TV Signal Compression In The Real World - Page 4 - AVS Forum
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post #91 of 274 Old 08-12-2013, 05:31 AM
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Originally Posted by 8mile13 View Post

Lets just say there are 195 countries, on that list there are only 50 countries, so much is missing. One of them is Utopolis in Luxembourg smile.gif

Good of you, you did the counting. smile.gif
I had hoped somebody would have counted the number of screens too. tongue.gif

Warner should have been responsible to make a complete list as they know the real number of HFR screens based on the number of HFR copies of The Hobbit they distributed.
Seems like Warner is much too USA centric.

The list is a "labour of love" very much based on people providing the cinemas for their country. I guess no Lëtzebuerger has cared to report in their HFR screens, now is your chance. wink.gif

When the next Hobbit part is closer to release hopefully we will see some more activity and the list getting updates.
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post #92 of 274 Old 08-13-2013, 12:00 PM
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Originally Posted by StinDaWg View Post

LOL, I don't think I've ever seen the phrase "shoot off the hip" so many times in one thread. This gregzoll is a real riot. 90% of what he's stating in this thread is incorrect, and yet we are just "shooting off the hip" and need to do some research. Ah, gotta love the internet. smile.gif

I don't understand why characters like this are even allowed in a tech forum like this, Where are the mods, If I was a mod I would have showed him the door way before he even reaches the 10th post.
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post #93 of 274 Old 08-13-2013, 12:07 PM
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Originally Posted by latreche34 View Post

I don't understand why characters like this are even allowed in a tech forum like this, Where are the mods, If I was a mod I would have showed him the door way before he even reaches the 10th post.

 

Use the flag button if someone really bothers you.  This is just an very annoying character defect though....not worth a moderator interceding for.


Java developers, when I saw what has been placed into Java 8 I was immediately reminded of how I've spent so much of my life trying to protect engineers from themselves. Lambda expressions are a horrible idea. Gentlemen: the goal isn't to make code readable for a competent mid-level engineer. The goal is to make code readable for a competent mid-level engineer exhausted and hopped up on caffeine at 3 am. What a disaster Java 8 is!
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post #94 of 274 Old 08-16-2013, 01:18 AM
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Originally Posted by gregzoll View Post

There is nothing being filmed in 1080p/24 or converted to 1080i30 for broadcast. All material will be filmed for the majority in 720p, the rest in 1080i. They may process those shows in 1080p, but they are not filmed in 1080p, due to it would eat up bandwidth downstream. May want to actually go out and look at what the broadcasters that show those shows, send it out to the consumers at the end.

Yes, on Blu-Ray, they will keep the same format those shows were filmed in, when mastered on the discs, but there is currently no way that providers can send out 1080p to their consumers, with the exception of DirecTV through their OnDemand.

This is grossly incorrect. 1080/24p has been the standard for episodic HDTV since 2000. The process was developed by Laser Pacific Media Corp in 1999. I was part of the R&D team! 1080/24p requires less bandwidth than 1080i or720p. Do the math if you can. The whole reason for 1080P/24 was the ability to have a single master that not only satisfied both CBS and ABC delivery requirements, but also satisfied future 50hz European requirements, both for SDTV conversions and future HDTV.

Further in the details, pure 24p is rarely used in TV work. The system is actually a segmented frame that is compatible with interlaced systems. The capture is progressive but the transmission in a 24 frame plant is on odd and even fields. And on top of that it's mostly 23.98 not 24.0 As of late, most DCI work is done at 24.0 in true progressive but not HDTV which is still 23.98sF. The reason for that is the continued support for 59.94 systems. The Europeans have long accepted the 4% offset this causes.

BluRay can support 23.98 and 24.0 but only in progressive. Sf is not supported on BluRay.
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post #95 of 274 Old 08-16-2013, 09:58 PM
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Originally Posted by Glimmie View Post

BluRay can support 23.98 and 24.0 but only in progressive. Sf is not supported on BluRay.
What is meant by "Sf is not supported by BluRay" do you mean only for 23.976/24.0 formats? Is progressive segmented frames not supported in the 30i and 50i Blu-ray formats (for 30p in 60i or 25p in 50i content) ?
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post #96 of 274 Old 08-16-2013, 10:07 PM
 
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Originally Posted by Joe Bloggs View Post

What is meant by "Sf is not supported by BluRay". Is progressive segmented frames not supported in the 30i and 50i Blu-ray formats (for 30p in 60i or 25p in 50i content) ?
Read through this http://en.wikipedia.org/wiki/Progressive_segmented_frame It explains what Glimmie is talking about. Then read http://en.wikipedia.org/wiki/SMPTE_292M then see http://en.wikipedia.org/wiki/High-definition_video Anything else, you are on your own, if you wish to research further.

Really instead of having everyone answer your questions on here, it helps to do your own homework Joe.
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post #97 of 274 Old 08-16-2013, 10:14 PM
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Originally Posted by gregzoll View Post

Read through this http://en.wikipedia.org/wiki/Progressive_segmented_frame It explains what Glimmie is talking about. Then read http://en.wikipedia.org/wiki/SMPTE_292M then see http://en.wikipedia.org/wiki/High-definition_video Anything else, you are on your own, if you wish to research further.

Really instead of having everyone answer your questions on here, it helps to do your own homework Joe.
I know what progressive segmented frames is thanks. I was questioning what was meant by "Sf is not supported by BluRay". Isn't progressive segmented frames used on Blu-ray for programmes that contain mostly 25p footage?
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post #98 of 274 Old 08-17-2013, 03:38 AM
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thread cleanup

please take the high road in every post
if you see a problematic post, please do not quote it or respond to it: report it to the mods to handle
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post #99 of 274 Old 08-17-2013, 05:21 AM
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Originally Posted by Joe Bloggs View Post

I know what progressive segmented frames is thanks. I was questioning what was meant by "Sf is not supported by BluRay". Isn't progressive segmented frames used on Blu-ray for programmes that contain mostly 25p footage?

They are two different things.

1) There are HD-SDI formats and frame rates.

2) There are compressed video formats and frames rates. In this case, they are constrained by the Blu-Ray specification.

The compressed video encoder (MPEG-2, H.264, whatever) decides how each HD-SDI input format and frame rate gets encoded into a compressed video format and frame rate.

1) For 23.976 and 24.0 PsF on HD-SDI, the encoder knows that it should capture the video in interlaced format (that is, weave the two fields into a progressive frame), and then encode the video as 23.976 or 24.0 fps progressive.

2) For 25p video, it's a little more complex. The Blu-Ray format only allows 25i, so the encoder has to output a 25i bit-stream. In this case, the HD-SDI source is set for 25i and the encoder encodes that at 25i. The only trick here is that the HD-SDI source is sending progressive frames as interlace. But the HD-SDI source doesn't care. Frame are just a collection of samples, and it doesn't know if the actual content is progressive or interlaced.

The encoder creates a 25i bit-stream, but since the actual content is progressive it will choose progressive encoding modes and the bit-stream will be just slightly less efficient than a regular 25p bit-stream.

Now you could send the 25p source as 25PsF (yes, 25PsF also exists on HD-SDI), but the encoder would do the same thing as 23.976 and 24.0 PsF. That is, weave the two fields into a progressive frame and then encode the video as 25 fps progressive.

From the HD-SDI point of view, sending 25p source as 25i or 25PsF is exactly the same thing. From the encoders point of view, 25i input gets coded as 25i and 25PsF input gets encoded as 25p.

Ron
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post #100 of 274 Old 08-17-2013, 11:20 AM
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Originally Posted by dr1394 View Post

The Blu-Ray format only allows 25i
50i - there are 50 interlaced fields. 25i would be 12.5fps. (or 25fps at half resolution)
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post #101 of 274 Old 08-17-2013, 12:26 PM
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Originally Posted by dr1394 View Post

They are two different things.

1) There are HD-SDI formats and frame rates.

2) There are compressed video formats and frames rates. In this case, they are constrained by the Blu-Ray specification.

The compressed video encoder (MPEG-2, H.264, whatever) decides how each HD-SDI input format and frame rate gets encoded into a compressed video format and frame rate.

1) For 23.976 and 24.0 PsF on HD-SDI, the encoder knows that it should capture the video in interlaced format (that is, weave the two fields into a progressive frame), and then encode the video as 23.976 or 24.0 fps progressive.

2) For 25p video, it's a little more complex. The Blu-Ray format only allows 25i, so the encoder has to output a 25i bit-stream. In this case, the HD-SDI source is set for 25i and the encoder encodes that at 25i. The only trick here is that the HD-SDI source is sending progressive frames as interlace. But the HD-SDI source doesn't care. Frame are just a collection of samples, and it doesn't know if the actual content is progressive or interlaced.

The encoder creates a 25i bit-stream, but since the actual content is progressive it will choose progressive encoding modes and the bit-stream will be just slightly less efficient than a regular 25p bit-stream.

Now you could send the 25p source as 25PsF (yes, 25PsF also exists on HD-SDI), but the encoder would do the same thing as 23.976 and 24.0 PsF. That is, weave the two fields into a progressive frame and then encode the video as 25 fps progressive.

From the HD-SDI point of view, sending 25p source as 25i or 25PsF is exactly the same thing. From the encoders point of view, 25i input gets coded as 25i and 25PsF input gets encoded as 25p.

Ron

+1

And another (though now obsolete) benefit or 23/24sF was CRT monitors. 23/24sF will look like 48i to an analog monitor and display normally albiet some minor flicker. 24P cannot be displayed by a CRT monitor unless it's specially designed including different phosphers. IOW, useless for TV work. The flicker was still deemed a problem by some production companies and they did not want to see it. So Evertz and Sony made low cost (by broadcast standards) 3/2 adder products that converted the signal to 59/60i for monitoring use.

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post #102 of 274 Old 08-17-2013, 12:46 PM
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Quote:
Originally Posted by Chronoptimist View Post

50i - there are 50 interlaced fields. 25i would be 12.5fps. (or 25fps at half resolution)

Use whatever notation you feel comfortable with. When I used "25i" in my previous post, it was shorthand for 25 interlaced frames per second. For me, I like to normalize everything to frames per second. That's how the bit-stream is signaled (in the MPEG2 sequence_header or H.264 SPS) and it also describes how much work the encoder has to do in pixels per second or macroblocks per second.

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post #103 of 274 Old 08-17-2013, 12:57 PM
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Originally Posted by Chronoptimist View Post

50i - there are 50 interlaced fields. 25i would be 12.5fps. (or 25fps at half resolution)

This is a very common industry problem. Especially once the computer industry (no offense to them intended) started getting into video and mis-applying the terminology.

However most people know there is no such thing as 12.5 or 15fps standard (in entertainment television systems) so we know it's really 50i or 60i which means 25 or 30fps.

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post #104 of 274 Old 08-17-2013, 02:36 PM
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Originally Posted by dr1394 View Post

Quote:
Originally Posted by Chronoptimist View Post

50i - there are 50 interlaced fields. 25i would be 12.5fps. (or 25fps at half resolution)

Use whatever notation you feel comfortable with. When I used "25i" in my previous post, it was shorthand for 25 interlaced frames per second. For me, I like to normalize everything to frames per second. That's how the bit-stream is signaled (in the MPEG2 sequence_header or H.264 SPS) and it also describes how much work the encoder has to do in pixels per second or macroblocks per second.

Ron
Ron, the problem with that is that is that the rest of the world counts the fields and not the frames. It's like saying that I prefer to think of circuits in terms of admittance so I'll describe my speakers in Mhos.
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post #105 of 274 Old 08-17-2013, 02:44 PM
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Originally Posted by olyteddy View Post

Ron, the problem with that is that is that the rest of the world counts the fields and not the frames. It's like saying that I prefer to think of circuits in terms of admittance so I'll describe my speakers in Mhos.

The EBU uses the notation 1080i/25.

http://tech.ebu.ch/docs/tech/tech3299.pdf

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post #106 of 274 Old 08-17-2013, 03:19 PM
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Originally Posted by dr1394 View Post

Quote:
Originally Posted by olyteddy View Post

Ron, the problem with that is that is that the rest of the world counts the fields and not the frames. It's like saying that I prefer to think of circuits in terms of admittance so I'll describe my speakers in Mhos.

The EBU uses the notation 1080i/25.

http://tech.ebu.ch/docs/tech/tech3299.pdf

Ron
I apologize for generalizing about the rest of the world. The document you cited is apparently European:
Quote:
Originally Posted by http://tech.ebu.ch/docs/tech/tech3299.pdf 
This document specifies the basic image formats and digital sampling systems for High Definition Television (HDTV) production in the European 50 Hz environment.
Living in the 60 Hz American environment I would still think it preferable to use the common nomenclature.
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post #107 of 274 Old 08-17-2013, 05:34 PM
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Originally Posted by dr1394 View Post

Quote:
Originally Posted by olyteddy View Post

Ron, the problem with that is that is that the rest of the world counts the fields and not the frames. It's like saying that I prefer to think of circuits in terms of admittance so I'll describe my speakers in Mhos.

The EBU uses the notation 1080i/25.

http://tech.ebu.ch/docs/tech/tech3299.pdf

Ron

 

Thanks for that link: Personally, I'm surprised at that.  For anyone quickly reading that pdf, it's charted well at the section "4. Nomenclatures and Image Sampling Systems".

 

It's not how I've ever seen it referred to here (USA).  It's usually without the slash over here, but in any case, the number trailing the format specifier is the field rate (aka Hz), not the frame rate.  Big resounding "huh".


Java developers, when I saw what has been placed into Java 8 I was immediately reminded of how I've spent so much of my life trying to protect engineers from themselves. Lambda expressions are a horrible idea. Gentlemen: the goal isn't to make code readable for a competent mid-level engineer. The goal is to make code readable for a competent mid-level engineer exhausted and hopped up on caffeine at 3 am. What a disaster Java 8 is!
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post #108 of 274 Old 08-17-2013, 09:31 PM
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Quote:
Originally Posted by dr1394 
When I used "25i" in my previous post...
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Originally Posted by dr1394 View Post

The EBU uses the notation 1080i/25.

http://tech.ebu.ch/docs/tech/tech3299.pdf

Ron
But the EBU very rarely write 25i. They're much more likely to write 50i than 25i (there are about 34x as many documents on ebu.ch containing 50i as ones with 25i according to Google).
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BBC TECHNICAL STANDARDS use of terms.
This document is a complete guide to the common technical standards agreed by the BBC, BSkyB, Channel 4, Channel 5, ITV and S4C.

Examples;

2.1 High Definition Format
All material delivered for UK HD TV transmission must be:
  • 1920 x 1080 pixels in an aspect ratio of 16:9
  • 25 frames per second (50 fields) interlaced - now known as 1080i/25.
  • colour sub-sampled at a ratio of 4:2:2

The HD format is fully specified in ITU-R BT.709-5 Part 2.

2.1.3 Film motion or ‘film effect’
  • It is not acceptable to shoot in 1080i/25 and add a film motion effect in post-production. Most High Definition cameras can capture in either 1080i/25 or 1080p/25. Where film motion is a requirement, progressive capture is the only acceptable method.


2.1.4 Field dominance
  • Cuts in material must happen on frame boundaries (i.e. between field 2 and field 1). Motion on psf material must always occur between field 2 and field 1 (i.e. field 1 dominance).

Note - It is possible to shoot material at 1080p/50. If this is done, the correct 2-frame marker phasing must be maintained when down-converting to 1080i/25 or 1080psf/25.

.
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post #110 of 274 Old 08-18-2013, 04:35 AM
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The point is, 25i is incorrect. 1080i/25 is the current preferred way of writing it according to the EBU/BBC but they also use 50i a lot. 50i is also correct as it's used in many EBU documents and by the BBC.

But they almost never use 25i.
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So which one of you arguers is going to move the original poster and his HT gear to England or Europe? As you can see, he is from the USA. It's nice that you can find all kinds of foreign documents that support your point but the fact remains that they are foreign to the topic.

Reminds me of the scene from Pulp Fiction...
"You know what they call a quarter pounder with cheese in Paris?" rolleyes.gif
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Originally Posted by olyteddy View Post

So which one of you arguers is going to move the original poster and his HT gear to England or Europe? As you can see, he is from the USA. It's nice that you can find all kinds of foreign documents that support your point but the fact remains that they are foreign to the topic.
The posts in question were about the topics raised in the thread, rather than directed specifically to the OP.
Also is it a requirement that all users alter their formatting to that used by the OP of a thread or their region even though the posts weren't specifically directed at the OP of the thread but were about the topics of the thread in general?
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Quote:
Originally Posted by olyteddy View Post

So which one of you arguers is going to move the original poster and his HT gear to England or Europe? As you can see, he is from the USA. It's nice that you can find all kinds of foreign documents that support your point but the fact remains that they are foreign to the topic.
The posts in question were about the topics raised in the thread, rather than directed specifically to the OP.
Also is it a requirement that all users alter their formatting to that used by the OP of a thread or their region even though the posts weren't specifically directed at the OP of the thread but were about the topics of the thread in general?

 

You didn't direct this to me, but I'll answer: There is no such requirement, IMO, you're right.  Any standard that is real is certainly perfectly fine to use, including this confusing one.  What I'd suggest however is to adopt the Hz (field) nomenclature, not the fps.  Otherwise you'll clash with the vast majority of everything I've ever read in relation to this topic.

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Once again it really doesn't make any practical difference. You hand any broadcast or production facility world wide a 25i labeled tape or file, they know it's really 50i. Same goes for 30i means 59i or 60i. And the playback device will often determine the frame and filed rate as well through metadata or by simply analyzing the signal in the case of intraframe compression like most broadcast tape format use.

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post #115 of 274 Old 08-19-2013, 11:24 AM
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Quote:
Originally Posted by Glimmie View Post

Once again it really doesn't make any practical difference. You hand any broadcast or production facility world wide a 25i labeled tape or file, they know it's really 50i. Same goes for 30i means 59i or 60i. And the playback device will often determine the frame and filed rate as well through metadata or by simply analyzing the signal in the case of intraframe compression like most broadcast tape format use.

 

It makes a great deal of difference, because this is a place for conversation (and whatever degree of learning that comes along with that) and having a formalism mean two potentially distinct things is problematic.  I don't care what someone handed a tape understands.  I want to know what the people here mean.


Java developers, when I saw what has been placed into Java 8 I was immediately reminded of how I've spent so much of my life trying to protect engineers from themselves. Lambda expressions are a horrible idea. Gentlemen: the goal isn't to make code readable for a competent mid-level engineer. The goal is to make code readable for a competent mid-level engineer exhausted and hopped up on caffeine at 3 am. What a disaster Java 8 is!
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post #116 of 274 Old 08-19-2013, 11:49 PM
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Quote:
Originally Posted by tgm1024 View Post

It makes a great deal of difference, because this is a place for conversation (and whatever degree of learning that comes along with that) and having a formalism mean two potentially distinct things is problematic.  I don't care what someone handed a tape understands.  I want to know what the people here mean.

In actual specifications, none of those notations are used because they're ambiguous. For example, in the Blu-Ray specification the table for 1920x1080 MPEG-2 looks like this.
Code:
horizontal_size_value  vertical_size_value  frame_rate_value  progressive_sequence

    1920,1440                 1080          29.97(30000/1001)           0

    1920,1440                 1080          25                          0

    1920,1440                 1080          24                          1

    1920,1440                 1080          23.976(24000/1001)          1

So we should be using 1920h1080v25f0p to be absolutely clear. wink.gif

Ron

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post #117 of 274 Old 08-20-2013, 11:34 AM
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Quote:
Originally Posted by dr1394 View Post

In actual specifications, none of those notations are used because they're ambiguous. For example, in the Blu-Ray specification the table for 1920x1080 MPEG-2 looks like this.
Code:
horizontal_size_value  vertical_size_value  frame_rate_value  progressive_sequence

    1920,1440                 1080          29.97(30000/1001)           0

    1920,1440                 1080          25                          0

    1920,1440                 1080          24                          1

    1920,1440                 1080          23.976(24000/1001)          1

So we should be using 1920h1080v25f0p to be absolutely clear. wink.gif

Ron
The public Blu-ray specs says "50-i" etc
http://www.blu-raydisc.com/en/Industry/Specifications/PublicSpecs.aspx
http://www.blu-raydisc.com/Assets/Downloadablefile/bdj_gem_application_definition-15496.pdf
From the specs linked above:
Quote:
1920x1080x59.94-i, 50-i (16:9)
Quote:
Originally Posted by dr1394 
For example, in the Blu-Ray specification the table for 1920x1080 MPEG-2 looks like this.
Code:

horizontal_size_value vertical_size_value frame_rate_value progressive_sequence

1920,1440 1080 29.97(30000/1001) 0
Why is the table for "1920x1080 MPEG-2" showing "1920,1440 by 1080". The public specs above say 1440 on Blu-ray is only for MPEG4/AVC or VC1 (ie. isn't the public specs saying 1440x1080 isn't allowed with mpeg2 on Blu-ray?).
Do you have a link to where you got the table from?

Here's a specification that mentions 50i:
http://pro-av.panasonic.net/en/sales_o/p2/ag-hpg10/hpg10_spec.html
Quote:
1080/60i, 1080/30p over 60i, 1080/24p over 60i,
1080/24pA over 60i, 1080/50i, 1080/25P over 50i
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post #118 of 274 Old 08-20-2013, 12:42 PM
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Oye.
 


Java developers, when I saw what has been placed into Java 8 I was immediately reminded of how I've spent so much of my life trying to protect engineers from themselves. Lambda expressions are a horrible idea. Gentlemen: the goal isn't to make code readable for a competent mid-level engineer. The goal is to make code readable for a competent mid-level engineer exhausted and hopped up on caffeine at 3 am. What a disaster Java 8 is!
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post #119 of 274 Old 08-22-2013, 07:34 AM
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Oye.
Do you mean "Oye como va" or "Oy vey"? Just kidding! @Joe Bloggs, I work in the video compression industry and have access to the Blu-ray specification. I assure you what I posted is correct.

Ron

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post #120 of 274 Old 08-22-2013, 08:14 AM
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Quote:
Originally Posted by dr1394 View Post

Do you mean "Oye como va" or "Oy vey"? Just kidding! @Joe Bloggs, I work in the video compression industry and have access to the Blu-ray specification. I assure you what I posted is correct.

Ron
So the whole table is about mpeg2 And 1440x1080 MPEG2 is part of the allowed specs on Blu-ray even though the public specs say it isn't?
But the table you quoted from isn't available online?

But what I said is also true. The public specs I linked to say "50-i" and other specs like the one linked say "50i". I don't know anyone else saying "1920h1080v25f0p" to describe 50i smile.gif.
Broadcasters/video tech comparies are much more likely to say 50i or 1080/50i or one of the others. But are unlikely to say "25i".

So surely it's better to use the normal, standardised forms - the ones in use by video/broadcast companies to describe what is happening instead of making up new forms that aren't standard?

I agree that if you are describing what is happening it terms of computer code and variables it would be useful to know what exact values are allowed or tables of allowed values or show what is happening in terms of code or pseudo-code, but this doesn't mean new non-standard format names (ones we make up) should be used instead of commonly used, standardised video standard naming conventions - unless maybe if it really does make things clearer for most people .
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