I don't understand the hype for 1080p/24 output

[Mintmaster]

The discussion covered also the question of how a native 24p ouput is better than a recovered 1080p ouput...i am not off topic.

A 1080p 24 output originated from an hd-dvd player playing a 1080i encoded disc wil still be 1080 24p output , it goes through the process i have exposed and its signal is worst in respect of another player with a movie encoded at 24p and outputting the 24p signal...

You don't need a 1080p/24 signalling standard to solve that issue. It has already been solved many years ago. Encode the disc in 24p. Even if you have a 1080p/24 signalling standard, it's not going to fix these 1080i encoded discs.

I don't even know what point your making here. Of course a 1080i encoded disc is worse than a 1080p/24 encoded disc. What does that have to do with 1080p/24 output?

does mentioning DVD means talking about the output in the first place...?

Yes, for the reasons above. Right here, you clearly illustrate that you know we're talking about output, yet insist "It doeas not change anything". A DVD player is not going to put out a non-standard pattern if it's encoded in 24p, nor do your compression issues have any impact (I see you've edited recently).

Even if the original info was 24p dvd, with no flags there is the risk of image degradation like i said before :

"It is also possible, but more difficult, to perform reverse telecine without prior knowledge of where each field of video lies in the 2-3 pulldown pattern. This is the task faced by most consumer equipment such as line doublers and personal video recorders. Ideally, only a single field needs to be identified, the rest following the pattern in lock-step. However, the 2-3 pulldown pattern does not necessarily remain consistent throughout an entire program. Edits performed on film material after it undergoes 2-3 pulldown can introduce "jumps" in the pattern if care is not taken to preserve the original frame sequence (this often happens during the editing of television shows and commercials in NTSC format). Most reverse telecine algorithms attempt to follow the 2-3 pattern using image analysis techniques, e.g. by searching for repeated fields."
http://en.wikipedia.org/wiki/Telecine#Reverse_telecine_.28a.k.a._IVTC.2Finverse_telecine.29

It's a process with a certain percentage of risk , errors , artifacts, in my opinion, 24p native will always be the better solution

Buddy, this was acknowledged after post #10. I have no issue with that, and 1080p/24 output will NOT solve that. These current 1080i MPEG2 streams will still not reach the TV in any better condition. You need a different stream. A DVD player has no reason to output a non-standard cadence with 24p encoded material.

What we have been arguing is your ranting about compression. That only applies to DV/HDV cameras trying to create a 24p look in a universally accepted 60i DV/MiniDV tape format, but you are talking about applying it everywhere. For shows and commercials in a DTV broadcast, 24p has been part of the standard since the beginning. That's not the issue here.



Here is the crux of my argument:

How the MPEG2 stream is encoded on the disc is all recording technology. I have no idea why anyone would encode a 24p source into a 60i stream on a DVD, HD-DVD, Bluray, or DTV. Moreover, if they did, 1080p/24 output on any player is not going to help.

By itself, 1080p/24 solves nothing. You need 1080p/24 media, and in those cases 1080i output is perfect. This is why the topic was started.

 

[shiggs]

Seems I am a little late to this party, but I thought I would add anyway (and probably repeat what others have already posted).

First, 24p input wont remove judder if the display is running at 60hz because extra frames will be inserted. The same goes for 60i input and 3:2 pulldown on progressive scan displays. To eliminate judder, you need to do reconstruct the 24p stream and display it at a multiple like 48, 72, 96 or 120.

Second, there are many display devices (mostly projectors) that can run at one of these 24p multiples (or 23.976 as it were). However, few if any will process an interlaced signal, IVTC and then display at a 24p multiple. Take the Sony "pearl" for example, in order to get 96hz you must feed it 24 or 48. So now you need a player that will output a 24p (or 48i) signal or video processor ($$$) that will.

Thrid, even the best video processors (HQV, ABT or Gennum) will have problems with some interlaced content, its a FACT. So besides saving a ton $$$, you save processing time which can introduce lip sync and of course visible artifacts that might occur from the deinterlacing process.

Fourth, some judder is inherent to 24p film camera and cannot be removed.

Sadly we are stuck with interlaced formats for a long time, at least for ATSC broadcasts, but hopefully display mfg's will step up and support [mostly] judder free playback.

 

[Ventresca]

You don't need a 1080p/24 signalling standard to solve that issue. It has already been solved many years ago. Encode the disc in 24p. Even if you have a 1080p/24 signalling standard, it's not going to fix these 1080i encoded discs.

This is just an example, we were are talking about why a native 24p signal is better then a recovered 24p signal, and i gave you an example of a sitation were it is.

I don't even know what point your making here. Of course a 1080i encoded disc is worse than a 1080p/24 encoded disc. What does that have to do with 1080p/24 output?

I am not making points to please you, or to please what in your head someone should say if is talking about the output.
But to answare you, i am talking about a process made by the player itself that will conditionate the output.

Yes, for the reasons above. Right here, you clearly illustrate that you know we're talking about output, yet insist "It doeas not change anything". A DVD player is not going to put out a non-standard pattern if it's encoded in 24p, nor do your compression issues have any impact (I see you've edited recently).

I am talking about a process that is done in camera, the output will came later, i dare to say that i think to know more than you what my head think, so i can assure you, here i am talking about the pulldown process itself and its ripercussion on a compressed video when the reverse telecine will be done, not about the output, this, like i said, will came later.

A dvd player can have a standard patter, but the TV can still make error when try to do the ITVC ,
so my point stand.

Buddy, this was acknowledged after post #10

For my prev post :

"It is also possible, but more difficult, to perform reverse telecine without prior knowledge of where each field of video lies in the 2-3 pulldown pattern. This is the task faced by most consumer equipment such as line doublers and personal video recorders."

You can state that the process goes 100% correct all the time, but in my experience, even with thousand dollars post production equipment, even with standard 3:2 pulldown pattern, the result is not 100% of the time perfect.

So no, the point was not alredy acknowledged.

I have no issue with that, and 1080p/24 output will NOT solve that.

with 1080p/24 there is no need of doing any reverse telecine, so there is no problem in the first place.

These current 1080i MPEG2 streams will still not reach the TV in any better condition.

Never said they would...i dont even understand what are you trying to say here...

You need a different stream. A DVD player has no reason to output a non-standard cadence with 24p encoded material.

Since you are making all this talk about 24p encooded dvd, i want you to pull a list of feature encoded at 24p, because i dont like to talk about air.
Also, like i said more than one time, even if the player output a perfect singal with no broken 3:2 pattern, the reverse telecine process is not 100% correct all the time.

What we have been arguing is your ranting about compression.

"we" ? "ranting" ?
Calm down

That only applies to DV/HDV cameras trying to create a 24p look in a universally accepted 60i DV/MiniDV tape format, but you are talking about applying it everywhere. For shows and commercials in a DTV broadcast, 24p has been part of the standard since the beginning. That's not the issue here.

This also applies to thousand of others compressed video formats (dvcpro,dvcpro50, dvcprohd,hdcam, ecc, ecc) not just for Dv/Hdv.
And this also applies for dvds encoded as 60i interlaced with flags inserted, then the player is set to recover the original 24p signal...wharever you like it or not, this process happnes before the singnal gets out of the player, it doeas happnes on an mpeg2 compressed stream.

Here is the crux of my argument:
How the MPEG2 stream is encoded on the disc is all recording technology.

And i am not talking about this, i am talking about what happnes when the player will process this material with its internal chips, in my example when a dvd player process a disc encoded as interlaced extacting the original 24p materail using the flags present in the mpeg2 stream, but you seems to not want to understand this.

I have no idea why anyone would encode a 24p source into a 60i stream on a DVD, HD-DVD, Bluray, or DTV. Moreover, if they did, 1080p/24 output on any player is not going to help.

A lot of dvds are encoded as interlaced with flags inserted for providing an evental pefect 24p recovered output, even if clealry the player will output it as 60fps signal to be compatible with the Tv.
This is the idea beyond this : begin able to offer a 60i output in the first place, for 100% compatibility with all the Tvs, and begin able to offer a progressive output for the Tvs that can handle it.

By itself, 1080p/24 solves nothing. You need 1080p/24 media, and in those cases 1080i output is perfect. This is why the topic was started.

If the reverse telecine process would be a perfect process without any risk of errors, then the 1080i output could be a perfect substitute of a native 24p output, but it is not.

1080p24 would also solve an huge problem for the europeans that would not get their movies speeded up to 25fps anymore, so, 1080p24 can solve more than nothing.

Bye,
Ventresca.

 

[Bohdy]

If the reverse telecine process would be a perfect process without any risk of errors, then the 1080i output could be a perfect substitute of a native 24p outout, but it is not.

You speak of it as if perfect pulldown and IVTC is rare. It's not. Most films originally recorded at 24p and transferred to DVD/HD use an uninterrupted standard pulldown pattern. This is very easy to detect after just a few frames by TV's with Inverse Telecine logic, and then you have the original 24p frames for the rest of the movie. It's that simple. There are exceptions, of course, but they are not the rule.

Edit:
Btw, I've tried to explain your apparent misconception about compression during Inverse Telecine before. Basically, it only happens when you are transferring video from one compressed format to another. Ie.

24p -> 3:2 Pulldown -> 60i Mpeg2 -> IVTC -> 24p Mpeg2
same for DV -> DV, etc.

That is the ONLY case where it applies. Are we agreed and understood?

 

[Ventresca]

You speak of it as if perfect pulldown and IVTC is rare. It's not.

Then why do you think a lot of movies store flags in the mpeg2 stream if it was so easy as you want to make it ?
Do you think the post studios do things just because they like to waste their time ?
I speak as i have experience of , how many movie have you seen in their native 24p form and in their recovered form, analized them side by side, and concluded "Its not" ?

I have seen many, and i always prefer the original 24p output.

Most films originally recorded at 24p and transferred to DVD/HD use an uninterrupted standard pulldown pattern. This is very easy to detect after just a few frames by TV's with Inverse Telecine logic, and then you have the original 24p frames for the rest of the movie. It's that simple. There are exceptions, of course, but they are not the rule.

It is not a "very easy" process, but, like the wiki link say, it is a "possible, but more difficult, to perform reverse telecine without prior knowledge"...but the point is, there is no garancy of having a "perfect" result all of the times, otherwise dvd posts would not waste time interting specific flags in the mpeg2 stream.

 

[Ventresca]

Edit:
Btw, I've tried to explain your apparent misconception about compression during Inverse Telecine before. Basically, it only happens when you are transferring video from one compressed format to another. Ie.

24p -> 3:2 Pulldown -> 60i Mpeg2 -> IVTC -> 24p Mpeg2
same for DV -> DV, etc.

That is the ONLY case where it applies. Are we agreed and understood?

It also apply when the dvd player process a disc encoded as interlaced , extacting the original 24p materail through the flags present in the mpeg2 stream, all of this happnes before the output, on the mpeg2 stream, a compressed stream.

We have 60i mpeg2 ->IVTC applyed on the mpeg2 stream with flags -> uncompressed output

Are we agreed and understood ?

Bye,
Ventresca.

 

[Bohdy]

It is clear you don't understand the purpose of the flags in an Mpeg-2 stream.

They are not used by the TV in the Inverse Telecine process. They are used by the DVD player to actially apply pulldown after decoding, to turn 24fps video into 30p/60i video for output.

It also applies when the dvd player process a disc encoded as interlaced , extacting the original 24p materail through the flags present in the mpeg2 stream, all of this happnes before the output, on the mpeg2 stream, a compressed stream.

We have 60i mpeg2 ->IVTC applyed on the mpeg2 stream with flags -> mpeg2 60p ->uncompressed output

No, that's not right. The video is not recompressed to Mpeg-2 (it doesn't need to be).

Assuming the source was encoded at 24fps, it goes:
Telecined film master -> 23.976fps Mpeg-2 -> Pulldown applied according to flags -> 59.94i uncompressed output -> IVTC -> 24fps display.

If a source already has pulldown before encoding (almost doesn't happen with retail movies) the there is still no recompression to be done; it just can't be recovered perfectly during IVTC.

 

[Ventresca]

It is clear you don't understand the purpose of the flags in an Mpeg-2 stream.

What i have said is that the flags are inserted so the dvd player can make a perfect 3:2 pulldown removal, please tell me where i am wrong.

They are not used by the TV in the Inverse Telecine process.

Clearly they are not, they can't because once the stream is uncompressed the flags are gone, this is what i am saying from 2 pages.

They are used by the DVD player to actially apply pulldown after decoding, to turn 24fps video into 30p/60i video for output.

Here is where you are wrong, completly wrong, the flags are use for removing the pulldown, for recovering the original 24p from the 60i source.

No, that's not right. The video is not recompressed to Mpeg-2 (it doesn't need to be).

It does not gets decompressed before the player apply the inverse telecine because of cost reasons.

Assuming the source was encoded at 24fps, it goes:
Telecined film master -> 23.976fps Mpeg-2 -> ????Pulldown applied according to flags ???-> 59.94i uncompressed output -> IVTC -> 24fps display.

If a source already has pulldown before encoding (almost doesn't happen with retail movies) the there is still no recompression to be done; it just can't be recovered perfectly during IVTC.

It is not the the 3:2 pulldown porcess that have need of the flags, it is the IVTC that use the flags to be able to remove the pulldown and recreate the original 24p from the 60i encoded disc, this is where you are wrong.

A lot of dvds are encoded as 60i dvd with flags, i dont know of any dvd encoded as 24p with flags...what you say would be a non sense, why including flags if the 24p stream is alredy here ?

Telecine -> 23.976fps digibeta-> 3:2 pulldown process -> mpeg2 60i with flags -> dvd player use the flags to recover the original 24p-> uncompressed otuput.

 

[Bohdy]

What i have said is that the flags are inserted so the dvd player can make a perfect 3:2 pulldown removal, please tell me where i am wrong.

Ok, so we are discussing two things; the DVD player performing the IVTC and producing 24p output, and secondly the TV performing the IVTC on 60i/30p input from the DVD player.

In the second case, the flags are only used by the DVD player to perform pulldown. IVTC is performed by the TV if it detects the pulldown pattern.
In the first case, the DVD player does look at the flags to determine if pulldown is being used and performs IVTC based on that.

Here is where you are wrong, it does not happens after the decoding, it does happens during the encoding process, because managing an uncompressed stream would requie a lot more powerfull and costly hw , than managing and converting the 60i mpeg2 stream to 60p and than uncompress the output.
...
It does not gets decompressed before the player apply the inverse telecine because of cost reasons.

What? Where did you get that nonsense from? The DVD player can and does do that with simple hardware logic.

Again, a lot of dvds are encoded as 60i dvd with flags, i dont know of any dvd encoded as 24p with flags...it would be a non sense, why including flags if the 24p stream is alredy here ?

It is necessary to meet the DVD specifications of 30fps output.

Here is a site: http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm explains it all, and shows you where you are mistaken.

MPEG-2 and DVD

So the basis of this technique is to restore proper timing by generating redundant image information from four film frames within every five NTSC video frames. But wouldn't it be silly to waste 20% of the storage space on every DVD with duplicate picture data?Fortunately the MPEG-2 standard nicely avoids this inefficiency. When a film source is encoded for presentation on DVD, it is stored at 24 frames per second; each video frame contains all the picture information from each film frame. There is no redundancy or duplication. Such a transfer is written to DVD as 720-pixel wide by 480-pixel high interlaced frames (where each frame contains two 720 by 240 fields), and there are only 24 frames for each second of film. This is known as 480i24. On each DVD encoded from a film source, a flag is inserted within the MPEG-2 data stream that instructs the player to repeat certain fields to reconstruct the 29.97 frame per second interlaced video. The player obliges by performing the 3:2 pulldown in real-time, continually creating interlaced frame sequences just like the one shown in the above figure, "The Telecine 3:2 Pulldown Process for NTSC Video."This capability enables the player to produce video compatible with conventional displays that were designed based on the NTSC video standard.(As we shall see later, progressive scan DVD players take a different approach.)

So the question really is what is the quality difference between IVTC performed on the player vs. IVTC performed on the TV. I'd say barely any on most movies.

 

[Ventresca]

double post

 

[Ventresca]

Ok, so we are discussing two things; the DVD player performing the IVTC and producing 24p output, and secondly the TV performing the IVTC on 60i/30p input from the DVD player.

For the imput ???
In the last 3 pages i always talked about the dvd player performing the IVTC and i have said to you lots of times , i dunno why this was so hard for you to get.

In the second case, the flags are only used by the DVD player to perform pulldown.

If a movie is alredy encoded as 60i...the payer does not have need to perform the pulldown, the pulldown was alredy done during the encoding.

IVTC is performed by the TV if it detects the pulldown pattern.
In the first case, the DVD player does look at the flags to determine if pulldown is being used and performs IVTC based on that.

The dvds are encoded as 60i interlaced, so the dvd MUST have to perform the IVTC in order to recover the 24p, THERE ARE NO 24P ENCODED DVD , how is this so hard to get ?
This is a quote from a forum i use to visit, from David Newman ,CTO, CineForm Inc.

For starters can't a DVD hold a 24p MPEG2 file?

No, the pulldown is rendered in so that a 24p source is encoded as 60i. There are no 24p encoded DVD, only 60i with 3:2 pulldown (or 25p within 50i.)
__________________
David Newman

http://dvinfo.net/conf/showthread.php?t=57007&page=2

What? Where did you get that nonsense from? The DVD player can and does do that with simple hardware logic.

wow...lol...whatever bro.

It is necessary to meet the DVD specifications of 30fps output.

Sorry, but you were talking about a 24 PROGRESSIVE ENCODED dvd, your site talk about a 24 frame INTERLACED ENCODED DVD.
Also, dvd encoded as 60i alredy meets the 30fps output specifications by theirself.

Here is a site: http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm explains it all, and shows you where you are mistaken.
So the question really is what is the quality difference between IVTC performed on the player vs. IVTC performed on the TV. I'd say barely any on most movies.

The difference, as i alredy explained many times, is that the player have the flags inside the mpeg2 stream to perforrm a perfect 3:2 pulldown removal, where the Tv , have not.

I think we are talking about a different kind of 'flags' , as i am talking about the specific informations inserted in the 60i dvds to perform a perfect 3:2 pulldown removal, this is not the same thing your are talking.


Bye,
Ventresca

 

[Mintmaster]

Vantresca, I don't know if you need to improve your english, but you're making no sense here.

As Bohdy already told you, Wikipedia supports our point of 24p encodings:

DVDs, however, are capable of storing the native 24p frames. Every Hollywood movie is laid to disc as a 24p (actually 23.796p - see below) stream.

Why do you keep going back to 1080i mpeg2 streams? How will 1080p/24 do anything to a 1080i stream? It has already been encoded, and it already has the artifacts you mention. If a DVD player can reconstruct 24p frames, it can also output a perfect standardized telecine pattern in 60i without interruption.

A 1080p/24 signal to the TV solves nothing. You understand? That is our point. Period.

This is just an example, we were are talking about why a native 24p signal is better then a recovered 24p signal, and i gave you an example of a sitation were it is.

No, your example tells us why a native 24p encoding is better than a 60i encoding of a 24p source. The signalling standard of 1080p/24, which this thread is about, has nothing to do with this.

I am talking about a process that is done in camera, the output will came later, i dare to say that i think to know more than you what my head think, so i can assure you, here i am talking about the pulldown process itself and its ripercussion on a compressed video when the reverse telecine will be done, not about the output, this, like i said, will came later.

Read again. Bob said the encoding is progressive. You replied by saying it doesn't matter, and artifacts will still occur. That is wrong. There is no compressed 1080i mpeg2 stream here at all.

A dvd player can have a standard patter, but the TV can still make error when try to do the ITVC ,
so my point stand.

How? Any talk about the TV making mistakes is related to non-standard or discontinuous patterns. You have other suggestions? A DVD player will output one pattern only if the encoding is 24p (unless someone did something stupid). The TV will lock onto that pattern and it will never flinch unless it thinks the cadence has changed. Just give me a reason why this wouldn't be the case.

I've never seen any problem with inverse telecine on standard cadence. Show me some evidence somewhere of this, and I'll believe you.

 

[Dave Baumann]

If DVD's weren't coded in such a fashion both ATI and NVIDIA wasted a heck of a bunch of hardware and development coding in support for such methods!

 

[Ventresca]

Vantresca, I don't know if you need to improve your english, but you're making no sense here.

The only nonsense here is the one you try to make on purpose.

As Bohdy already told you, Wikipedia supports our point of 24p encodings:

wow...the internet never stop to amaze me...some people are just crazy...do you know who David Newman is ? Do you know what cineform do in the industry ?
I consider him a bit more informed than a general wikipedia quote.
If you go to the link i posted, he also explain why some sites talk about the 24p encoding :

Sorry, I do know this one. The MPEG2 does has progressive modes, yet these are not support in today's DVDs. Pick a copy of DVD Demystified. 24p is encoding as 60i with repeat flags.

Why do you keep going back to 1080i mpeg2 streams? How will 1080p/24 do anything to a 1080i stream? It has already been encoded, and it already has the artifacts you mention. If a DVD player can reconstruct 24p frames, it can also output a perfect standardized telecine pattern in 60i without interruption.

Clearly 1080p/24 is not going to do anything for 1080i streams, i was just comparing them, but this seems too hard for you to understand...i guess , after all this pages , it is done on purpose to trash the discussion, or you have serious problems.

A 1080p/24 signal to the TV solves nothing. You understand? That is our point. Period.

The problem is, i never said otherwise...do you understand ? You can't stop to try to put word in my mouth can you ? it doess not contribute to make your point stronger..it just make you really annoying.

No, your example tells us why a native 24p encoding is better than a 60i encoding of a 24p source. The signalling standard of 1080p/24, which this thread is about, has nothing to do with this.

My example tell you that is false that you can always recover a perfect 24p signal from a 1080i output...here is the magic word you like.

Read again. Bob said the encoding is progressive.

Read again my quote, there are NO ENCODED 24P DVD...why it is so hard for you to get ?
Yes, Bob said progressive, but his link talk about INTERLACED 24i dvd, not progressive 24p dvd.

You replied by saying it doesn't matter, and artifacts will still occur. That is wrong. There is no compressed 1080i mpeg2 stream here at all.

I know what i replyed thanks, and i alredy explained very well why the IVTC can introduce artifacts without knowing the data first, this have nothing to do with the compression, sicne the signal is uncompressed.
Also, i remember i alredy clarified he was right when he said that if the IVTC is done on the uncompressed stream there is no loss on quality, but still , artifacts can came by the process itself going wrong.

How? Any talk about the TV making mistakes is related to non-standard or discontinuous patterns. You have other suggestions? A DVD player will output one pattern only if the encoding is 24p (unless someone did something stupid). The TV will lock onto that pattern and it will never flinch unless it thinks the cadence has changed. Just give me a reason why this wouldn't be the case.
I've never seen any problem with inverse telecine on standard cadence. Show me some evidence somewhere of this, and I'll believe you.

I think i have alredy explained this too much, its clear you have no movie post production experience, i have no time to waste to repeat the same thing again, again and again, belave what you want to beleave, love and peace !

Bye,
Ventresca.

 

[Bohdy]

The fact is that NTSC film DVD's are encoded in progressive (or interlaced, it doesn't matter as long as all pairs of fields match) 24fps mode, but with RFF and TFF flags inserted so that the decoded output is 60i unless the player recognizes the pattern of the flags and outputs progressive 24p again. That's the way it is. Check this page http://raph.levien.com/pulldown.html and the associated links for even more corroboration of this fact. You are just wrong.

Also, I don't mean this as an insult since it's not your fault, but you seem to have a lot of trouble with English, both in the writing and understanding, which is what has dragged out the debate.

 

[Mintmaster]

(NOTE: I am replying to your original response. You seemed to have significantly changed it. That is very poor forum etiquette.)

You are making no sense to me too.

Given that Bohdy, me, Gubbi, zeckensack, and others all understand each other, I'd say you're the odd one out.

I consider David Newman a bit more informed than wikipedia.

Right. So every DVD is encoded in 60i? Hollywood decided to ignore the fact that they're wasting 17% of the disc space? They're encoding at 17% lower bitrate for no reason? Everyone else is wrong? I don't care if he's CTO of CineForm, give me a break.

Cleraly 1080p/24 is not going to do anything for 1080i stream, i was just comparing them.

The problem is, i never said othervise...do you understand ?

My example tell you that is false that you can always recover a perfect 24p signal from a 1080i source.

Why were you comparing them? The example is useless. Of course I agree with it, but it's irrelevant.

If you never said otherwise, then what was the point of your 3 pages of posting? That's all Bohdy, me, and others are saying. We don't need a new signal to the TV.

Read again my quote, there are NO ENCODED 24P DVD, what wiki say is a just plain wrong.
Yes, Bob say progressive, but his link talk about INTERLACED 24i dvd, not progressive.

They're effectively the same thing. Combine fields and you have progressive. Perfect reconstruction. The question is how do you get this to the TV. Whether your signal is 1080i or 1080p/24 won't matter as long as the DVD outputs an unwavering standard pattern.

I know what i replyed, and i alredy explained very well why the IVTC can introduce artifacts without knowing the data first.

No you didn't. All you talked about was compression artifacts in a 60i stream (which none of us except you are talking about), and how it's hard to detect non-standard cadence.

Maybe you have some reading comprension problems...but it is stated here clearly in the wiki link this is not a easy process :

"It is also possible, but more difficult, to perform reverse telecine without prior knowledge of where each field of video lies in the 2-3 pulldown pattern. This is the task faced by most consumer equipment such as line doublers and personal video recorders. ."
http://en.wikipedia.org/wiki/Telecin... _telecine.29

They're talking about non-standard cadence. Hence the "without prior knowledge".

Also, again, 24p dvd does not exists, are out of the mpeg2 specificaions.

Irrelevant. Interlaced and progressive are interchangable at equal field rates.

 

[Ventresca]

If pulldown is "rendered in" before encoding as Dave Newman says, then it would be impossible to reconstruct all the original frames, no matter what, because of the intra-frame encoding of Mpeg-2 that was mentioned earlier.

Impossible ? I use to do this dealing with mpeg2hd and using the advanced pulldown i can extract the 24p and the result is perfect, it work the same way it do for Dv, that is an intraframe compression too.

"The 24p Advanced isn't intended for making the 60i video look like film; it's designed to allow the best possible recovery of the original 24 frames.
http://www.adamwilt.com/24p/index.html#24pRecording

He doeas not say it is rendered before the encoding, it say "is rendered in so that a 24p source is encoded as 60i." .
Generally the 3:2 pulldown is inserted by the mpeg2 encoder that take the uncompressed 24p stream from the digibeta tape (the telecined 24p master) and apply on the fly the 3:2 pulldown when encoding the mpeg2 video as 60i , this is what happnes the most part of the time and what David means.
Every Mpeg2 hw encoder can apply the 3:2 pulldown on the fly and store the video as 60i.

I think we are just misunderstanding him.

his quote is so clear there is no risk of misunderstanding i think.
"a 24p source is encoded as 60i. There are no 24p encoded DVD, only 60i with 3:2 pulldown (or 25p within 50i.)"

The fact is that NTSC film DVD's are encoded in progressive (or interlaced, it doesn't matter as long as all pairs of fields match) 24fps mode, but with RFF and TFF flags inserted so that the decoded output is 60i unless the player recognizes the pattern of the flags and outputs progressive 24p again. That's the way it is. Check this page http://raph.levien.com/pulldown.html and the associated links for even more corroboration of this fact. You are just wrong.

EDIT :
It does matter because it make your point very different, in your original post, you stated that all dvd were encoded with as progressive , storing a 24p mpeg2 stream on the disc, not an interlaced stream with flags, but a pure 24p stream , and then the dvd player would apply the 3:2 pulldown creating the 60i ouput...

You can't negate this because this is also what the wiki link say :

"DVDs, however, are capable of storing the native 24p frames. Every Hollywood movie is laid to disc as a 24p (actually 23.796p - see below) stream. With a progressive-scan DVD player and a progressive display, such as an HDTV, only the progressive frames are displayed and there is no conversion to an interlaced format -- eliminating the appearance of any interlace or de-interlacing artifacts. When displayed on a standard NTSC TV (which only display 60i) the DVD player will add 2:3 pulldown to the signal."

This is clearly the source of your misconception, and our disagreement.

I think hte david's statement is very clear :

"There are no 24p encoded DVD, only 60i with 3:2 pulldown"

And he also add that what wiki say is something not implemented on current dvds.

At this point, i have nothing more to add at the discussion...i alredy proved right what i needed to.

Bye,
Ventresca.

 

[Mintmaster]

Notice David Newman said "repeat flags". It is indeed only 48 interlaced fields of data per second in the stream. If a player is outputting 60i, the remaining fields are duplicated by the player as directed by these repeat flags.

That's exactly the misunderstanding that Bohdy is talking about.

Since you can't understand either of us or even David Newman, I'm not going to waste my time anymore. Work on your english first and ask questions if you're unsure of what we're saying.

 

[Ventresca]

(NOTE: I am replying to your original response. You seemed to have completely changed it. That is very poor forum etiquette.)

wow you are smart...you can call me impressed.

Given that Bohdy, me, Gubbi, zeckensack, and others all understand each other, I'd say you're the odd one out.

You are the only one making fuss on purporse.

Right. So every DVD is encoded in 60i? Hollywood decided to ignore the fact that they're wasting 17% of the disc space? They're encoding at 17% lower bitrate for no reason? Everyone else is wrong? I don't care if he's CTO of CineForm, give me a break.

Wow, sorry to breack it to you, but there are no 24p encoded dvd, there are no dvd with a pure 24p stream, get over it, no matter how much you moan.

I am part of the "Hollywood" and dont worry i am not ingroring what you are saying...but, fact is, there are no 24p encoded dvd, deal with it.

The only mention about 24fps to save space dvd is a 24i , INTERLACED encoding , and no, is not the same as saying that all the dvd store a 24p mpeg2 stream.

Also, from the first result i get from your googling...

"To date, all of my projects have been delivered on 60i DVD"
http://66.102.7.104/search?q=cache:...ollywood+dvd+60i+24p&hl=en&gl=us&ct=clnk&cd=1

If you go to the link, this user ask about the 24p delivery ?

I can make an internet page saying i can do 100fps encoding on dvd and it will play without any problem, it will make it true right ?

I gave you a professional source , not some random anonimous forums poster...if you want to discredit David Newman, you should do the same.

His quote is pretty clear...THERE ARE NO 24P ENCODED DVD, get over it.

Why were you comparing them? The example is useless. Of course I agree with it, but it's irrelevant.

I alredy said why, if for you is irrilevant, why do you pay so much attention to it ?

If you never said otherwise, then what was the point of your 3 pages of posting? That's all Bohdy, me, and others are saying. We don't need a new signal to the TV.

The point is the same made by democoder and londonboy...having a native 24p signal from a purist point of view, is better, end of the story.

A lot of people want a 24p standard, for a lots of reasons, even if you and Bohdy does not.

Also, a 24p standard would solve the problems for the auropeans getting their movies speeded up.

They're effectively the same thing. Combine fields and you have progressive. Perfect reconstruction.

No it is not the same thing, what he meant was storing on the dvd a pure 24p mpeg2 stream , and this is not possible, get over it.

The question is how do you get this to the TV. Whether your signal is 1080i or 1080p/24 won't matter as long as the DVD outputs an unwavering standard pattern.
No you didn't. All you talked about was compression artifacts in a 60i stream (which none of us except you are talking about), and how it's hard to detect non-standard cadence.
They're talking about non-standard cadence. Hence the "without prior knowledge".
Irrelevant. Interlaced and progressive are interchangable at equal field rates.

Alredy addressed and discussed.

Bye,
Ventresca.

 

[Ventresca]

Notice David Newman said "repeat flags". It is indeed only 48 interlaced fields of data per second in the stream. If a player is outputting 60i, the remaining fields are duplicated by the player as directed by these repeat flags.

The repeated flags are the one introduced with the 3:2 pulldown process, i perfeclty know what he say, and my point (no 24p dvd encoding) still stand.

That's exactly the misunderstanding that Bohdy is talking about.

So in your mind "repeated flags = yes all hollywood dvd are encoded as 24p mpeg2 streams " ?
I guess it also means it is impossible to reconstruct the original 24p frame with a if the pulldown is done during the encoding ?

If pulldown is "rendered in" before encoding as Dave Newman says, then it would be impossible to reconstruct all the original frames, no matter what, because of the intra-frame encoding of Mpeg-2 that was mentioned earlier.

This is were we disagree , i do this with mpeg2 so its not impossible.

Since you can't understand either of us or even David Newman, I'm not going to waste my time anymore. Work on your english first and ask questions if you're unsure of what we're saying.

You really can't get over the fact that you are wrong about 24p dvd encoding dont you ?

There is no point in trying to use my english as an excuse if you are making stuff up on what David said.

Bye,
Ventresca.