To deinterlace or Not to deinterlace?

[SLK001]

A frame is a picture, taken at an exact moment in time that is scanned, then "split" in two, with one field (split part "A") sent first, then the other field (split part "B"). It is normally not "later" as you suggest. A lot of the modern VCRs will only display the fields from a single frame when paused (there are flags in the vertical sync pulse). This also holds true for DVD players. The "flicker" that you continue to mention would occur when older VCRs would display one field from one scene and the other field from another scene (at scene change boundaries).

But you are converting from a camcorder, so you have to determine at what frame rate was it recorded. If 29.97, then you might possibly have to encode it as progressive at 29.97. You are also going to have to determine how the video is recorded to the tape in your machine (dig out your manual). The info in your manual should dictate how to encode your video.

But I'm now totally confused... I'm going home!

[shred]

Thanks SLK001. I'm glad we're off that telecine issue. You were beginning to make me think I was totally missing something.

If the DVD player is that intelligent, then that may explain things.

If I convert in TMPGEnc with the encode method set to "Non-Interlaced" then the bit/flag is not being set on my SVCD and my DVD player thinks its progressive. But since it IS actually interlaced frames/pictures (made up of two fields at slightly different times) it gets that flicker effect when paused.

Try it and you will see what I mean.

If I convert with the encode method set to "Interlaced" then the "smart" DVD player sees the flag and knows to show just one field (either even or odd) when paused and therefore no flicker effect.

Wow, technology is so freakin amazing...

So... just because there is no flickering in a paused frame does not mean that I do not have interlaced video.

Alright teat's one step closer to figuring things out then.

I still can't figure out why my video captured at 320x240 looks as good as one captured at 640x480. EVERYONE says that there will be a noticeable gain in quality when capturing at the higher resolution. I am, however, only viewing on TV.

I would love to see someone elses EXACT capture/filter/convert settings for making good NTSC interlaced SVCD from C-VHS camcorder. I guess half the fun is figuring out what looks best to ones self. I'm just not satisfied with what I have come up with so far. I either lose the interlacing, or retain the interlacing and gain distortion.

I'll keep trying different capture/convert methods.

Thanks to all...

[Nitemare]

Greetings all!

I've decided to jump into this thread with a question.

I've been playing with various VHS capture techniques, codecs, etc., and I've been doing a LOT of online research. I read somewhere that AVIs do not support interlacing. Is this true or no?

Capturing directly to MPEG has been extremely difficult and the results are disappointing. I don't have the greatest capture card (ATI All-In-Wonder) and so I am forced to capture to AVI and then convert to SVCD.

IF it is true that AVIs don't support interlacing, then why does the de-interlace filter in VirtualDub work? So far my most watchable results are to capture at 640x480 with an MJPG codec, de-interlace and convert.

To answer a question in a previous post, capturing at ???x240 only captures the odd or even fields and is automatically de-interlaced. It IS less quality but only becomes extremely obvious when graphics are involved. I used that method until capturing a Roswell episode from the Sci-Fi channel. The little Sci-Fi logo had a bad case of the "jaggies"... capturing at 640x480 fixed that nicely, but now I get an occasional softening (blur) of the picture due to de-interlacing, which is arguably better than the full-time softening I got from my ???x240 captures.

IF AVIs support interlacing I may try the varying aspect ratio's tip mentioned earlier in the thread and then not worry about de-interlacing, but to re-state the question; do AVIs support interlacing? If they don't, am I doomed?

I've been lurking for months. It's nice to finally join in. Greetings to all!
Mark

[banjazzer]

I read somewhere that AVIs do not support interlacing.

DivX AVIS do not support interlacing.

[Dragonsf]

I can speak only of DV avi:this is definitive an interlaced avi.As avis come in different disguises, you should specify which flavour (codec/FOURCC) you are speaking off.

[SatStorm]

Avis can be interlace if the source is interlace.
Some target formats likd DiVX may not be interlace. Because they have the same extention, doesn't mean that it is the same thing.
MJPG, Huggyuv, asus codec and Uncompressed avi, all are interlace IF the source is interlace

XviD also supports Interlace, that's why it is my favorite mpeg 4 codec
I grabb and encode realtime with XviD from any analogue source, using only freeware programs, like virtualdub. The quality is amazing IMO
Just imagine: Whole farscape episode, CBR 900kb/s, 352 X 576 with CBR mp3 128kb/s audio, only 310MB. Perfect picture, realtime!

[vhelp]

Evening all.

Nitemare,

VHS:
----
for VHS sources, I would not recommend any real-time captures to mpeg.

VHS sources require a lot more work w/ the use of filters, as it is VERY
noisy, and has to be cleaned out as much as possible. And, those real-time
encoders don't have this feature (at least not yet, but given the enormous
amount of time to clean, using filtering techniques, real-time captures would
not cut it)

Best to capture VHS source, to an AVI format instead, then, through the use
of a good set of filters (filter chain) you can eliminate most noise and have
a better chance at encoding w/ good quality and slightly reduced bitrate
that would have otherwise ben quite high, due to the noise.

This takes time to master. Not all VHS are alike. Not one single filter
will work with every VHS source project, unless you build a generic filter to
use for ALL your VHS sources but with a comprimise ie, speed; quality etc.

Interlace:
----------
As other's have stated (including myself, earlier) :
* ALL sources that are: DV, and/or Analog Captured at Interlaced UNLESS,.. I
.. said, UNLESS the source is progressive (w/out Interlace) When you capture
.. such sources that have NO Interlace in them, you capture card or DV card
.. will NOT have them in your final AVI.

divX/XviD etc.
--------------
BOME, these "final" sources (or AVIs) are progressive, because those that have
encoded them (again, "final") applied "some form" of de-Interlace on them. And
not all of them are done well to begin with.
So, your argument on "some sources are not interlace" is invalid unless you
are arguing "for DV or Analog Capture" ..."sources are interlace"

I good de-Interlace technique will look almost as good as the "source" but not
exact (to the experienced)

When a frame is Interlaced, it is done within Fields (two fields make a Frame)
Those Interlaced fields are not exact and not perfect. And add to that, that
where or whoever "encoded" the source (before you captured it) if there encoding
technique was not enough to compensate for those fields that overlap during
the encoding, (as is almost always the case) then the final source will have
artifacts in them. And, although when you view them via your broadcasters
airing time on TV, you don't notice it, because the bitrate is high enough, and
the source is clean enough (to an extent) and as Interlaced on to your TV set,
and speed it's airing (29.970 fps) you WONT notice those blocks or artifacts
when watching TV (your broadcasters aring of ie, Farscape) (unless you are one
with trained eyes to catch them)
BUT, once you capture that source ie, Farscape, and your have a closer look at
the footage in your editor ie, VirtualDub, you will indeed, see those artifacts
that I just mentioned above, in your videos frames. Usually, during the Interlace
frames.
NOW, you want to encode those same frames. NOW, its no wonder why you are
STILL not getting what you thought you should get when you capture and encode
your favorite TV show - - because you didn't know (were ablivious, till now)
what was missing in the (this) recepie.

There are more issues to talk about here, but I sense I've gone over most of
you guys heads. So, i'll stop here, and leave the remaining (if you know what
i'm talking about, and left) to those that do know, and are willing to ANALise
or add in what i just stated above. Ok? Now that I've helped you to "Wake up,
and smell the coffee", you will be more prepared to accept the reasons or why's
in your final video encodes quality !!

The THUMB is:
-------------
MPEG-2 .. Leave Interlaced, but use HIGH bitrate ie, DVD projects
MPEG-2 .. if source is very good quality, LOW bitrate ie, 2520 kbts ok w/ Interlace
MPEG-2**. however, a good de-Interlace algorithem yields excellent results too.
MPEG-1 .. DE-INTERLACE, DE-INTERLACE, DE-INTERLACE, DE-INTERLACE
divX .... DE-INTERLACE, DE-INTERLACE, DE-INTERLACE, DE-INTERLACE
......... note, on some encodes I did, Intelaced was fine for TV-OUT cards, but you
......... have to experiment to see what works, ie, frame resizing techniques will
......... reflect Interlace artifacts or strange output viewing.
PCVIEWINGE-INTERLACE, DE-INTERLACE, DE-INTERLACE, DE-INTERLACE
......... note, PowerDVD and WinDVD have built-in De-Interlace (bob) but
......... sometimes the quality is not so good. So, experiment on such, if you are
......... planning on viewing w/ these app.
NOTE: ... Media v9 (XP OS) is suppose to have a very good real-time De-Interlacer,
......... so I heared, but that remains to be read (from this FORUM - I haven't heard
......... yet)

Well, i'm off to start dinner -- spagetti tonight. Yum!!
-vhelp
BOME=based on my experience