Interlaced "PPF" Problem

[hech54]

I have two almost identical videos. Everything is the same except that
one clip is interlaced "PPF" and subsequently will not edit correctly in
my editing program (Magix this time).
Well....it MAY edit correctly but the preview/playback of the PPF video
is completely boogered and unwatchable....so I don't want to go further
until I can at least see what I am editing....know what I mean?

The other video(interlaced TFF) previews perfectly.

Anyone have any ideas how to fix it?

[jagabo]

PPF? You mean BFF (bottom field first)?

[poisondeathray]

Picture Per Field?

http://www.videohelp.com/forum/archi...s-t308205.html

Have you examined the content in avisynth or vdub (it might actually be progressive content, and the flag is giving the editor trouble)?

Have you tried other software? Maybe Vegas or Premiere?

Maybe manono is more familiar and can shed some light

[jagabo]

I would love to see a short sample of this.

[hech54]

Yes....GSpot indicates it is I/L and PPF.
It's ripped straight from a DVD but it was recently transferred to DVD (professionally) from old 80's era film.

And....short sample clips (edited in VDub) don't give Magix any problems....just when I load the entire video clip (3 minutes).

[jagabo]

You can use DgIndex to demux a small segment for upload.

Since the clip is so short and you say it works fine after VirtualDub why don't you just open it VirtualDub and save with HuffYUV compression. Or maybe you can frameserve to your editor.

[manono]

Is it a DVD sample using a field picture structure you're interested in seeing? If so, I have several. How about this one:

ppf.m2v

If you'd like a larger sample, let me know and I'll upload one to MediaFire.

[hech54]

Since the clip is so short and you say it works fine after VirtualDub why don't you just open it VirtualDub and save with HuffYUV compression.

Opening with VDub and saving it as HUFFYUV did the trick....thanks...now
it previews normally in Magix.
I'd love to save you a clip of it....but so far the only thing it opens in is VDub.
It won't open in AviDemux....or even WMP as far as that goes....but my WMP
has been sucking wind for weeks...same with AviDemux. They both have turned
into unstable monsters in the past few weeks....but that is another problem.

[jagabo]

Manono, thanks for the PPF sample. I've added it to my collection of odds and ends. It's a little hard to tell what's going on with the field blending. Do you have one without field blending?

From recent reading what I understand is each field is compressed as a progressive image. So an interlaced 720x480 frame is split into two progressive 720x240 frames and each is compressed. On decompression the the resulting images are woven back together into an interlaced frame. All within the MPEG encoder, of course. I suppose this would lead to a little less contamination (eg DCT ringing) between fields.

[minidv2dvd]

weird stuff this ppf file. vegas 8 and 9 pro won't open it. mediainfo, womble, and premiere pro cs4 think it's a normal tff interlaced mpeg-2. gspot identifies it as pff but crashes trying to render it.

was it a bollywood production by any chance?

[manono]

Do you have one without field blending?

No, sorry. The ones I own with a field pic structure are all Indian and all field-blended. I've seen a few others in the past, but don't own any that aren't field blended.

I suppose this would lead to a little less contamination (eg DCT ringing) between fields.

In my experience, the ones with a field pic structure are the very worst of the worst DVDs. I have never seen this from a reputable DVD production company. There must be some really crummy hardware encoder out there that creates them that way. My guess is that quality is the last thing on the minds of the people that foist these things on us.

[hech54]

See if this sample is what you are looking for.
The halos and the overall odd look about the video is normal.
What do you expect for an 80's music video.



ptwsample.demuxed.m2v

[manono]

Yours is interesting, hech54. It's really progressive with out-of-phase fields. It just needs them realigned again and you get a much better looking (and easier to compress) progressive video:

TFM()

hech54.mpg

[hech54]

Yours is interesting, hech54. It's really progressive with out-of-phase fields.

OK...if you say so....I'm an idiot when it comes to this stuff.


Given the nature of the DVD contents...and the probable "source" of
this material...it would not surprise me that this footage has been
converted to and from PAL/NTSC several times.

[manono]

It just means one of the fields is shifted over one frame. If the capital letter represents the top fields and the small letter the bottom fields, then ordinarily the frames for a progressive DVD are like this:

ABCDEF
abcdef

In your video they're like this:

ABCDEF
bcdefg

The fact that they were encoded using a pic structure doesn't mean much in this context as there are flags that tell how they're to be reassembled into frames. Because yours are field-shifted, they appear to be interlaced. For ordinary interlacing, every field is taken from a different point in time. With this one, pairs of fields are taken from the same point in time (the capital letter and small letter pairs). To get it looking progressive again, the fields just have to be realigned. I didn't deinterlace it, but only matched up the correct pairs of fields.

If it's to be reencoded, making it progressive again aids in compression efficiency. If you're not reencoding, then there's not much point in 'fixing' it, although many progressive scan DVD players outputting to progressive displays will deinterlace it, which may degrade the video quality.