Upper - Lower Fields...No Fields...

[GRAMOPHONE]

I see that in most editing programs when rendering a final project one can chose which field one wants the final rendering.
In most cases I always use "lower fields first".
I have noticed, however, that sometimes this produces some kind of jerking movement on screen.
Is it mandatory to render with field when your final product is DVD?
I took a movie and copy a piece of footage of it to analize the frames and I noticed that it has no fields at all. All film frames were captured without adding field.
How can a movie DVD plays so smoothly without having fields?
Technically a TV screen requires field frames to produces smooth movement without jerkiness. Am I wrong or right about all this.
Any explanation will be appreciated.

Thanks

[guns1inger]

It is called 'Progressive', where each image is a complete frame, instead of a composite of two fields. The field are produced by the hardware when it outputs to the TV. Newer televisions (Plasma, LCD, newer CRT models) can take progressive images directly, usually through component or better input.

[daamon]

Hi GRAMOPHONE,

Whatever media you're storing your footage on (video cassette, CD or DVD) - if it's for playback on (EDIT: standard) TV, the footage must be interlaced.

When encoding, my understanding of the "which field first" setting relates to the source as opposed to the output.

Typically, DV tends to be lower field first - but not always. When you notice the jerking movement you described, it means that the field order of the source is the opposite to what you identified in the encoding.

I hope that helps. Good luck...

[GRAMOPHONE]

Thank you, guys...

[GRAMOPHONE]

guns1inger,
According to your answer then the DVD player produces the fields to be sent to the TV monitor.
That means that if I produce a project with complete frames [NO FIELDS] and have my end project as DVD, then it supposed to play smoothly.
Is that right?

[edDV]

A DVD can be encoded interlace or progressive.

A general rule is a natve interlace source should be encoded as an interlaced MPeg2 for the DVD. The reason for this is the process of deinterlacing video using typically available software is highly destructive.

Even if the TV is progressive, the DVD should be encoded interlace. Every progressive TV has a hardware deinterlacer that almost always is superior in performance to typically available software deinterlacers.

The big exception is interlaced source material that is derived from a natively progressive source such as film. In this case, it is possible that the original progressive frame can be reassembled from fields. In PAL this is a simple matter. In NTSC, an inverse telecine (IVTC) software process can be applied.

Ref: http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm

The probable success of the ITVC process depends on the purity of the 2:3 field sequence. An unedited movie transfer has the highest probability of a clean IVTC back to 23.967 fps progressive. Programs that have been edited will have many IVTC errors unless manually constructed.

Interlace encoding of telecined material for DVD will maintain the 2:3 field sequence and the video will play fine on an interlace TV.

Some progressive DVD players and most progressive HDTV sets have internal hardware IVTC (aka "cinema") capability that works realtime by detecting and processing the 2:3 fields into a progressive 59.94 frames per second sequence. Quality varies.

Progressive DVDs played in interlace mode output in 2:3 field sequence @ 29.97 fields per second over NTSC analog outputs (or Y, Pr, Pb set to interlace).

Progressive DVDs played in progressive mode output at 59.94 frames per second through Y, Pr, Pb or through DVI-HDMI outputs if present. The 59.94 fps sequence is constructed by repeating the 23.967 progressive frames in a 2:3 sequence.

So in conclusion:

Encode interlaced with the correct field order and it will always play smoothly on an interlaced TV.

Attempt IVTC only if you know your source is film and you know what you're doing.

Avoid software deinterlacing natively interlaced material except for special purposes such as extreme compression for low bandwidth internet streaming or for small progressive displays where 240/288 vertical lines of resolution is adequate.

[rhegedus]

Possibly related to this:

DVD (vob) to DV (avi) becomes terribly shaky