector. All I need is the time to spend on the project Sad


I'd suggest going to avsforum.com and having a read up on projectors and in particular on progressive scan and deinterlacing chips in projectors.

See also: http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html and the associated shootout scoreboard.

Sadly the situation is probably more complicated than you suspect. Most of the time I don't think I've gotten my head around it and I've been interested and reading up for 2 years now.

- mib
Back to top
View user's profile Send private message
Tachikoma
Shiki Tohno


Joined: 21 Aug 2003
Posts: 5320
Location: Section-9, Melbourne

PostPosted: Mon Jul 05, 2004 11:03 pm    Post subject: Reply with quote
Man, we need to overhaul this NTSC/PAL crap and standardise to progressive HDTV around the world.
_________________
Overused memes.
Back to top
View user's profile Send private message Send e-mail
Proton
Doraemon


Joined: 28 Feb 2004
Posts: 49

PostPosted: Sat Oct 02, 2004 8:53 am    Post subject: Re: Flickery... Reply with quote
mib wrote:
...
Quote:
if they made a TV or video projector operate at 72Hz it would be totally flicker-free, and could display films at the correct speed simply by showing every frame 3 times.


Pity about the majority of made-for-TV shows which here are 25fps and in the US are 29.97fps though. Sad

Quote:
Given that a PC with DVD playing software can extract the frames from a DVD intact and display them progressively, it should be possible to show them at 72Hz.


You're assuming that the DVD is encoded properly with all the progressive flags set so that the original 24fps movie can be easily extracted. For Hollywood movies this is somewhat likely; for anime is it almost unheard of. PCs are not sufficiently powerful (I'm told) to do proper cadence reading deinterlacing (such as faroudja chips do in projectors and some DVD players) and extract the 24fps signal from a badly flagged DVD MPEG stream.

... - mib


According to some of my reading, PCs have reached "powerful enough" now. The latest machines are fast enough, and have enough memory, that they can do cadence reading, and the various cool bits (that's techno talk). Apparently the breakthrough was when someone thought of holding several frames (I think they use about 8 frames) in memory so they can do the work on the frames in the buffer while feeding the display the tail of the buffer. 8 frames is only a fraction of a second, so it's not especially noticeable in terms of delaying the start of play, but it's enough to give the analysis routines time to work out the appropriate mode of operation.

Apparently some of those VERY expensive DVD players (the ones for $8k+) are really PCs, anyway.
Back to top
View user's profile Send private message
mib
Ayeka Masaki Jurai


Joined: 04 Nov 2001
Posts: 6463

PostPosted: Sat Oct 02, 2004 9:57 am    Post subject: Re: Flickery... Reply with quote
Proton wrote:
According to some of my reading, PCs have reached "powerful enough" now. The latest machines are fast enough, and have enough memory, that they can do cadence reading, and the various cool bits (that's techno talk).


What is the name of the DVD playing software that supports this? I must know!

- mib
Back to top
View user's profile Send private message
Display posts from previous:      

Page 1 of 1


Jump to:  

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum