DV to DVD conversion & interlace problems using ffmpegx

[soholounge]

hi, i'm using the latest version of ffmpegx,
and i'm confused about the de-interlace option.

if i don't check the de-interlace option, then my DVD is unwatchable on a TV.
if i DO check the de-interlace option, then the DVD looks fine on a TV (and computer).

isn't that the opposite of what's supposed happen?

my source is DV (interlaced, bottom field first)
i edit in FCP (settings are for NTSC DV - bottom field interlaced)
then output to qt file.
that goes to ffmpegx, and i use the DVDffmpeg preset.

if i use the preset, and leave the de-interlace option unchecked, then my DVD should be interlaced and watchable on a standard (non-progressive scan) dvd player and TV, right?
but it's unwatchable.
and if i check the de-interlace option, then the output would be Progressive, right?
but that's the DVD that can be watched without jitters on a standard TV.

what gives?

btw, i'm on an intel mac, if that makes any difference.

thanks.

[soholounge]

anybody?
i'm sure somebody else out there is using ffmpegx to author DVDs from DV cam footage?

-paul

[gadgetguy]

I don't use ffmpegx and I don't use mac, but it sounds like the field order is being processed wrong when you are encoding interlaced (unchecked). In other words, you are feeding it bottom field first footage, but it is being processed as top field first.

[soholounge]

thanks for your thoughts gadgetguy,
i think you're right.

i wonder if Major could chime in and let me know if there's something i'm doing wrong, or if it's a bug?

[jpschuck]

hi, i'm using the latest version of ffmpegx,
and i'm confused about the de-interlace option.

if i don't check the de-interlace option, then my DVD is unwatchable on a TV.
if i DO check the de-interlace option, then the DVD looks fine on a TV (and computer).

isn't that the opposite of what's supposed happen?

my source is DV (interlaced, bottom field first)
i edit in FCP (settings are for NTSC DV - bottom field interlaced)
then output to qt file.
that goes to ffmpegx, and i use the DVDffmpeg preset.

if i use the preset, and leave the de-interlace option unchecked, then my DVD should be interlaced and watchable on a standard (non-progressive scan) dvd player and TV, right?
but it's unwatchable.
and if i check the de-interlace option, then the output would be Progressive, right?
but that's the DVD that can be watched without jitters on a standard TV.

what gives?

btw, i'm on an intel mac, if that makes any difference.

thanks.

Hmm, i'm not 100% sure but I guess that "de-interlace" filter applies to the _source_, not to the output movie. I guess interlacing is a process that must be "recalculated" from a de-interlaced source with each encoding step. So you have to enable this option when you're encoding from an interlaced DV source.

Some information there (look the "Problems caused by interlacing" part) :
http://en.wikipedia.org/wiki/Interlace

I don't know how to choose between an interlaced or progressive output with the ffmpeg engine (interlacing mode selection is in the "options" tab when using"mpeg2enc" engine).

Anyone can confirm this ?

[soholounge]

thanks jps,
if you're right, and i should probably just encode with mpeg2enc, but i can't seem to get good results with that!
ffmpeg has worked better for me, (besides the de-interlace confusion)

i wish someone would confirm your theory, though.

[t42]

I have a de-interlace probelm with conversion "DV-->Divx": with ffmpegx the resulting video looks wavy, but with mencoder it's ok. Is there any rational explanation for this issue?