Does DV-AVI preserve interlacing?

[acton]

Hello everyone,

Does the DV-AVI file format preserve interlacing?

Here's my situation and the reason I ask the question:

I've captured an analog camcorder signal with Pinnacle DC10+ and Studio 8.
I'm using Custom settings .... i.e. Full Horiz Resolution [640x480],
capturing Both Vertical Fields and Data Rate set to 6000 KB/sec. The
captured file is saved as an AVI with the following settings: Pinnacle DCxx
MJPEG Compressor, 640x480 resolution, 29.97 fps & 6000 KB/sec data rate.

If I load this file back into Studio 8 and "print" it out to tape (via the
"Make Tape" tab and the DC10+ analog output port) it looks great on tape
and TV monitor.

However, if I import the same AVI file into Movie Maker 2 (which loads it
just fine), do some small edits (fade-in, fade-out), save it as DV-AVI
(which is the best choice available in Movie Maker), convert the type I
file into type II, load the type II file back into Studio 8 and "print" it
out to tape again (via "Make Tape" tab and the DC10+ analog output port)
..... it looks all "jumpy". No pixelization or blockiness, but very hard on
the eyes!

Is the jumpiness due to loss of interlacing or is it due to some other
degradation in the process I've described?

thx in advance!

BTW ... the reason for moving things back and forth from Studio to MM2 is
that I would prefer to edit in MM2 (only because I'm familiar with it
already and the fact that I've read some pretty awful horror stories about
Studio 8 crashing all the time on WinXP systems .... although Studio hasn't
crashed on my system yet after 2 days of capturing short 1-minute clips).

 

[skailur]

I believe that the DC10+ uses a different field order than DV does. MM2
is probably assuming a particular field order when you open the DC10+
AVI, and if it's the opposite of what it really is, the video will be jumpy?

Perhaps you can use the SwapFields AVISynth filter to see if that fixes
your problem:
http://www.avisynth.org/index.php?page=SwapFields

Hopefully field swapping will be all that it takes. If not, read:
http://www.codecpage.com/DV.html

Scroll down to DV Field Order Problem. It seems that DV is the one
with the wierd non-standard "bottom field first" field order (not the
DC10+ which uses the standard "top field first").

A complete solution seems to be: to swap temporal and or spacial field
order using VD's Smartdeinterlace filter.

 

[-]

acton wrote:
I believe that the DC10+ uses a different field order than DV does. MM2
is probably assuming a particular field order when you open the DC10+
AVI, and if it's the opposite of what it really is, the video will be jumpy?

Perhaps you can use the SwapFields AVISynth filter to see if that fixes
your problem:
http://www.avisynth.org/index.php?page=SwapFields

No. This literally swaps the fields within a frame. So line 0 becomes
line 1 and line 1 becomes line 0 (and so on). This causes spacial
scrambling of the image in the frame because line 1 contains spacial
information which is *beneath* line 0, so it's no good inverting them.
This would just invert each pair of lines in the picture.

The simplest solution if your video editing program will do this it to
shift ALL of the lines in a FRAME in unison up or down by 1 line. So
line 0 becomes line 1, line 1 becomes line 2, line 2 becomes line 3
and so on. This effectively makes the top field's lines move into the
bottom field, and the bottom field lines into the top field with NO
spacial scrambling.

This does however mean that you lose a single line of the picture
information on the top (or bottom) line, but this is a small price to
pay considering that the line will not be visible on most TV screens.

Another technique is to shift all of the fields forward or backward by
1 field position. In the follwing, frames are separated by a "-", and
the fields are top "T" or bottom "B" followed by a sequence number. So
the shift converts

T1B1-T2B2-T3B3-

which is top field first into

B1T2-B2T3-B3T4-

which is bottom field first.

But this technique may introduce a slight de-sync of the sound track.
However I *think* that I saw somewhere in the avisynth documentation
that you can do this in avisynth and it will also shift the soundtrack
(but I can't be certain of this!).

Colin

 

[FLY135]

Will Dormann <[email protected]> wrote in message

No. This literally swaps the fields within a frame. So line 0 becomes
line 1 and line 1 becomes line 0 (and so on). This causes spacial
scrambling of the image in the frame because line 1 contains spacial
information which is *beneath* line 0, so it's no good inverting them.
This would just invert each pair of lines in the picture.

Sorry but he is correct. If you have the field order incorrect then when
you play the video back to a TV it will appear jerky or jumpy. The exact
interpretation of his use of jumpy is still in question but it could fit the
problem as described by Will. If the field order is incorrect then
horizontal motion will not be smooth. Any horz motion will appear to be
jumpy or jerky. Since most video has more horz motion than vertical, this
is the best way to describe it.

 

[Samuel Paik]

Another technique is to shift all of the fields forward or backward by
1 field position. In the follwing, frames are separated by a "-", and
the fields are top "T" or bottom "B" followed by a sequence number. So
the shift converts

T1B1-T2B2-T3B3-

which is top field first into

B1T2-B2T3-B3T4-

which is bottom field first.

But this technique may introduce a slight de-sync of the sound track.
However I *think* that I saw somewhere in the avisynth documentation
that you can do this in avisynth and it will also shift the soundtrack
(but I can't be certain of this!).

Even if there's no explicit command for that in AVISynth (I don't
remember seeing one last I looked), it is pretty trivial to insert
or remove 16 ms of audio to keep the audio in perfect sync. Actually,
I tend to split the audio and video fairly early on in my processing
and combine them at the end in my AVISynth scripts.

Sam

who has some captures with TFF and others with BFF (captured with
different hardware)...