Infoseite // HDTV standard, Pan & Scan and Clean Transfer Encoding



Frage von iEnno:


Hello cheap slashCAM community, I hope you can answer me my questions.

HDTV:
With the Introduction of HDTV has been dispensed with backward compatibility anyway. Why have not abolished the interlacing?
So it amazes me that it grabs the signal is not simply a kind of interlacing ID. Would you (do this as I imagine), but one could say for example, at 1080p, that are now only 25fps, but full frames, so it would have been approximately the same data rate as the 1080i.
Gibts nen reason why something like this was not taken into account? If I think too simple?

Pan & Scan:
I know that when letterboxing quasi through Clean encoding information in the black bars stuck to the image processing. This ensures that, given a 4:3-Television is no problem with a 16:9 television.
Pan & Scan, I can not imagine how the signal is transmitted backwards compatible. The only game that I would see would be stored in anamorphic signal, but the 4:3 picture would be completely distorted.
Where there's a 16:9 television get his information for the missing image content in the pan & scan process?

Clean Encoding:
Increasingly, I notice lately that there must be some kind of transmitter to switch between 16:9 and 4:3.
Is, for example, sees a trailer for any show in 16:9 and these s.end slowly blinded to black, we see sometimes in Aperture that is being switched to 4:3, since pulling up at the last moment the faces and the black disappear from the letterboxing bars. Thus, if advertising for a movie night today at 20:15 Clock made on Kabel1, one sees s.end such advertising display on 4:3, since it is now with "Married with Children" continues.
Why all?
From the perspective of a 16:9 TV but the trailer has the WSS signal. Thus the 16:9-Television "Ah know you're a 16:9 signal, I'm gonna go get the lines ausm Clean Encoding and prepare according to the Picture." If, however, now a 4:3-signal that WSS has not even known who seeks 16:9 Television synonymous not only after nem Clean Encoding and stop is simply there nen 4:3-Picture.
Why this apparent switch?


I trust me you can answer my questions;)

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Antwort von tommyb:

HDTV:
Interlacing is still a very big advantage: they can be 50 frames per second (as the fields with approximately 1920x540 pixels resolution), save (fluid movement) and still save space (50 progressive images were admittedly as a liquid and would look better, but would synonymous about twice as much space beanpruchen).

In short:
Picture 1080p50 = super duper but double memory consumption
1080p25 = super duper picture but no liquid image reproduction (see jerky image when panning through the football stadium)
1080i50 = fluid images, the same space as 1080p25, barely visible, inferior image quality in Comparison to 1080p50


Pan & Scan:
If he does that anyway? To my knowledge, is sent with a maximum of a 16:9 flag which says:

"Hey, this is 16:9! The Anamorphic Equalizer Picture and imagine it as correct. Oh yes, if you're a 4:3 television, then add the black bars above and below."

Pan & Scan again is something else: the 4:3 Television makes a Bildaussschnittsvergrößerung of the picture and fills the picture tube of from top to bottom. The aspect ratio remains the same (ie, people are represented not skinny or fat, circles are round and not oval), s.den sites, however, cut off the stupid picture.

Suppose we have 16:9 material, sooooo far left and the right two people are talking to themselves. The stupid 4:3 Pan & Scan Picture and Television magnifies the s.den sides, the two persons cut off (you can not see it). Even when we think would entertain some minds ...



Clean Encoding:
Although I have never heard of it, but so be it ...

What makes the Television is exactly what you have described. However, he does not turn around within nanoseconds between 4:3 and 16:9 display. Perhaps this is just synonymous s.der broadcasting technology that is used - perhaps the 16:9 / 4:3 switching signal is not always a Frame-accurate, possibly due to internal forces, the television programming by five frames to receive, and only if they all have the same 16 : have 9 or 4:3 signal, it switches around.

I can remember s.eine time VIVA. My Television has as crazy as that between 16:9 and 4:3 switch every few seconds. May well be that somewhere there was an interfering signal on the line, and the 16:9 signal was recorded again and again (for more than 5 frames). This has brought television to think: "Hey, 16:9! I need to switch!"

If he were to analyze instead of the five frames rather ten, then the fault might not just encountered.

Space


Antwort von iEnno:

First of thanks for the quick response!

Interlacing
Fluid movement is obvious. I've only ever stop clutching s.The 25Hz, the human eye will actually have a maximum, but it seems very well so nich hinzuhauen.

Pan & Scan:
Anamorphic images are not yet delivered. How will you teach old tube ner in retrospect that he should scale it properly and ask the Picture hinbacken top and bottom black bars?
Nen 16:9 picture but already is sent as letterboxing (if there is no pan and scan is, of course). Only that is sent to the PALplus halt halt nen WSS, creating a 16:9 television knows that stuck in the black stripe image information (= Clean Encoding), which he uses for image processing. So I've learned that at least ^ ^
The question that I asked myself now is, as a 16:9 Pan & Scan signal is sent. As is so synonymous again the problem of backward compatibility with older 4:3-Television of the problem. You have to prepare the signal so that the 4:3-Television can stop show. But recognizing the 16:9 television must s.irgendwas that it is just 16:9 and above all he has the missing image information herkriegen somewhere. And as that happens I ask myself stop.

Switching of 16:9 to 4:3 in a 4:3-Television:
As I said, yes, the 4:3 television has to do with switching of signals to nix. The can gar nich, because the 16:9 does not know. Accordingly, the transmitter switch must somehow happened. And I raff nich so right, do not see the sense.


These are the things, like the one I've learned. So, if something like this is wrong, please clarify for me;)

Space


Antwort von tommyb:

Quote: I've only ever stop clutching s.The 25Hz, the human eye will actually have a maximum, but it seems very well so nich hinzuhauen.
But this is true only for details. If we had a video with 1p, the eye would have a lot of time to be aware at the details. For 15p we would have much less time for it. So it is then synonymous with 25 frames per second and at 50 frames per second.

If a Picture is liquid or not, you can see very well. Otherwise we would not at all an 50 images have because we see no difference between 25 and 50th



Quote: Anamorphic images are not yet delivered.
Yes? Why then in the "switching" distorts the picture? Gripping times the Picture s.der antenna using a TV card s.and looking at you then to the material.


Quote: The can gar nich, because the 16:9 does not know.
When we speak here of the old black and white tubes of televisions or in the early 80s, then the statement is true. I have an old Trinitron Television - 16:9 and is the master of 1994. In addition, here is still around a device which is also tubular and is rather cheap brand. Date of manufacture is probably 1998th 16:9 is synonymous here, no problem.

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Antwort von iEnno:

"TommyB" wrote: If a Picture is liquid or not, you can see very well. Otherwise we would not at all an 50 images have because we see no difference between 25 and 50th
That is what I was so surprised half my life: D


Quote: Yes? Why then in the "switching" distorts the picture? Gripping times the Picture s.der antenna using a TV card s.and looking at you then to the material.
'm Sorry, no TV card and now grow only reason I would not, sorry. Did stop thinking, can someone explain to me with concentrated expertise;)
And the switching may occur - in my opinion - not at all synonymous of television, since the switch to 4:3 so TOO EARLY happening place with delay.


Quote: I have an old Trinitron Television - 16:9 and is the master of 1994.
Please Define "16:9 rule. Jetz nich know exactly what you mean. 16:9 without letterboxing or what? Then it's a 16:9 television. Logically, that dominated the 16:9;) I think you meant something else, right?


EDIT:
Perhaps I should mention that I still get analogue TV via cable. Digital TV will broadcast anamorphic I've just seen.

Space


Antwort von TheBubble:

"iEnno" wrote:
Nen 16:9 picture but already is sent as letterboxing (if there is no pan and scan is, of course).

This was formerly the case with an analog transmission, the current-day digital format can be anamorphic transfer and contain the correct aspect ratio, so that the correct representation.

"iEnno" wrote:
These are the things, like the one I've learned. So, if something like this is wrong, please clarify for me;)

Where did you learn this? Presumably this was received only on an analog transmission?

Without going respond individually to all questions to: Modern digital television to receive the program. These data include all information necessary for the presentation. In a normal analogue Übetragung can actually be so easily transmitted no anamorphic picture, in this case newer 16:9 TVs would only recognize that there is 4:3 in the audio signal above and below black bacteria and then enlarge the representation.

Space


Antwort von iEnno:

I've learned in my studies of the nem lecturer who nen few years has programmed graphics for character generators. But yes, most analog only.

We have now been resolved, although that is anamorphic 16:9 digital transfer, but still not my real questions.
I formulier times they re:

- How does a 16:9 television gets the missing image information from a pan and scan analog signal?

- Why do I see on my 4:3-Television with an analog television signal switching of 16:9 to 4:3? Is there any transmitter activated switch?

Space


Antwort von TheBubble:

"iEnno" wrote:
Like a 16:9 television gets the missing image information from a pan and scan analog signal?

Not at all.

"iEnno" wrote:
Why do I see on my 4:3-Television with an analog television signal switching of 16:9 to 4:3? Is there any transmitter activated switch?

Clearly yes, switch the radio station must, if he changes of widescreen to 4:3.

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Antwort von iEnno:

"TheBubble" wrote: Clearly yes, switch the radio station must, if he changes of widescreen to 4:3.
Good book now I just need to understand why ^ ^

Digital:
I was thinking this is resolved before the image processing that is in front of each picture halt ne type of digital ID, whether 16:9 or 4:3. Is not it so? Or will this identifier added only by the "switch"?

Analog:
As are indeed the black bars in 16:9 signal previously added. Ie, the 16:9 signal is through the black bars or less before the transfer 4-3. If now is a change of format, is a native 4:3-Picture. So why is there a switch necessary?


The only thing that makes sense now, in my view would be, that almost before the workflow is digital and therefore the signal is processed so far that it is ready to send before and still running in parallel with a D / A converter. So that the analog signal is generated only after the switch and I am on my 4:3 analog television therefore perceive the Formatumschalten.
But have the feeling that this is wrong xD

Space



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Antwort von Schleichmichel:

The ID is added by the sender, or is in the meta-information of the material.

And in the other case, "analog" is of course no switching necessary? I did not check how you come on it ...

Synonymous 16:9 I see on my screen when a 4:3-broadcast will be switched to 16:9, and vice versa synonymous. Genaus I see synonymous with some delay, a switch that if I toggle of one transmitter to another transmitter to send the different aspect ratios. What's the question?

Space


Antwort von TheBubble:

"iEnno" wrote:
Digital:
I was thinking this is resolved before the image processing that is in front of each picture halt ne type of digital ID, whether 16:9 or 4:3. Is not it so? Or will this identifier added only by the "switch"?

Anamorphic widescreen format, have a non-square pixel aspect ratio. This is therefore stored with, the digital receiver evaluates this out then. This works in principle similar to the DVD authoring s.PC at home.

Note: Even 4:3 digital broadcasts or synonymous, the popular DV - video are strictly anamorphic as horizontally with 720 pixels (or less) are working and therefore the pixels are not square.

"iEnno" wrote:
Analog:
As are indeed the black bars in 16:9 signal previously added. Ie, the 16:9 signal is through the black bars or less before the transfer 4-3. If now is a change of format, is a native 4:3-Picture. So why is there a switch necessary?


The "switch" may well be an automated process. If we are assuming that the transmitter prepared the material for a digital transmission exists, it must be the change of wide screen to the old 4:3 format for analog transmission, the scale changed (or off) before the A / D converter the actual analog signal generated.

The senderinterne workflow will always have at least sent s.höchstwertigsten oriented format.

Short-term apparent delay in the "switchover" could occur with a digital transmission if the bill is not exactly at the beginning of a new GOP (a group of frames, which are compressed together) will fall and the technology used does not automatically synonymous with the meantime, a new GOP start the correct aspect ratio can be (or, for completeness, the agreed upon format no arbitrary changes of the aspect ratio for each frame within a GOP synonymous allowed).

Space


Antwort von iEnno:

Thanks for the execution. Then I got on in spirit with my assumption, not so wrong location, that they will inherit the results of quasi-digital processing technology.


"TheBubble" wrote: Note: Even 4:3 digital broadcasts or synonymous, the popular DV - video are strictly anamorphic as horizontally with 720 pixels (or less) are working and therefore the pixels are not square.
Jetz, I'm confused.
I thought 720 * 576 square pixels are straight (DV). The pixels are still only through the distortion introduced by the television non-square, since it at 768 "pixels" are distorted (because less content presented on the same line width of 52¼s -> each pixel longer than normal -> gets wider / distorted) .
Please correct me if I'm wrong.

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Antwort von TheBubble:

"iEnno" wrote:
I thought 720 * 576 square pixels are straight (DV).

With a 4:3 aspect ratio resolutions are of 720x576 (PAL) or 720x480 (NTSC), as DV, do not square pixels.

If one were to accept the DV pixels rather than square, then the representation in the PAL version would be somewhat compressed in the horizontal direction.

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Antwort von WoWu:

@ iEnno

Quote: Why have not abolished the interlacing?
The question raised many, but of the 11 HD formats are currently defined 9 in progressive and interlaced, and only 2 in the target already provides for 1080p50.
It is therefore a matter of time that "interlaced" is history.

As far as the data rate between p25 and p50, they doubled, of course not, because procedures are not transferred to the GoP, the active image content, as in an I-frame method, but the error signal between the images, that is, the variances.
Because of p50 but the differences vary by the rapid sequence of images corresponding to low, it increases the transmission rate while, but not nearly doubled.
We have to do so by (i) with really only half the spatial Resolutionzu, but the fact synonymous with only half the transmission rate, at 50 p but not with the double transmission rate of 25p. 50p therefore much more efficient and is increasing bit rate, the only points at full spatial and temporal Resolutionan.
Quote: So it amazes me that it grabs the signal is not simply a kind of interlacing ID.
There is, yes, the flag heist "progressive: true / false", only that you have at 25 progressive images only every 40 ms a movement component at 50 ms half-pictures, but every 20 minutes. That one has only half the spatial resolution.
From 25p to 50i, so is not quite so simple, because they lack the additional time Resolutionim original material.
Quote: I know that when letterboxing quasi through Clean encoding information in the black bars stuck to the image processing. This ensures that, given a 4:3-Television is no problem with a 16:9 television.
The name "Clear Encoding" tells me, frankly, not synonymous and synonymous lies in the black bars, no additional image information. That was the case with PAL +. It was senderzeitig a 16:9 Picture of 576 lines scaled down to 432, so that was a 4:3 TVGerät (no PAL +) to show distortion.
In the black lines of a color difference signal of blue was added to transfer the remaining 2x72 lines. Additional color content were not transferred, but from the existing line interpolation.
The sharpness in the horizontal direction was for PAL broadcasts always (slightly) less than 5 MHz, corresponding to 560 horizontal pixels.
Pan & Scan, incidentally, as far as I know made no German channels ever, because this is the image editing each variable, a corresponding section through the scanner, according to the image content selected, for example, to cut off any heads.
Rather, it was selected most of a rigid 4:3 picture window and clipped the side content. So there is no pan & scan.

But to your Umschaltfrage:
There are several control signals, both digital-synonymous than for analog television.
Now it is but in your case as to how the signal you receive. For example, pure analog, from a terrestrial channel, which is synonymous analog supplies? -There is, I believe, in Germany, now no longer - or from a satellite receiver, and Dost were only to your analog TV?
If you're coming from the cable still will receive an analog signal, the data lines usually inserted only at the head station. This includes the synonymous 16:9 control, but it is synonymous VPS, etc.
So here we would have time to look closely to fully answer your question.
At any rate, expressed in the playout of the channel leading to a more None Today "16:9 button to signal the format.
Perhaps there are still some city stations ... is it possible, but today the flags are automatically read.

Another variation is even more that the broadcaster had not bought any rights of 16:9.
The broadcast, however, see synonymous for an obligation not to be allowed to cut off the credits. This means that the

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