Are DVDs really 480p? 480p vs. 720p question. - Page 2 - AVS Forum
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post #31 of 145 Old 06-28-2014, 02:17 PM
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Hey, Stereodude. Can I ask you some questions?

Quote:
Originally Posted by Stereodude View Post
Most recent DVDs of movies that were shot on "film" are actually encoded at 720x480p @23.976FPS and have a soft pulldown applied to them.
Yes, I was aware of that. The Sony Pictures DVD of "Enigma" that is giving me difficulties is such a case.

All I have is MPC-HC (Media Player Classic-Home Cinema -- which gives me flaky disc statistics -- and CyberLink PowerDVD 10 -- which of course gives me no disc statistics and is as dumb as a box of rocks.

I can't trust what MPC-HC tells me because it obviously is not well designed: If I pause a DVD and later resume, the indicated frame rate drops into the dirt. MPC-HC apparently calculates frame rate based on absolute time, not play time (which doesn't include time in pause). Skipping around the disc also screws up the indicated frame rate. Nevertheless, when I play "Enigma" (without pausing) from the beginning, the frame rate goes up toward 28fps, then drifts down toward about 24.5fps, then drifts up again past 25fps, then continues to drift up and down for a while, then after about 20 minutes settles at 23.98fps.

Another point of confusion is that MPC-HC says this: "720x480 60Hz 16:9", even though it says that the frame rate is 23.98. It is very frustrating not knowing what the Hell is going on. Since the Sony technicians say there's nothing wrong with the "Enigma" disc, I expect that the only way Sony will be forced to replace the disc is to shame them into it, but to do that I need a tool and some reliable statistics.

The "Enigma" disc looks okay when played by MPC-HC on my Dell 1440x900 laptop screen. But on my Panasonic 1920x1080p Home Theater, it exhibits severe combing in some scenes while others look okay. The combing is so bad that it looks like the field order is backwards - I worked as a development engineer at Atari in the early 80s, so I did a lot of experimentation of NTSC, including what field-reversal looks like.

I haven't been able to correlate the scenes-with-combing with the scenes-with-frame-rate-drift because I'm hoping to find a software tool that will help me. Do you know of any?

Quote:
Originally Posted by Stereodude View Post
...or it can apply the telecine as flagged and then apply an inverse telecine in the player's video processor to remove the telecine getting back the same 480p23.976 video stream.
"it" means the DVD player, right? I think you're saying that the player might apply a 3-2 pull-down to 30fps and then reverse it back to 24fps? Why would it do that? How can I discover what it's doing?

Quote:
Originally Posted by Stereodude View Post
If your DVD player doesn't support progressive playback you're going to get the telecined 480i59.97 output.
Where did 59.97fps come from? Without hooking up my o'scope, how could I tell? BTW, I absolutely know that the Panasonic Home Theater supports 1080p@60Hz. And, BTW, the Vizio True-HD TV is 60Hz only! It does not support 24fps.

So, you see, I'm between a rock and a hard place. Sony says there's nothing wrong with the DVD. Panasonic says there's nothing wrong with the Home Theater (and "No", they don't want me to send the DVD for their oh-so-busy technicians to play with). Without some tool to read the disc and to monitor the stream while the disc is playing in my computer, I can't crack this nut.

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post #32 of 145 Old 06-28-2014, 02:38 PM
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MediaInfo should be able to tell the frame rate (plus a few other stats) of a video file/DVD.

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post #33 of 145 Old 06-28-2014, 03:00 PM
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Quote:
Originally Posted by markfilipak View Post
Where did 59.97fps come from?
I think he meant approx 59.94 fields per second (approx 29.97 * 2). 60*(1000/1001)=59.94005994... So normal NTSC TV runs at approx 59.94 fields per sec since the introduction of colour (before that NTSC TV was exactly 60.0 fields per sec), and an "NTSC" DVD may be encoded at approx 59.94i (29.97 fps).

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post #34 of 145 Old 06-28-2014, 03:33 PM
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Quote:
Originally Posted by markfilipak View Post
Hey, Stereodude. Can I ask you some questions?
It could be partially hard telecined mixed with soft telecined material. There could be true interlaced material in there or improperly converted film content. It's hard to say. You would need to decrypt the disc on your PC and analyze the movie if you really want to know what's going on.
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post #35 of 145 Old 06-28-2014, 03:41 PM
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Quote:
Originally Posted by Stereodude View Post
You would need to decrypt the disc on your PC and analyze the movie if you really want to know what's going on.
Which would probably be illegal wouldn't it (decrypting the disc to an unencrypted version)?

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post #36 of 145 Old 06-28-2014, 03:47 PM
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Quote:
Originally Posted by Joe Bloggs View Post
Which would probably be illegal wouldn't it?
Maybe, if he's overly worried about that sort of thing. There is no other way he's going to find out what's really going on though.
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post #37 of 145 Old 06-28-2014, 03:54 PM
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Quote:
Originally Posted by Stereodude View Post
Maybe, if he's overly worried about that sort of thing. There is no other way he's going to find out what's really going on though.
So assuming it was currently illegal (which it may probably be), he is doing this (trying to find out what, if anything is wrong with the DVD) so he can say to the the company "this disc is encoded wrong (because..)...". He can't really do that - decrypt, analyse, find out something is flagged wrong or whatever and say to the company "this is flagged wrong, can it be replaced/fixed?" or whatever, since they would then likely say "by decrypting the DVD we made, to then analyse it to find out this was flagged wrong you've probably broken the DMCA..." and they'd then have evidence of probable breaking of the law (circumventing the DMCA). I suppose he could request permission from the copyright owner to allow him to circumvent it (so it was authorized and not breaking the law) for the sole purpose of checking but aren't they just going to say no?

Surely it's better to just accept the disc/try it on a different player/try buying a different version. But I think it would be a very bad idea to attempt to find out if it is flagged incorrectly to tell them so if doing so has any chance of breaking some law (eg. DMCA).

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post #38 of 145 Old 06-28-2014, 04:09 PM
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Quote:
Originally Posted by Joe Bloggs View Post
Which would probably be illegal wouldn't it (decrypting the disc to an unencrypted version)?
There is no criminal intent. Without criminal intent there can be no crime. This is my copy, legally obtained. If I choose to decrypt it in order to discover what is wrong, there's nothing per se illegal about that. I don't care what the law says. In a court, criminal intent must be proven. That I actually own the DVD should make criminal intent moot.

What tools do I need?

-- EDIT --
Removed extras to return to original posting.
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post #39 of 145 Old 06-28-2014, 04:50 PM
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Hey! Wait a minute! Can't I see what's wrong simply by analyzing the video stream? It occurs to me that I'd at least be able to infer deinterlace errors.

What do I need to run in order to intercept & analyze the video stream?

-- EDIT --
No answer? ...By "video stream" I mean just prior to the HDMI output. Now, any help?

Thank you.

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post #40 of 145 Old 06-28-2014, 08:11 PM
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Use DVD Decrypter to copy the movie to your HD. You will want to use .IFO mode. Then use DGMPGDec to open the .vob file(s) and you can play it, which will open up a window with some info on it as it plays, or you can save an index file which will process it quite quickly and show you stats on the movie. Framerate, % of it that's film, etc.
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post #41 of 145 Old 06-29-2014, 05:58 AM
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DVD deinterlaceing isn't exactly an easy task. It requires complicated algorithms and often dedicated hardware chips. Most PC software are bad at it. So are most cheap DVD players or BD players. The reason is a lot of discs are badly authored and confuse the simple deinterlacers. The result is comb effects on screen. Replace the disc will not be helpful because all discs are the same due to authoring error.

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post #42 of 145 Old 06-29-2014, 06:37 AM
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Quote:
Originally Posted by Foxbat121 View Post
DVD deinterlaceing isn't exactly an easy task. It requires complicated algorithms and often dedicated hardware chips. Most PC software are bad at it. So are most cheap DVD players or BD players. The reason is a lot of discs are badly authored and confuse the simple deinterlacers. The result is comb effects on screen. Replace the disc will not be helpful because all discs are the same due to authoring error.
Replacing the disc could be helpful if it's a different version (different encoding) that doesn't have the encoding problem (if there is one) eg. he said "Sony released a completely new Region 1 DVD (new telecine?) only one year later".
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post #43 of 145 Old 06-29-2014, 06:43 AM
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It rarely ever happened. And there is no guarantee that new version doesn't have the same or new problems.

Back in the old days, you often need to shell out $1500 for a top end DVD player with dedicated chip to correctly deinterlace these discs.
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post #44 of 145 Old 06-29-2014, 08:02 AM
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Quote:
Originally Posted by Foxbat121 View Post
DVD deinterlaceing [...] requires complicated algorithms and often dedicated hardware chips. Most PC software are bad at it. So are most cheap DVD players or BD players. The reason is a lot of discs are badly authored and confuse the simple deinterlacers. The result is comb effects on screen. Replace the disc will not be helpful because all discs are the same due to authoring error.
This:
Enigma by Sony Pictures/Columbia TriStar Home Entertainment
CAT# 08734, UPC 043396087347

(which I own) was succeeded by this:
Enigma by Sony Pictures/Columbia TriStar Home Entertainment
CAT# 00749, UPC 043396007499

about a year later. Why do you suppose Sony would do that for such a small film? I want to investigate my copy for evidence to force (or shame) Sony to replace it with the newer transfer. Manufacturers should be forced to recall defective product. Try to contact Sony about this... You can't. They have no way to contact them via anything you can find on their site. If you do find a phone number and phone Sony, they tell you to contact the factory that pressed the DVD and then they hang up on you. I'm not kidding. That has happened to me and to others who I've found through Internet searches. That kind of behavior has to end and I have the time and knowledge and inclination to force the situation.
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post #45 of 145 Old 06-29-2014, 08:55 AM
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Quote:
Originally Posted by SpeksETC View Post
I always thought DVDs were 480p, which is considered SD and thats why 720p material looked so much better.

Yesterday I went to www.apple.com/trailers and saw that not only do they categorize their 480p trailers as HD, but when I watched a 480p trailer on my Panny 50PV80, it looked pretty damn good, and definitely better than a standard DVD.
What is going on here?

Try it for yourself:

http://movies.apple.com/movies/unive...tlr2_h480p.mov

http://movies.apple.com/movies/unive...tlr2_h720p.mov
Sorry for quoting an old post, but I've pointed out the same thing many times here and elsewhere in the past 10+ years.

The CEA gave 480p its own designation- EDTV vs SD and HD

https://en.wikipedia.org/wiki/Enhanc...ion_television

http://www.projectorcentral.com/vide...rlacing-Issues

But I agree with Apple here- I think well mastered, high detail 480p video from quality progressive sources (film or progressive scan cameras) can easily be classified as "HD".

Taking the width of typical anamorphic 35mm film stock
https://en.wikipedia.org/wiki/35_mm_film

of .864", then at 720 pixels horizontally per DVD resolution:

720/.864 ~ 833dpi

I'm pretty happy knowing well mastered DVD's easily have > 600dpi renditions of the film stock
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post #46 of 145 Old 06-29-2014, 09:45 AM
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Quote:
Originally Posted by Rgb View Post
Sorry for quoting an old post, but I've pointed out the same thing many times here and elsewhere in the past 10+ years.

The CEA gave 480p its own designation- EDTV vs SD and HD

https://en.wikipedia.org/wiki/Enhanc...ion_television

http://www.projectorcentral.com/vide...rlacing-Issues

But I agree with Apple here- I think well mastered, high detail 480p video from quality progressive sources (film or progressive scan cameras) can easily be classified as "HD".

Taking the width of typical anamorphic 35mm film stock
https://en.wikipedia.org/wiki/35_mm_film

of .864", then at 720 pixels horizontally per DVD resolution:

720/.864 ~ 833dpi

I'm pretty happy knowing well mastered DVD's easily have > 600dpi renditions of the film stock
The dpi of the telecine when scaled to the film source is not material. What is material is the solid angle of view per pixel in the displayed image. Human luminance perception sets an upper limit at about 1 arc-minute (1'). A display that's 6 feet away and that fills a 90 degree field of view with 1 arc-minute of resolution is a 12 foot wide display having 5400 pixels horizontally and a dot pitch of 38dpi. Would you consider 38dpi to be HD? Believe me. If you saw the display I just described, you'd be blown away.

EDIT: On second thought, Rgb, perhaps you have telecine experience and know that 833dpi (lines/inch, actually) on a 35mm film frame is good resolution. My experience is at the display end, not the sampling end, so I apologize for any impression that what you wrote may be erroneous. It probably isn't. Ciao.

MORE EDIT: One arc-minute is the apparent width of a hair held at arm's length or of a grain of sand seen from across a 2-lane city street or of a pea seen from across a football pitch.

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post #47 of 145 Old 06-29-2014, 10:26 AM
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Are there many DVDs encoded at 24 fps progressive? I've never seen one that wasn't interlaced.

Many cheaper Blu-ray players can't telecine 1080p24 content to 1080i60 correctly. So if they cut corners with a Blu-ray player chances are many DVD players are the same.

It can be better to buy a 576i version of a DVD and play it slowed down by 4% than buy the 480i version with lower resolution and undefeatable jitter.

DVDs are restricted to 10 megabits not 5. Many are encoded at 5 but there is a huge quality boost closer to 10. I've seen DVDs encoded at as low as 1.75 megabits.
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Quote:
Originally Posted by homerging View Post
Are there many DVDs encoded at 24 fps progressive? I've never seen one that wasn't interlaced.
How would someone know this, homerging?
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post #49 of 145 Old 06-29-2014, 10:56 AM
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Quote:
Originally Posted by homerging View Post
Are there many DVDs encoded at 24 fps progressive? I've never seen one that wasn't interlaced.
The answer is a bit complicated. From what I've seen it seems most recent DVDs of Hollywood movies have a 480p23.976 MPEG-2 stream with a soft pulldown flag on the disc. If your DVD player is performing per the specs the decoder in it shouldn't pass the progressive stream. It's supposed to apply the 3:2 telecine to the content per the flag in the video stream. That's probably why you've never seen one that wasn't interlaced.

However, some PC based playback solutions intentionally don't honor the soft pulldown flag and pass the decoded MPEG-2 video as progressive. Also some high end DVD players had fairly sophisticated video processors from Faroudja, Silicon Optix, or similar that would apply an inverse telecine to the video stream if it detected 3:2 film content (this losslessly gets back to the progressive MPEG-2 stream on the disc), or sophisticated vector based deinterlacing for true video content. They could also scale the video to higher resolutions. These players could pass progressive 23.976fps or 59.94fps video from their outputs.

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post #50 of 145 Old 06-29-2014, 10:58 AM
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Quote:
Originally Posted by markfilipak View Post
How would someone know this, homerging?
You'd have to decrypt the disc and look at the MPEG-2 stream to see if it's got a soft or hard 3:2 pulldown applied to it, or alternatively use a playback method that doesn't honor the soft pulldown flags. In the latter case if you get 480p23.976 it's "soft". If you get 480i59.94 it's "hard" (or not film based content).
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post #51 of 145 Old 06-29-2014, 11:23 AM
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The sharpness of an image is not just the limiting resolution of the format, but rather a frequency response curve. An image with a lower pixel count but flatter frequency response can look subjectively sharper than one with gradual high frequency roll-off.

Real time film transfers have largely been replaced by film scanning at higher resolutions. With the Digital Intermediary (DI) workflow, the camera film negative is scanned and subsequent editing and grading (color correction) is performed in the digital domain. This can then be converted into distribution formats for digital cinema and consumer video. Compare that to the traditional film workflow which was to first physically cut and splice the camera negative together based on editing decisions made by cutting together work prints made from the camera negative, making an intermediate negative of the spliced camera negative (now being positive hence the term interpositive or just IP) which is color timed (color corrected), then making a intermediate negative of that (IN) and then creating the distributed projection prints from the IN. The IP was normally used for telecine transfers.

While real time film transfers could yield high quality images, there was unfortunately a lack of uniformity. It wasn't too uncommon to see excessive mid frequency boost by use of detail enhancement causing outlines (referred to by many here as Edge Enhancement) which could actually mask finer high frequency detail. Film scanning has pretty much replaced film transfers. As digital acquisition for principle photography increases in usage, the only film involved may be 'film outs' which is outputting the digital images to film for traditional theaters.

As mentioned the optimal method for DVD encoding of 24fps material is effectively 24p encoding with subsequent output in 480p or 480i (576 in 625 systems). Even if the output is in 480/60i, some displays (probably most now) can recognize the pulldown pattern and treat the image as progressive rather than interlaced. Obviously MPEG2 is far less efficient than h.264 (and now HEVC) and requires a higher data rate to preserve quality.

Horizontal resolution in lines takes aspect ratio into account. Therefore 720 pixels in 4:3 yields 720*3/4 = 540 lines. This is the maximum theoretical resolution, but the practical resolution is less as anti-alias low pass filters do not have an infinite slope. For 16:9 SD the maximum theoretical horizontal resolution is 720*9/16= 405 lines. In either case the pixels are not rectangular square (such as in HD formats) but are thin in 4:3 and wide in 16:9.

Last edited by TVOD; 06-29-2014 at 03:20 PM. Reason: fixed rectangular to square
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post #52 of 145 Old 06-29-2014, 12:02 PM
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Quote:
Originally Posted by Stereodude View Post
The answer is a bit complicated. From what I've seen it seems most recent DVDs of Hollywood movies have a 720p23.976 MPEG-2 stream with a soft pulldown flag on the disc.
Huh? Is that a typo, Stereodude? Don't you mean 480p23.976?

I'm totally mystified now.

Please correct my notions, below.

480i @(60/1.001)Hz = NTSC-compatible digital video source consisting of 2, 240-line fields that are both spacially & temporally interlaced.

480p @24Hz = progressive telecine from a film source having 480-line frames.

480p @(24/1.001)Hz = 480p @24Hz source slowed by 0.1% to prepare the timing for NTSC compatibility.

480p @(30/1.001)Hz = 480p @(24/1.001)Hz source with applied 3-2 pull-down.

480i @(60/1.001)Hz = 480p @(30/1.001)Hz source consisting of 2, 240-line fields that are spacially (but not temporally) interlaced.

How can a DVD player tell the top 480i @(60/1.001)Hz condition from the bottom 480i @(60/1.001)Hz condition?

-- EDIT --
I guess I should write: "How can a deinterlacer tell the top 480i @(60/1.001)Hz condition from the bottom 480i @(60/1.001)Hz condition?"

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post #53 of 145 Old 06-29-2014, 12:09 PM
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Quote:
Originally Posted by TVOD View Post
Horizontal resolution in lines takes aspect ratio into account. Therefore 720 pixels in 4:3 yields 720*3/4 = 540 lines. This is the maximum theoretical resolution, but the practical resolution is less as anti-alias low pass filters do not have an infinite slope. For 16:9 SD the maximum theoretical horizontal resolution is 720*9/16= 405 lines. In either case the pixels are not rectangular (such as in HD formats) but are thin in 4:3 and wide in 16:9.
It seems to me you're using 720 pixel horizontal resolution to determine vertical line resolution. How can you do that?

DVDs have 480 (or 576) lines, not 540 lines. The DVD storage pixels (i.e., PAR) are not square. What does that have to do with number of horizontal lines?
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post #54 of 145 Old 06-29-2014, 12:25 PM
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Quote:
Originally Posted by markfilipak View Post
Huh? Is that a typo, Stereodude? Don't you mean 480p23.976?
Yes, it was a typo.

Quote:
Originally Posted by markfilipak View Post
I'm totally mystified now.

Please correct my notions, below.

480i @(60/1.001)Hz = NTSC-compatible digital video source consisting of 2, 240-line fields that are both spacially & temporally interlaced.

480p @24Hz = progressive telecine from a film source having 480-line frames.

480p @(24/1.001)Hz = 480p @24Hz source slowed by 0.1% to prepare the timing for NTSC compatibility.

480p @(30/1.001)Hz = 480p @(24/1.001)Hz source with applied 3-2 pull-down.

480i @(60/1.001)Hz = 480p @(30/1.001)Hz source consisting of 2, 240-line fields that are spacially (but not temporally) interlaced.

How can a DVD player tell the top 480i @(60/1.001)Hz condition from the bottom 480i @(60/1.001)Hz condition?

-- EDIT --
I guess I should write: "How can a deinterlacer tell the top 480i @(60/1.001)Hz condition from the bottom 480i @(60/1.001)Hz condition?"
Some can, some can't. Technically the last one is progressive. The deinterlacing algorithms shouldn't find any combing.
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post #55 of 145 Old 06-29-2014, 12:54 PM
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Originally Posted by TVOD View Post
...In either case the pixels are not rectangular (such as in HD formats)...
The pixels in HD formats are square, not rectangular.
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post #56 of 145 Old 06-29-2014, 12:59 PM
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Originally Posted by TVOD View Post
...720 pixels in 4:3 yields 720*3/4 = 540 lines...For 16:9 SD the maximum theoretical horizontal resolution is 720*9/16= 405 lines...
I'm sorry, but this looks like nonsense to me. Can anyone clue me into what TVOD is trying to convey?

Thank you.
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post #57 of 145 Old 06-29-2014, 01:04 PM
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Originally Posted by markfilipak View Post
The pixels in HD formats are square, not rectangular.
I agree, except one I can think of is 1440x1080 HD (16:9 screen format) format which isn't square.

Last edited by Joe Bloggs; 06-29-2014 at 01:32 PM. Reason: fixed typo/error in resolution
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post #58 of 145 Old 06-29-2014, 01:20 PM
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Originally Posted by markfilipak View Post
I can't trust what MPC-HC tells me because it obviously is not well designed: If I pause a DVD and later resume, the indicated frame rate drops into the dirt. MPC-HC apparently calculates frame rate based on absolute time, not play time (which doesn't include time in pause). Skipping around the disc also screws up the indicated frame rate. Nevertheless, when I play "Enigma" (without pausing) from the beginning, the frame rate goes up toward 28fps, then drifts down toward about 24.5fps, then drifts up again past 25fps, then continues to drift up and down for a while, then after about 20 minutes settles at 23.98fps.
I used MPC-HC to look at the frame rate, etc after I built my HTPC that used integrated Intel graphics. This was mainly on OTA recordings & the fps were always changing. I did check a DVD & recall that it too did not have a steady frame rate. These irregularities were not noticeable when watching TV. Then I added an HD6450 video card & then MPC-HC indicated a steady frame rate.

Perhaps what you're seeing in MPC-HC is related to the video graphics of your PC.

WMC can also display quite a bit of data. I know it will indicate the source resolution but am not sure about other source data. You may want to try it. Press 4-1-1-Ctrl "D" while playing the DVD in WMC.
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post #59 of 145 Old 06-29-2014, 01:22 PM
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Originally Posted by markfilipak View Post
I'm sorry, but this looks like nonsense to me. Can anyone clue me into what TVOD is trying to convey?

Thank you.
He's talking about "lines per picture height" or "TV lines per picture height" - how much can be resolved by a particular system. Though I think it was something more used for analogue formats not digital.

http://www.afterdawn.com/glossary/te...picture_height
Quote:
Lines per Picture Height refers to the number of TV Lines an analog TV can display in a 1:1 area of the screen

Last edited by Joe Bloggs; 06-29-2014 at 01:27 PM.
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post #60 of 145 Old 06-29-2014, 01:31 PM
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Originally Posted by markfilipak View Post
Joe,
What media has 1920x1440 frames? That is, what media has SAR=4:3?
Sorry that was a typo. I meant 1440x1080. Which was used by some HD cameras, the BBC for broadcasts and is one of the resolutions in the Blu-ray spec.
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