Why use 23.97fps for downloads.

[Shadowmistress]

Would probably be a good idea... but the player I've got now is only a few years old. I'd most likely wait for it to die before replacing it.

Who knows? By the time that happens there may be a new medium available that can hold more.

[daveoggy]

So let me get this straight in my head. People (nerds or not) are capturing 1080 59.94i HD (video not film sourced) at full resolution and frame rate, then applying IVTC and therefore throwing away genuinely unique fields before finally deinterlacing and encoding at 23.976fps?

What would be interesting to know is how are the studios themselves are distributing their content in the digital domain. For example what frame rate is used for the video iPod version of Desperate Housewives? Or if there are studios in the USA allowing their content to be downloaded for a price, what are the frame rates used there?

[mrswla]

Actually, if they just made dvd players that held 15-20 disks so you don't have to actually load and unload them, that would probably solve alot of problems.


(But then of course, I'd want 50-100)

They do!! http://www.google.com/search?hl=en&q=dvd+changer

[vitualis]

Give me PAL anyday

How true.

Regards.

[mgh]

Some simple calculations(pl correct me if i am wrong)
Only for movies encoded to either NTSC or PAL.
Original frame rate=24
NTSC frame rate =23.976=24 (approximation)
PAL frame rate =25=1.04x24 (approximation0
Ratio of PAL frame height to NTSC frame height=576/480=288/240=1.2
That means PAL carries 1.2*1.04=1.25 times more info (approximation)
Which in turn means that for same quality PAL needs higher kbps for the video.
BTW, I am in PAL country. DVDs have become abundantly available only recently. But whatever NTSC VCDs (vv few i admit) I have seen had much better quality than the PAL VCDs.
I am convinced that for movies alone 23.976 fps with pulldown enabled is the best option for NTSC. Probably the same reason prompts the manufacturers to make the DVDs in NTSC format instead of PAL in my country.
As I understand PAL analog TV broadcasts have about 33% more bandwidth-so the perception that PAL as a format is better is true.
But is it better to make DVDs in NTSC film format for movies only?

[edDV]

So let me get this straight in my head. People (nerds or not) are capturing 1080 59.94i HD (video not film sourced) at full resolution and frame rate, then applying IVTC and therefore throwing away genuinely unique fields before finally deinterlacing and encoding at 23.976fps?

I hope not.

For "NTSC" regions*, 1080i is 1920x1080 29.97 frames per second (59.94 fields per second). Proper terminology is 1080i29.97 or 1080i30 for short.

For HDTV 24 fps film is first transferred to 1080p24 data. For 1080i distribution tapes 1080p24 is run at 23.976 and telecined using the usual 2:3 field repeat to make 1080i29.97 video. In theory, IVTC could be applied to broadcasted movies to return to 1080p23.976 progressive framerate. Progressive HDTV sets and some progressive DVD players do IVTC in hardware when the 2:3 field sequence is detected.

But it is important to understand that HDTV sets (and projectors) rarely display at 23.976 frames per second. Frames are repeated in various sequences to create display framerates from 48-72 fps (60 fps typical)

Some computer folk/nerds/geeks/fools attempt IVTC for their own reasons. Usually this has nothing to do with DVD playback to progressive HDTV sets. The HDTV will do its own IVTC. Their reasons seem to be:

- Eliminate interlace artifacts when viewing the movie on a progressive computer monitor. This can also be done by using a deinterlacing viewer.
- Reduce data by 20% by removing repeated fields.
- Compress further using algorithms that require progressive frames (e.g. wmv, divx, xvid)

None of this should be done to original 1080i29.97 TV camera generated material.

What would be interesting to know is how are the studios themselves are distributing their content in the digital domain. For example what frame rate is used for the video iPod version of Desperate Housewives? Or if there are studios in the USA allowing their content to be downloaded for a price, what are the frame rates used there?

They can convert the 1080p24 masters to whatever they please. Careful choice or framerates and resolutions can make TV display awful if that is their goal.

* The "NTSC" term is used to indicate geographic region and legacy field rates. There is no NTSC encoding in DTV (HDTV or SDTV).

[edDV]

Some simple calculations(pl correct me if i am wrong)
Only for movies encoded to either NTSC or PAL.
Original frame rate=24
NTSC frame rate =23.976=24 (approximation)
PAL frame rate =25=1.04x24 (approximation0
Ratio of PAL frame height to NTSC frame height=576/480=288/240=1.2
That means PAL carries 1.2*1.04=1.25 times more info (approximation)
Which in turn means that for same quality PAL needs higher kbps for the video.

True for film source material only. For normal TV, PAL has 20% higher frame resolution, but 20% lower framerate (25 vs 30) so the "bandwidth" or datarate is a wash for PAL and NTSC.

BTW, I am in PAL country. DVDs have become abundantly available only recently. But whatever NTSC VCDs (vv few i admit) I have seen had much better quality than the PAL VCDs.
I am convinced that for movies alone 23.976 fps with pulldown enabled is the best option for NTSC. Probably the same reason prompts the manufacturers to make the DVDs in NTSC format instead of PAL in my country.

As I understand PAL analog TV broadcasts have about 33% more bandwidth-so the perception that PAL as a format is better is true.
But is it better to make DVDs in NTSC film format for movies only?

Assuming ~24 fps, tradeoff is frame resolution vs datarate. Holding datarate constant, higher frame resolution creates more compression artifacts.

In analog TV, framerate and vertical lines are fixed. Increasing bandwidth increases horizontal resolution capacity for either PAL or NTSC.

[daveoggy]

None of this should be done to original 1080i29.97 TV camera generated material.

And

They can convert the 1080p24 masters to whatever they please. Careful choice or framerates and resolutions can make TV display awful if that is their goal.

So are companies which have TV camera based material producing downloadable content with a frame rate of 29.97fps?

[edDV]

None of this should be done to original 1080i29.97 TV camera generated material.

And

They can convert the 1080p24 masters to whatever they please. Careful choice or framerates and resolutions can make TV display awful if that is their goal.

So are companies which have TV camera based material producing downloadable content with a frame rate of 29.97fps?

That is what they broadcast. That is the way broadcast and home DV video is acquired. Downloads are usually highly compressed wmv format.

[markc32]

23.976fps does allow for more bitrate and is only ever used for divx/xvid.

it is mastered on ntsc films.

However, lordsmurf - it is easy (with knowledge) to convert a film to 23.976 with xvid. The problem - as you so rightly say - is leechers. A 2hr film say should never be converted to 1 cd as so many inappropriately do without heavily compensating resolution.
to do a 2hr encode for xvid at dvd res should be 1.4Gb or so.
I have an mpeg4 player and i can put 3 HQ movies on a dvd-r with xvid - 5 if short enough.

it is useful as pesky kids do their level best to destry dvds and they are not even mine!!

ie. it is a great backup procedure but not for sharing as it - as you so rightly say - kills bandwidth!

I download plenty of isos and too many p2pers cause me grief on a fast download!

You cannot author at NTSC film with standard authoring packages. you need to look to scenarist or so to do that anyway!

[adam]

markc32 I've never heard of any DVD authoring package that can't author NTSCfilm DVDs. Even the cheapest (~$50) programs have this capability. If you've had problems doing this in the past make sure you have added the required pulldown flags first. If your encoder doesn't give you the option you can add them into the video stream using pulldown.exe.

[CaptainVideo]

Ulead DVD Workshop 2 can't seem to handle NTSCfilm. Everytime I try to author a DVD using NTSCfilm source with 3:2 pulldown it gives me a video file that runs at twice the framerate.

Maybe I'm doing something wrong, but I haven't been able to figure out. So with NTSCfilm source I just use TMPG DVD Author which has no problem with it.

[lordsmurf]

A number of consumer and semi-pro authoring packages cannot handle NTSCfilm. TDA is one of the few exceptions, does fine. DVDWS2 cannot.

[Mr2001]

DVD-lab has no problem making NTSC film DVDs. It'll even apply pulldown flags if you forgot to do it yourself.

[adam]

That's news to me lordsmurf. Can you name any others because I'm really not convinced. I'm pretty sure DVDWS2 is the exception, not TDA.

Maybe just PM me though, don't want to go too off topic. Either way.

[manono]

23.976fps does allow for more bitrate and is only ever used for divx/xvid.

Baloney. The bitrate is the same, no matter the framerate. I understand what you're saying, though. At 23.976fps you'll get better quality at the same bitrate (=filesize). 23.976fps is used for anything you want to use it for. For DVD you encode at 23.976fps and apply pulldown afterwards.

You cannot author at NTSC film with standard authoring packages. you need to look to scenarist or so to do that anyway!

Baloney. I haven't seen one yet that doesn't allow 23.976fps encoded video with pulldown applied to be authored. You can encode at any framerate between 19.98fps and 29.97fps and with the right pulldown applied, it's DVD compliant. But, I don't use anything from Ulead either. I'd say that if the authoring app requires 29.97fps encodes, it's a piece of junk, no matter what it costs.

[jimmalenko]

23.976fps does allow for more bitrate and is only ever used for divx/xvid.

Baloney. The bitrate is the same, no matter the framerate.

I *think* he meant that it allows for a better distribution of bitrate, since there's 6 less frames per second

[manono]

Yes, jimmalenko, I had edited it just as you posted.

[jimmalenko]

Yes, jimmalenko, I had edited it just as you posted.

No. 1 minute after I posted

[manono]

Let me put it this way then. I hadn't seen your post before I posted my edited version.

[lordsmurf]

I'd say that if the authoring app requires 29.97fps encodes, it's a piece of junk, no matter what it costs.

I disagree. Authoring software should be geared for it's intended audience. People like us should not have 23.976 source. That's film, and not traditional sources that most people will be using.

If you work with film, odds are you'd be working with Scenarist too.

Nobody here should have film. That was the entire point of this thread.

[Mr2001]

"People like us" have access to plenty of 23.976 video even if we didn't film it ourselves. Why should we have to buy a professional authoring package for thousands of dollars just to experiment with video we have on hand?

[lordsmurf]

The 23.976 footage you refer too probably should not have been 23.976 to being with. It's unfit for quality DVD work.

The only true 23.976 we tend to get is already on a DVD.

[Mr2001]

The only true 23.976 we tend to get is already on a DVD.

Exactly... a DVD is an easy place to get video for someone who's playing around with authoring, or making a compilation disc.

[lordsmurf]

You're being contentious again.
That's atypical video work for most users here.

[Mr2001]

It's so "atypical", in fact, that even Ulead DVD Workshop has an option to import video from a DVD. I doubt I'm the only person here who's ever reauthored something from a DVD.

[Shadowmistress]

Now boys, play nice or I'll just threadjack and start talking about Blue-ray discs!

[manono]

Hi-

I disagree. Authoring software should be geared for it's intended audience. People like us should not have 23.976 source. That's film, and not traditional sources that most people will be using.

And I disagree with your disagreement. The OP was asking about why 23.976fps AVI for downloads. I thought most of his post was nonsense anyway. Obviously, if the 23.976fps AVI encode was done correctly, 23.976fps is the correct framerate. It's just a short jump from there to encoding and authoring such material to DVD.

An authoring app is intended to take DVD compliant elementary streams and author for DVD. I repeat that if it can't take 23.976fps with pulldown and author it, it's a piece of junk. As prices come down for camcorders able to capture as progressive 24fps film, we'll see an increase in posts about authoring 24fps home camcorder footage for DVD.

Nobody here should have film.

What? Are you saying this site is only for DV enthusiasts or others dealing with interlaced material? If that's what you're saying, it's certainly news to me. Plenty of people here are posting about AVI to DVD and DVD to DVDR. Majority or not, there are a huge number of posts about material that was film sourced, AVI and MPEG-2.

From the site mission statement at the top of the home page:

What is this site about?
This site will help you to make your own VideoCDs, SVCDs or DVDs that can be played on your standalone DVD Player from video sources like DVD, Video, TV, DV, Cam or downloaded movie clips like DivX, MOV, RM, WMV and ASF.

Seems to include film sources.

[trooper11]

Well I dont use any normal TV episodes to put on dvd, but I do alot of anime sources, which are almost always 23.976, and i thought that was just the nature of anime broadcast/capture process from the japanese source.

so when i do make a dvd, i have to work with 23.976 almost all the time