How to make a DVD interlaced?
 

I'm trying to generate interlaced files with Compressor, to make a DVD. My source material is progressive. I'm not sure what I have to do.

My source material is 720p. It should downsample each frame, and then take the correct field. Instead, it only downsamples every other frame, and takes both fields from it, which is a boneheaded way to do it. It makes motion jerky instead of smooth.

I guess a related question is whether I should produce DVDs as progressive or interlaced these days, since most displays are inherently progressive. And whether I should use 4:3 or 16:9.

Encode progressive if the source is progressive...This has more to do with how the encoder does it's job.

The nature of the DVD is to send an interlaced signal out to the TV....There isn't a DVD standard that throws out progressive frames for playback..

As far as progressive playback is concerned, either the DVD player or TV will regenerate to a progressive signal..

I disagree with the logic of encoding progressive if the source is progressive. If the source has a sufficient framerate, then each frame in the source can be converted to a field in the output.

Compressor is not doing this, it's taking every other frame, and converting it into both fields. It's throwing the other half of the frames away.

Is there a way to make it handle the conversion better?

John....
Most Mpeg2 encoders have an option for Progressive or Field encoding parameter. This allows the encoder to do either an alternate scan, or a zig zag scan..
It's an internal thing...

This will not effect playback..It's strictly an option for internal usage as far as the encoder goes..

Again, DVD was intended for interlaced playback..You can have progressive frames as a source, but the flags in the video stream tell the DVD player to playback the proper field information..

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In essence, that's how a DVD is played back.

How about a few screenshots, and how about your playback methods??
This shouldn't be an issue...

A screenshot wouldn't show anything, since it's a problem with motion smoothness, not with any individual frame.

Where is the field encoding parameter in Compressor? I think this may be what I'm looking for (assuming that it also changes its encoding to match the setting given to the MPEG algorithm).

I meant a screenshot of your encoder values....
As far as playback is concerned, how are you viewing the final product?? Is it playing back choppy??

Actually, I found the setting I was looking for, you have to click the gear and turn on Frame Controls, and then you can choose an output fields setting. As you said, you also have to tell the encoder, the same as you have to tell it aspect ratio.

I wouldn't say that playback is choppy, but it looks like 30fps instead of 60fps, and a little extra weird 'cause half the frames are missing.

Now I gotta tell it to align my edits on even frames 'cause otherwise that looks weird. xD

It's a bit confusing because the Encoder controls are what gets sent to the compression algorithm (and possibly on to the player), whereas Frame Controls (in the case of interlacing) and Geometry (in the case of cropping) control what's actually done to the video before it's compressed.

Thanks to everyone who answered me.

There are several possible ways to do it, and I'm still trying to figure out which is best. I have to decide if I should optimize it for regular TV's or for progressive playback. Everyone plays stuff on their laptops these days.

I'm going to take a few samples over to my mom's and try them on her TV. I don't have a natively interlaced display, and I think it's the same for a lot of people.

I've become convinced that the people who say they can't get good output to DVD just have some settings wrong in Compressor. I think the Final Cut studio is capable of good DVD output if used properly, but the default settings don't do a good job.

You seem to worry about things that aren't necessary my friend.

That's the thing about DVD playback software....Programs like PowerDVD, WinDVD, etc...Have built in deinterlacers...I'm not sure about the Mac end, but whatever the case, the designers of the playback programs took this into account...

Same with the hardware end. TV manufacturers, and DVD player take this into account when playing back interlaced material..Information gets doubled, and then weaved back together..

But none of this should need to concern you, as 720P downconverted to 480i or p should be straightforward.

Good luck!!!

I've never had a problem taking 720 30p and making a great DVD using the FCS process. I also don't go overboard with my settings. My technique is that the HD footage and down convert it to SD before making the 2-pass MPEG files in Compressor. Sometimes going from HD directly to MPEG2 gets a little gummy (and takes a real long time) although that was back in FCS2. Perhaps you can experiment with this technique.

Now the issue of 60p into interlaced 60i is an interesting challenge that I haven't encountered yet. I can see where there might be transcoder programming issues. The best way would be a direct frame to field transcode but to know how much info would be lost is scary. 720 down to 240.

Also, I believe that the DVD standard allows for 60 or 50 interlaced and 24p. 30 and 25 progressive are placed within the 60/50 interlaced standards.

The best tool I have seen on a Mac to do a proper 60p to 60i conversion is Shake which Apple no longer sells. Pitty really because it did an amazing job. With Shake you have an amazing level of control over the picture quality down to the sub pixel level. Really an amazing tool. Of course to use it means rendering a version of your project from FCS. Loading it into Shake rendering a new quicktime file. Then finally loading that into Compressor to make your mpeg2 file. Kind of a pain but amazing results.