HD and SD 3:2 Pulldown and 2:2 De-interlacing Tests. What do they mean?

[Panayotis Melas]

Hello, everyone.

This is my first posting here and I am glad doing it.

I found this forum in an Internet search, and as soon as I read a few posts, I immediately decided to become a member.

I have been a Home Theater aficionado for many years, but Blu-Ray was out of my reach. Actually, I was waiting to let the format mature and then take the step. Finally, I bought the Panasonic DMP-BD55 and I inititally set it up to my system, routing its HDMI output directly to my JVC DLA-RS2 input and its 7.1 analog output directly to my Denon AVC-A1SE 7.1 analog pre-input.

Unfortunately, I did not enjoyed it for much time, because I had to leave my home for professional reasons. I hope that next month I'll be home again.

Let me now place a series of questions for a matter, which was also one of my criteria to select this player.

Reading the various tests in the specializing magazines, of English or of Greek language, I found out that this player (as well as its smaller brother, the BD35) do not present any problems with the de-interlacing of the HD video material (perhaps also with the SD one), while others of the same generation do.

Although I was not sure whether this is critical or not, I chose the BD55 for this reason. In order to demonstrate what I have read, following are examples of the reviews I checked for four different models, including the BD55 and BD35. The reviews are from Home Theater Magazine, all four by Kris Deering:

A. Sony BDP-S350

.....I started my testing regimen with some HD material. The BDP-S350 is the only Sony player to date that properly deinterlaces film-based 1080i material to 1080p with a 3:2 cadence. There still isn’t a large amount of disc-based content out there that this applies to. However, it might become more of an issue as studios release pre-recorded film content at 1080i or make cable recordings onto blank disc media. The BDP-S350 does not properly deinterlace 1080i material with a 2:2 cadence. This applies to concert media or anything sourced from a 30-fps camera. A few concert videos on the market today (including some by Sony BMG) employ a 2:2 cadence.....

(http://hometheatermag.com/discplayer...lu-ray_player/)

B. Panasonic DMP-BD35 and DMP-BD55

....The DMP-BD35 and DMP-BD55 did a spectacular job in our video tests. These are the first Panasonic players that pass all of our video processing tests for deinterlacing.....
......Panasonic has included the ability to play back standard DVDs at 1080p/24, which is a rarity for Blu-ray players. For all the people with 1080p/24-capable displays, it’s a bonus to be able to take advantage of removing the judder that’s associated with 3:2 pulldown.....

(http://hometheatermag.com/discplayer...u-ray_players/)

C. Sony BDP-S5000ES

....The BDP-S350 (HT, November 2008) was Sony’s first Blu-ray player to include HD deinterlacing, although it was limited to 3:2-based material. Unfortunately, the BDP-S5000ES takes a step back in this department. With our standard 1080i HD deinterlacing tests, the BDP-S5000ES didn’t pass our 3:2- or 2:2-based deinterlacing tests. This is surprising at this price point, since there are a number of lower-end players that have no problems with these tests at all. There are only a few 1080i-encoded Blu-ray Discs out there, but it’s still important for a player to offer the right video processing to maximize video performance with all discs.....

(http://hometheatermag.com/discplayer...lu-ray_player/)

D. Samsung BD-P2500

.....As you can see from our video-processing test results, the BD-P2500 does an exceptional job with both HD and SD video processing. The inclusion of the Reon video-processing chip makes this a very capable player with outstanding deinterlacing and scaling performance, which allows superlative 1080p playback from DVD discs. Unfortunately, the BD-P2500 does not offer frame-rate conversion of DVD material like the recently reviewed Panasonic DMP-BD35 and DMP-BD55. Those players allow for 1080p/24 playback of DVD material. The BD-P2500 is limited to 1080p/60 on DVDs, which is typical of most Blu-ray players. This one simply does it better than most.



The HD decoder does have an issue with chroma upsampling with HD material mastered with a 2:2 cadence (not shown in our chart). This content represents a tiny segment of the market, but the player revealed obvious banding with our 2:2 Chroma Upsampling Error (CUE) test pattern. The player didn’t show any signs of chroma error with DVD material or the more common 3:2 cadence with HD material.....

(http://hometheatermag.com/discplayer...yer/index.html)

Therefore, my questions are:

1) What does exactly mean 3:2 and 2:2 pulldown, in simple words?

2) How is this process connected to de-interlacing? (I know what "de-interlacing" means)?

3) Why is this important for HD (or even SD) material?

4) Does this apply in all kinds of video signals and standards (i.e. ATSC, NTSC, PAL, etc.)?

Please, forgive my ignorance on this matter.

Thanks in advance.

[Trix]

Originally Posted by Panayotis Melas

Therefore, my questions are:

1) What does exactly mean 3:2 and 2:2 pulldown, in simple words?

2) How is this process connected to de-interlacing? (I know what "de-interlacing" means)?

3) Why is this important for HD (or even SD) material?

4) Does this apply in all kinds of video signals and standards (i.e. ATSC, NTSC, PAL, etc.)?

Please, forgive my ignorance on this matter.

Thanks in advance.

0) Welcome to the forums!

1) 3:2 pulldown is the process by which 24 frames per second material is decoded for display at 60 frames per second. In essence, the player, in this case, displays the frames is a 3:2 sequence; 1,1,1,2,2,3,3,3,4,4,5,5,5,6,6, etc. Thus, it "pulls-down" the 24fps material to adhere to 60fps standards. 2:2 pulldown is the same, but for 30fps material, such as digitally recorded programing. So, the player translates it as 1,1,2,2,3,3,4,4,5,5,6,6, etc., essentially doubling the framerate.

2) As far as it relates de de-interlacing, this is ususally just a process that has to be done in addition to de-interlacing when the source is, for example, 1080i30, as is typical of HD broadcast TV. So, the player performs both 2:2 pulldown and de-interlacing. (This is how I understand the concepts; please correct if I am way off.)

3) This is important as it is a measure of how well the players can handle different formats and frame rates. Most mainstreams BD's are encoded at 1080p at 24fps. So, 3:2 pulldown is crucial if one's TV must be fed a 60fps feed. Concert BD's are encoded at 1080i30, so it is crucial once again that the player properly convert it for display. Note that some sets will accept a 24fps input, meaning 3:2 pulldown is not as important. However, if the TV performs its own 3:2 pulldown, one must decide which device performs it better. Even for these sets, however, 1080i30 processing is required.

4) I'm not sure I have the paritculars to this answer, but in North America, this will apply to all discs formatted for the North American market. As far as PAL is concerned, for non-24fps material, they typically use a 50fps cadence, making the discs impossible to display on sets using a 60fps standard, with a few exceptions using multi-region players.

5) I hope you do get back to the Panasonic DMP-BD55, as I have the same player, and have loved it for the whole 3 days it has now been up and running.

6) I hope this answers most questions accurately, but I admit to having a somewhat limited knowledge base. So, please excuse me if anything is innacurate, but someone will be along to correct me shortly if this is the case.

Cheers!

[Anthony P]

1) What does exactly mean 3:2 and 2:2 pulldown, in simple words?

film is 24 frames (full pics) per second. in order to change it to 60i (for example to go over component) those 24 frames become 60 fields, so frames 1,2,3,4,5 becomes 1o,1e,1o,2e,2o,3e....... this is known as 3:2 because it has a 3:2 form (i.e. 1 is three times (1o,1e,1o) and 2 is two times (2e,2o)). since displays are progressive those interlaced frames need to be de interlaced. On the other hand that 108060i might not have come from 24p but from (for some HD cams and video) 30p, in that case to go from 30p to 60 i the correct way would be 1o,1e,2o,2e.... or 2:2. The issue is that in a way the player (or the display) getting 60i does not know where the video came from and might not combine the right fields together.

2) How is this process connected to de-interlacing? (I know what "de-interlacing" means)?

should be obvious

3) Why is this important for HD (or even SD) material?

well 2:2 could be a bit important since BD does not support p30, the studio could change so it would be 1080p24, but most likely it would have it as 1080p30 in a1080i60 envelope and so if it correctly de-interlaces it to P is important. Or the images created are not created correctly.

4) Does this apply in all kinds of video signals and standards (i.e. ATSC, NTSC, PAL, etc.)?

hard question 60Hz (60i) is the NTSC standard, Pal is built on 50hz (i.e. 50i) so 3:2 does not exist as much in it, but it has it's own issues (going from 24p to 25p or 50i). But if you use digital (like HDMI) it becomes a moot point since the TV will synch with the player and today displays are not built stuck to the old standards.

[4K2K]

Originally Posted by Anthony P

film is 24 frames (full pics) per second.

Most film but not all film.

hard question 60Hz (60i) is the NTSC standard, Pal is built on 50hz (i.e. 50i) so 3:2 does not exist as much in it, but it has it's own issues (going from 24p to 25p or 50i). But if you use digital (like HDMI) it becomes a moot point since the TV will synch with the player and today displays are not built stuck to the old standards.

But don't very few USA HDTVs support 50i/p inputs? But nearly all European HDTVs support 50i/p and 60i/p in SD & HD? Plus many (eg. those introduced in the last year or so) also support 24p inputs?

[welwynnick]

The thing with 3:2 and 2:2 pulldown is that it relates primarily to de-interlacing, and stepping back a moment, it is only one form of de-interlacing. The process is important when most sources are still interlaced (480i & 1080i) and most new displays are progressive.

But the de-interlacing process has to reflect the way the video was originally captured if it is to be most effective. Live TV is generally shot with interlaced digital video cameras, and is broadcast as such. Films are shot on film, which isn't captured by scanning, so is inherently progressive when mastered. The masters are interlaced for distribution (because that's what we've got, apart from 720p & Blu-ray), and since there's a frame rate difference, we have the telecine process that is described above.

3:2 pull-down is the inverse-telecine process that accomplishes both de-interlacing AND vertical refresh rate conversion. However, this is only applicable to US and Japanese video running at 60Hz that comes from film-sources. Inverse telecine simply recovers the original processive video that was interlaced for distribution. 3:2 is not used for video-sourced video like television (except where that is shot on film) and 2:2 is generally used in PAL and SECAM countries. Instead, TV has to use a different process because the original is interlaced, unlike film. Various processes are used, like bobbing, scaling and motion-adaptive.

De-interlacing is never perfect, and part of the problem is not simply the process of weaving the matching fields back together again, but in deciding whether or not to apply inverse telecine in the first place. Thats difficult, and if the de-interlacer applies video DI to film video by mistake, it will lose resolution. If it applies inverse telecine to television, you will get combing artifacts with motion, which is nasty. So for an I to P processor to pass the inverse telecine deinterlacing tests, it must be able to quickly and reliably detect what sort of video it is trying to de-interlace.

Since most blu-rays are 1080p24, this isn't an issue, and it happens that most BD players are poor at de-interlacing DVDs (though the newer Panasonics are good). What is a bit surprising is that the Sony flagship S5000 mentioned above has taken a backwards step with 1080i de-interlacing. Look a bit deeper though, and this might not be such a problem. The test is for 3:2 and 2:2 pulldown of 1080i video. Anybody see a hole in the reasoning?

Why would a BD player need to perform inverse telecine on 1080i video in the first place? If it's television video, then video DI is what's needed, not inverse telecine. If its video from a film, then it will be stored as 1080p24 on the disc, and 3:2 & 2:2 aren't needed! There are some obscure exceptions that only serve to prove the rule, but on the whole, nobody will ever notice.

Lack of good inverse telecine when playing DVDs however, will make a whole load of difference to everyone, all the time.

Nick

[4K2K]

Originally Posted by welwynnick

Since most blu-rays are 1080p24, this isn't an issue, and it happens that most BD players are poor at de-interlacing DVDs (though the newer Panasonics are good).

It's an issue when playing back every Blu-ray that isn't 1080p24 like documentaries and concerts and every Blu-ray with non-1080p24 extra features like behind the scenes documentaries or standard definition extras. Or up-scaling DVDs. Or playing back the movies that happen to be encoded 1080i50 instead of 24fps. European TV dramas recorded on film are also usually shot at 25fps so this would need to be encoded at 1080i50 if they don't slow the disc down and alter the audio pitch so those would need to be de-interlaced too.

Blu-ray advertises that they can upscale every DVD. If they can't de-interlace properly or upscale well that's not very good.

Ideally we could get rid of interlacing one day, especially for new content - and the studios would convert the interlaced content to progressive before putting it on disc - especially since some machines can't de-interlace properly. But until Blu-ray is capable of things like 1080p50 & 1080p60 I don't think we will be able to. It's a shame that Blu-ray is only capable of decoding progressive video at just one frame rate - 24 (1080p30 has to be encoded inside interlaced 1080i60). Hopefully that will change one day and we can totally get rid of interlacing.

[4K2K]

Originally Posted by welwynnick

Why would a BD player need to perform inverse telecine on 1080i video in the first place?

Because Blu-ray is not capable of natively encoding 1080p25 or 1080p30 or higher.
Because some 1080i50 or 1080i60 video contain progressive content, whereas other 1080i50 or 1080i60 video contains interlaced content. Most US TVs aren't compatible with 50Hz either so they often do yet another conversion.

Though when they encode 1080p30 into 1080i60 don't they flag it as progressive? If true, can't they just check for this flag? Are there any players that just check for this flag and/or detect it in other ways and display whether they think the current source is progressive or interlaced when reading 1080i encoded content?

[Anthony P]

Most film but not all film.

I don't know of any that is not, do you (curious to expand my knowledge of a movie on film that is not 24p)?
In the end I did not say all, and if it is most or all then it makes no difference to what I said. so take it as most if it makes you feal better. 3:2 applies to going from/to 60i/24p

But don't very few USA HDTVs support 50i/p inputs? But nearly all European HDTVs support 50i/p and 60i/p in SD & HD? Plus many (eg. those introduced in the last year or so) also support 24p inputs?

well the guy is in Europe (Greece) and I in Canada so who cares about the US as for the sets here, I think it depends, I have not done any research or kept data, but from the few displays I have seen, I would guess that in the higher and lower ends they tend to be more accepting while the middle range is less Though to be honest I am using my faulty memory and allowing pal/ntsc

Don't forget, in the end input is unimportant, if you feed the TV 50i and it is 60hz progressive. It needs to do some wicked processing to properly display it.

[4K2K]

Originally Posted by Anthony P

film is 24 frames (full pics) per second.

Originally Posted by 4K2K

Most film but not all film.

Originally Posted by Anthony P

I don't know of any that is not, do you (curious to expand my knowledge of a movie on film that is not 24p)?
In the end I did not say all, and if it is most or all then it makes no difference to what I said. so take it as most if it makes you feal better. 3:2 applies to going from/to 60i/24p

European TV dramas or documentaries that are shot on film are usually at 25fps instead of 24fps. I think there are some European films that are shot at 25fps to make them easier for TV distribution.

Wasn't "28 Days Later" shot mostly on PAL DV? (ie. 25fps/50hz) but I suppose they transferred it to 24fps.

Showscan films are 60fps.

Oklahoma! (1955) and Around the World in Eighty Days (1956) were shot twice. Once at 24fps and once at 30fps.

Animated films eg. Wallace & Gromit & Curse of the Ware Rabbit are sometimes shot at lower than 24fps. If animations are done on 2s there can be around 12.5-12 unique fps (eg. for intended 25-24fps).

Silent films were shot at different speeds. I think mostly shot below 24fps eg. (16fps-24fps) but I think projected around 18-24fps. Some were shot and projected higher than that I think eg. 26fps:
http://cinemaweb.com/silentfilm/bookshelf/18_kb_2.htm

Old newsreel type footage - shot on film - can be shot at different speeds too.

well the guy is in Europe (Greece) and I in Canada so who cares about the US as for the sets here, I think it depends, I have not done any research or kept data, but from the few displays I have seen, I would guess that in the higher and lower ends they tend to be more accepting while the middle range is less Though to be honest I am using my faulty memory and allowing pal/ntsc

Don't forget, in the end input is unimportant, if you feed the TV 50i and it is 60hz progressive. It needs to do some wicked processing to properly display it.

It's important ie. it would be better if all USA TVs could re-enable the 50Hz inputs because this would prevent the people doing the releases converting everything from 25p/50i/p to 24p/60i/p and either showing everything at the wrong speed and pitch/tempo like PAL film DVDs, or doing frame rate conversions that are not needed for the European market, which reduces the quality.

[sjy1969]

Just curious: Are these test failures due to inability of hardware to perform the tasks or can they be rectified by a firmware update?

Thank you.

[Panayotis Melas]

Thank you all, guys!

I really didn't expect that this thread would fire so many issues and create so much discussion. It seems that this is really something, that the various makers have to be careful of, when implementing a model.

I believe that in Europe, where PAL (and SECAM) are the TV standards, the 50Hz frequency can be easily adapted to 48, which is a multiple of 24. And roughly, there should not be any loss, therefore the 3:2 pulldown has no meaning in PAL/SECAM displays.

In fact, I have heard that the actual frame rate for a PAL DVD signal is not exactly 50Hz, but something lower, like a 49.xx Hz (I can't remember the exact number now).

Originally Posted by sjy1969

Just curious: Are these test failures due to inability of hardware to perform the tasks or can they be rectified by a firmware update?

Thank you.

I believe that these failures are mainly due to the incorrect programming of the player, but I also believe that the correct programming sometimes also depends on the hardware (chip or chips) that have to be capable for a correct programming.

Please, correct me, if I am wrong.

[4K2K]

Originally Posted by Panayotis Melas

I believe that in Europe, where PAL (and SECAM) are the TV standards, the 50Hz frequency can be easily adapted to 48, which is a multiple of 24. And roughly, there should not be any loss, therefore the 3:2 pulldown has no meaning in PAL/SECAM displays.

I think there are some displays that accept or display a 48hz signal, or display a 24p one at 48Hz, but most LCDs in Europe anyway are called 50Hz ones or 100Hz ones and I don't think they adapt to 48Hz. European displays labelled 100Hz can play back 60Hz content as well as 50Hz and often these days 24p too - so I guess (though am not totally sure) that they display 24p sources 5 times like their USA counterparts do. ie. they can operate at both frequencies (100Hz and 120Hz.). Insider Kjack said something like that I think, and he's the one who would know about this stuff.

therefore the 3:2 pulldown has no meaning in PAL/SECAM displays.

For European TVs with no support for '24p', European Blu-ray players like mine send feature film (24p) discs to the display at 60i/p. So such European HDTVs will need to remove that pull-down just like USA ones do. Plus playing back NTSC DVDs on European players/TVs that were filmed at 24fps but encoded at 60i with pull-down will also need pull-down removal. Lots of the extra features on Blu-ray titles are at NTSC resolution, even on the European version.

In fact, I have heard that the actual frame rate for a PAL DVD signal is not exactly 50Hz, but something lower, like a 49.xx Hz (I can't remember the exact number now).

I could be wrong but I thought that PAL signals were exactly 50Hz (someone please correct me if I'm wrong) and it was the NTSC signals that weren't exactly 60Hz. ie. NTSC is about 29.97 frames per second or 59.94 fields per second? and most, but not all 24 fps films are actually converted to/encoded as 23.976. This is to do with analogue NTSC and nowadays with digital I don't think it's really needed.

http://en.wikipedia.org/wiki/NTSC
http://en.wikipedia.org/wiki/PAL

[snowghost]

This is a great thread, but I'm still confused as to when 3:2 is introduced say on my Sony XBR LCD which is capable of 5:5 pulldown on 24fps BD and HD sources.

I played an SD of an old movie (The Dam Busters) on my Toshiba HD DVD player and forced the output to 1080p/24 which was recoginized as such by the TV. The movie looked normal with no jerky motion which I would have expected if you force 24fps on a 60hz source.

Can anybody explain what I'm missing here?

Thanks in advance.

[welwynnick]

Sounds like what is happening there is the Toshiba is performing inverse telecine de-interlacing on the 480i60 DVD video, and outputting it at the original 24 fps. Thats really 1:1 pulldown instead of 3:2 pulldown - every frame is reproduced once, not 3 or 2 times alternating. Then its scaled to 1080p resolution, which is quite clever because modern displays accept 1080p24 (but probably not 480p24). Thats quite clever, but its not anything that couldn't have been done before (it just wasn't).

The TV is then accepting 1080p24 and frame rate converting it up to 1080p120. It simply does that by repeating every frame 5 times - hence 5:5 pulldown (or perhaps more accurately, 5:5 pull-up, because the frame rate is increasing).

That will leave you with upscaled NTSC DVD without any judder, which is a great result. I wonder, if the TV claims 5:5, whether the TV could do all that itself if given a 480i60 input?

Nick

[snowghost]

Originally Posted by welwynnick

Sounds like what is happening there is the Toshiba is performing inverse telecine de-interlacing on the 480i60 DVD video, and outputting it at the original 24 fps. Thats really 1:1 pulldown instead of 3:2 pulldown - every frame is reproduced once, not 3 or 2 times alternating. Then its scaled to 1080p resolution, which is quite clever because modern displays accept 1080p24 (but probably not 480p24). Thats quite clever, but its not anything that couldn't have been done before (it just wasn't).

The TV is then accepting 1080p24 and frame rate converting it up to 1080p120. It simply does that by repeating every frame 5 times - hence 5:5 pulldown (or perhaps more accurately, 5:5 pull-up, because the frame rate is increasing).

That will leave you with upscaled NTSC DVD without any judder, which is a great result. I wonder, if the TV claims 5:5, whether the TV could do all that itself if given a 480i60 input?

Nick

Sony does advertise "reverse pulldown" for movie sources, so that probably is what you are referring to.

[Xorp]

Originally Posted by Anthony P

I don't know of any that is not, do you (curious to expand my knowledge of a movie on film that is not 24p)?

It's rare, but some European movies are shot at 25fps on film.