Field Order Problem?

fammonti wrote on 10/8/2004, 6:06 AM
I have a problem which leaves me somewhat perplexed.

My workflow is a follows:

1. Capture from VHS throug the built-in converter of my Sony DCR-TRV22E
2. Analog noise filtering through Virtualdub with General Convolution and Temporal Cleaner filters
3. Editing in Vegas
4.Rendering to AVI DV
5.MPEG2 encoding with Procoder 2
6.DVD authoring with DVD Workshop 2

I have found out that the field order of the render AVI DV (step 4) is to be upper field first and consequently the field order of the MPEG2 (step 5) is to be upper field first as well. Thus the need to change the field order does not allow me to use frame serving to Procoder.

If in both steps I use lower field first the result is a video behaving as if the field order were had been inverted.

Can anyone explain this?

Greetings from Italy.

Andrea

Comments

taliesin wrote on 10/8/2004, 6:21 AM
At the end of your second step - when you export the file from VirtualDub - which file format and which codec do you use?

Marco
fammonti wrote on 10/8/2004, 6:39 AM
I use "Save as AVI" witg Panasonic DV Codec

Andrea
taliesin wrote on 10/8/2004, 11:31 AM
Ah, stop. I remember there is a strange behaviour in Procoder. I think (but not sure about it) Procoder needs to render Upper Field MPEG for DVD use. I think if you render out of Vegas using Lower Field then setting the field order to Upper Field for rendering with Procoder should be fine too.

Marco
BJ_M wrote on 10/8/2004, 12:24 PM
procoder doesnt need to render to upper field first -- but you do have to tell it the source field order as it just does a guess based on the same file type.

you could increase your quality by frame serving out of V-dub to vegas and frame serving from vegas to procoder .. saves a few extra compression steps (and time) ..

Temporal Cleaner (the built in one) works better on progressive material - you may want to look at using 2d cleaner or the very high quality (but slower) MSU de-noiser .. the Temporal noise cleaner in procoder is very good also ..
johnmeyer wrote on 10/8/2004, 1:56 PM
Speaking of cleaning, here is some information I just emailed to someone. This is a long post, so if you have no interest in cleaning VHS for transfer to DV or DVD, then quick, click on something else.

I now use AVISynth to process VHS and other analog video. I use this rather
than VirtualDub because the processing is MUCH faster, and there are far
more plugins available.

Analog videotape recordings, especially VHS, suffer from two major problems:
chroma artifacts and random noise spots ("snow"). The chroma problems are
caused primarily by the way in which analog video is stored on VHS tape,
whereas the random noise is due to the poor signal to noise ratio in most
consumer tape systems, especially at lower tape speeds. Fortunately, the
chroma problems can be almost completely eliminated with the proper filter,
without introducing distracting artifacts. doom9 has an excellent discussion
of the various type of chroma noise here:

Chroma Artifacts

There are dozens of plugins available for VirtualDub and for AVISynth to fix
these problems. I originally started with VirtualDub because it is an easier
program to use, but eventually opted for AVISynth because it is much more
powerful and, because of how it is architected, the same plugins that exist
on VirtualDub, but which have been re-written for AVISynth, run much fast in
that environment.

I use the following AVISynth script for all my analog captures. It uses just
two plugins. One is called CNR2 and is a recompilation of the Mouchard
VirtualDub chroma noise reduction plug-in for VirtualDub. The other is a
relatively unknown noise reduction plug-in called Fluxsmooth. It is a
combination of spatial and temporal smoother. These combination smoothers
are quite clever because they try to give you the best of two different
approaches to removing the "snow" noise. The first approach "averages"
adjacent pixels in a single frame. This "softens" the video somewhat, but
tend to remove the dots. The second (temporal) approach does the same thing
across frame, that is across time (hence the word "temporal"). If have a
picture taken on a tripod of a still scene (like a landscape), then the only
thing moving from one frame to the next is the noise. If you average a few
frames together, the noise disappears, but the picture remains untouched.
However, when there is lots of motion, this approach produces "ghosting"
because you are averaging pixels from earlier and later frames into the
pixels that make up the current frame. By contrast, the first approach
(where the averaging is just done on one frame), produces no artifacts with
fast motion. Since fast motion is already blurry, the extra blurring is
hardly noticed. Thus, ideally you want a filter that uses spatial filtering
on the fast moving portions of the video, and temporal filtering on the slow
moving portions.

Fluxsmooth is such a filter, although in the script below, I have chosen to
use just the temporal filter. I have found that most people are accustomed
to seeing some small amount of noise in video and if you use the temporal
filter at a low setting, you leave enough noise to make the result look
"natural," but you never use enough of the filter to start getting the
ghosting. The author optimized the filter so that when used in the
temporal-only mode, it runs several times faster than its hybrid
counterpart.

As a result, this script runs amazingly fast, and is able to feed video
directly into most MPEG encoders at close to the speed that they can run.

For the following, I assume that the user has installed AVISynth 2.5 or
above (http://www.avisynth.org/), and has downloaded CNR2
(http://mf.creations.nl/avs/filters/) and Fluxsmooth
(http://www.kvcd.net/sansgrip/avisynth/). You then copy this script to
notepad, change the AVI file name in the script to match the name and path
of the AVI file you are going to "clean," and than save this script file
with the extension AVS. Open this AVS file in your MPEG encoder (or an other
video program that supports AVISynth script files) and work with your clean
video.

Here's the script:
=========================
#Serve RGB32 from Vegas. If going into Mainconcept MPEG encoder,
#convert back to RGB32 in this script. Check the RGB 16-235 box in the
Mainconcept encoder.
#LoadPlugin("C:\Program Files\AviSynth 2.5\plugins\Old
Plugins\LoadPluginEx2.dll")
#LoadPlugin("c:\Program Files\AviSynth 2.5\plugins\Old Plugins\DustV5.dll")
#loadplugin("c:\Program Files\AviSynth 2.5\plugins\despot.dll")


# CNR2 does NOT need to be fed deinterlaced frames
loadPlugin("c:\Program Files\AviSynth 2.5\plugins\Cnr2.dll")

AVISource("D:\Frameserver.avi")

#These plugins require color space conversion
converttoYV12(interlaced=true)
Cnr2("oxx",8,16,191,100,255,32,255,false)
fluxsmoothT(7)

#DeSpot(p1=20,p2=8,pwidth=240,pheight=5,mthres=14,mwidth=20,mheight=15,inter
laced=true,merode=43)

#Pick the color conversion for final output
#converttoYUY2(interlaced=true)
ConvertToRGB32(interlaced=true)

#This plug-in REQUIRES RGB colorspace
#Pixiedust(limit=5)
============================
Notice that I left a few additional lines in the script, which I have
commented out, to show how to use two other plugins. Lots of people like the
Pixiedust function of the Dust plug-in for removing noise. I personally find
it unbearably slow, and didn't like the results as well as Fluxsmooth. If
you want to use it, you have to put the dll in a different directory from
your other plugins, and you also have to load the LoadPluginEx2.dll file
prior to loading DustV5.dll because this is an older program that is not
directly compatible with version 2.5 of AVISynth.

The other plug-in is actually extremely interesting and quite useful for
several situations. It is also a bear to figure out and set up. Despot gets
rid of, well, spots! These can be dust spots on film; "vacuum-cleaner" type
static on over-the-air broadcasts; tape dropouts, either from bad tape or
from bad heads; and best of all (for me at least) "laser rot." When you get
it set up correctly, it is about as close to magic as anything could be. All
the flashing white spots (in the case of video static or laser rot), just
disappear. However, if you aren't careful, you will find that bright
horizontal lines (like you get from partially open Venetian blinds) can
appear and then disappear as the camera moves up or down. Also, bright
buttons on people's clothes will disappear when they move.
BJ_M wrote on 10/8/2004, 3:02 PM
Flaxen VHS noise reduction filter for virtualdub is sort of the same thing ...if you use only v-dub


AudioIvan wrote on 10/8/2004, 5:20 PM
There are some bugs in Dust, so for interlaced sources you'll have to use
ViewFields()
PixieDust(limit=5, color=YUY2, interlaced=true)
UnViewFields()

AudioIvan