Compressor: Why is there a Progressive setting if DVD is interlaced?

[Mark Spano]

[Ralph Parker] “I’ve read posts in the Forums about using Compressor to take my sequences to Progressive, and then encode to SD m2v as a separate step. This confuses me”

It should. This is stupid advice. If you have an interlaced cut, you keep it interlaced. If you have a progressive cut, you keep it progressive.

[Ralph Parker] “there is a popup to choose Field Dominance which includes a Progressive setting; but if this is for SD DVD, why?”

You can make a progressive DVD if your cut is progressive. That usually happens when you’re cutting 23.976P. Most motion pictures on DVD are 23.976P encoded – it actually looks better since you can take the fixed amount of bits and spread them across fewer frames.

The simplest way I can explain Compressor’s encoding controls is this: whatever your cut is, keep it that way unless you are forced to change it. For example, if your cut is 1080i/29.97, and you want to go to SD DVD, keep interlacing. If you set that value to the “automatic” setting, Compressor will understand what you’re trying to do. Then, the only thing that you are ‘forced’ to change is the resolution. If you are compressing for MPEG-2 for DVD, then it’s 720×480/16:9 pixel aspect ratio.

In Compressor, the Frame Controls tab allows you to finesse the settings. For your compression, I would turn Frame Controls ON, set Resize to BEST, Leave deinterlacing alone (same as source/Fast), leave retiming alone (fast). This tells Compressor to spend some time doing the best it can in resizing your HD to SD 4×3 anamorphic.

Only adjust settings if you are forced to change them. In this case, the only thing you’re forced to change is resolution (frame size). Everything else should go through with as little compression artifact as possible.

[Ralph Parker]

Thank you, Mark, for your detailed reply.

[Mark Spano] “You can make a progressive DVD if your cut is progressive”
If the DVD standard is indeed interlaced, when you say you can make a progressive DVD, does the m2V encoding do some sleight of hand to make progressive frames into interlaced?
If I were to convert the project sequences to progressive, (for learning’s sake), by using the mentioned settings, would that give my video a softer “film look” as opposed to the harsh, stark video look?

Ralph Parker
2×2.4 Quad Core Xeon, 8GB
Final Cut Pro 7, Motion 4, Etc.

[Mark Spano]

[Ralph Parker] “does the m2V encoding do some sleight of hand to make progressive frames into interlaced?”

Yes, specifically this (from Wikipedia):

By using a pattern of REPEAT_FIRST_FIELD flags on the headers of encoded pictures, pictures can be displayed for either two or three fields and almost any picture display rate (minimum ⅔ of the frame rate) can be achieved. This is most often used to display 23.976 (approximately film rate) video on NTSC.

[Ralph Parker] “If I were to convert the project sequences to progressive, (for learning’s sake), by using the mentioned settings, would that give my video a softer “film look” as opposed to the harsh, stark video look?”

That I don’t know – you might have to experiment. I would do any of that type of experimentation in Compressor rather than FCP. If you set a sequence to progressive in FCP, I believe it will just throw away a field. Compressor offers the options (especially within the Frame Controls tab – Retiming) to smooth the motion between frames when retiming footage. It’s worth trying small sections to see if it’s a look you like. Also of note for this type of conversion is the great and useful JES Deinterlacer app. Check that out – the instructions are pretty detailed and informative. After those, there are various filter packages you can buy for FCP that do retiming with varying degrees of sophistication.

[Jeff Greenberg]

Yes, all DVDs are interlaced – they can store 23.976 information as progressive (if it’s progressive) and then add pulldown to become 30i.

[Ralph Parker] “If I were to convert the project sequences to progressive, (for learning’s sake), by using the mentioned settings, would that give my video a softer “film look” as opposed to the harsh, stark video look?”

Yeah, um. No.

You want a film look? Shoot film.
Film ‘looks’ are 3 things:
Frame rate, short Depth of Field, S curve color correction.

You’ll do better to:
Get Magic bullet or other sort of ‘filmic’ response.
If you didn’t shoot with a good looking DOF, try to build it.
Not worry about interlacing/24- The 24p look is the least of the three to ‘feel’ filmic.

Best,

Jeff G

Apple Master Trainer | Avid Cert. Instructor DS/MC | Adobe Cert. Instructor
————
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[Scott Smith]

Disclaimer: It is possible that I may be confused, or behind a software version.

BUT, if you are using Final Cut Pro and Compressor, it would also stand to reason you will use DVD Studio Pro. In DVDSP, you can make an HD DVD project progressive scan, but the SD DVD projects are all interlaced. So if you are making a Standard Def DVD in DVDSP, it will be interlaced.

What I don’t know is if you start with progressive, transcode to MPEG2 progressive, then make a SD DVD in DVDSP, what happens to the progressive scan’s extra lines, as it makes it interlaced?

[Mark Spano]

[Scott Smith] “what happens to the progressive scan’s extra lines”

As far as I know, they are stored on disc as is. It’s only on playback that the pulldown is added and it becomes 29.97 interlaced.

[Glenn Camhi]

So to ask the question that always gets asked yet again, but in more detail…

Source footage is 1080 24p (23.976, obviously, just shorthanding).

Final cut is same.

For the DVD…

Is there any advantage to converting to 29.97 interlaced? That’s what the post house did in the encode, but I thought we should keep it 24p. Might that play better on some DVD players, even nowadays?

Here’s a more specific question:

For anyone who has an HDTV (most folks now) and a current DVD player (say, PS3), would a DVD authored at 24p play directly as 24p without any conversion/interlacing?

And thus, would it look better than if the footage had been encoded as 29.97i?

It’s a fairly major post house, and the folks I spoke to there said I was wrong that most Hollywood DVDs are 24p. Am I? If they’re not 24p, why does advancing one frame always show a new frame, whereas advancing one frame on the interlaced DVD they gave me only shows a new frame every 2nd and 5th time?

Thanks for any expertise here!

[Jeff Greenberg]

[Glenn Camhi] “Is there any advantage to converting to 29.97 interlaced? That’s what the post house did in the encode, but I thought we should keep it 24p. Might that play better on some DVD players, even nowadays?
“

No advantage. If you flag 23.98 material correctly the DVD player will add pulldown back to 29.97 (necessary for SD)

[Glenn Camhi] “For anyone who has an HDTV (most folks now) and a current DVD player (say, PS3), would a DVD authored at 24p play directly as 24p without any conversion/interlacing?
“
I don’t think so – although some TVs/DVD players will play a true 23.98 signal for HD.

[Glenn Camhi] “Am I? If they’re not 24p, why does advancing one frame always show a new frame, whereas advancing one frame on the interlaced DVD they gave me only shows a new frame every 2nd and 5th time?
“
They’re shot 24 and the playback (the dvd player) should reintegrate that correctly for SD – interlaced with 2 frames telecine’d

Best,

Jeff G

Apple Master Trainer | Avid Cert. Instructor DS/MC | Adobe Cert. Instructor
————
You should follow me (filmgeek) on twitter. I promise to be nice.
New- my book (with Richard Harrington and Robbie Carman)- An Editor’s Guide to Adobe Premiere Pro
Compressor Essentials from Lynda.com
(older but still good) Marquee, Media Composer (3.5) and Basic/Advanced Color DVDs (1.0) from Vasst.com
Contact me through my Website

[Glenn Camhi]

Thanks for your speedy reply. I keep seeing different or unclearly worded explanations, so trying to get definitive answers.

So, is there any *disadvantage* to converting to 29.97 interlaced in the encode for DVD?

You’re saying most major studio DVDs are indeed progressive with flags, rather than interlaced, right?

[Jeff Greenberg]

You caught me at a time where I should be doing other stuff. 😀

[Glenn Camhi] “So, is there any *disadvantage* to converting to 29.97 interlaced in the encode for DVD?
“
Yes, it’ll take up 20% more space (without any additional quality. It’s the question of where the telecine occurs.

[Glenn Camhi] “You’re saying most major studio DVDs are indeed progressive with flags, rather than interlaced, right?
“

Absolutely. Don’t take my word for it. Take a look at a hollywood dvd during playback (many dvd players can show you info like fps and data rates.0

Best,

Jeff G

Apple Master Trainer | Avid Cert. Instructor DS/MC | Adobe Cert. Instructor
————
You should follow me (filmgeek) on twitter. I promise to be nice.
New- my book (with Richard Harrington and Robbie Carman)- An Editor’s Guide to Adobe Premiere Pro
Compressor Essentials from Lynda.com
(older but still good) Marquee, Media Composer (3.5) and Basic/Advanced Color DVDs (1.0) from Vasst.com
Contact me through my Website