How to set anamorphic property (or PAR) of DV

[letsbefrank]

Hi,

Great forum. Hope this question hasn't been asked too many times.
My search didn't show a result but I bet someone has asked this
before.

When I shoot in 16:9 mode on my Sony vx2100 (which I understand
from this forum is shooting 16:9 the wrong way - i.e. not
using full height resolution of the CCDs), the frames are
stored using the full 480 lines of resolution (as a result
of resizing performed by the camera - not ideal I know). I
capture the DV as Type II using WinDV and the firewire connection
on my PC. Something about the resulting .avi file tells
Windows Media Player that this is an anamorphic image because
WMP displays this with the appropriate black
bars at the top and bottom. I suspect there is a correct Pixel Aspect
Ratio property stored per frame but GSpot doesn't seem think it
is. GSpot reports the Frame size is 720x480, the FAR is 1.500 (3:2),
the PAR is 1.0, and the DAR is 1.500 (3:2). These are the same
values it reports for video shot in 4:3 mode.

So something about the frames tell WMP how to correctly display
the image but exactly what that is and what tools are available
for setting that property manually I don't know.

Also, not surprisingly this anamorphic/PAR property is
not retained in clips created by avisynth or VirtualDub.

I'm wondering what I can do
to retain or reset this property for those cases where I
want to edit the DV with one of these tools but don't want to
resize and add the black bars explicitly...so programs like
WMP can recognize the anamorphic nature of
the recording and perform their own interpolation automatically
when appropriate.

The answer will help me not only with video I've shot so far
using the inferior 16:9 mode of the Sony but also later on if
I get a 16:9 converter lens and shot in 4:3 mode and want to
manually set the anamorphic/PAR property of the .avi.

Thanks,
-Frank

[bb]

I'm afraid there is no working PAR / DAR support in AVIs - you'd have to use a different container like Matroska. Of course you can use a player with aspect ratio options, e.g. ZoomPlayer, but then you have to switch the aspect ratio manually. It won't recognize an aspect ratio in AVI files either.

bb

[letsbefrank]

Thanks bb. That helps explain why I haven't found any
tools to do what I'm asking for.

But anyone have any idea how Windows Media Player can tell the
difference between DV stored in avi that I recorded in 4:3 mode
where it displays no black bars above or below and that which
was recorded in 16:9 wide mode where it does display black bars
above and below? In both cases, the frames are 720x480.

-Frank

[bb]

I guess your 16:9 video is letterboxed, not anamorphic, which means that the black bars are encoded into the (4:3) video.

bb

[letsbefrank]

The source doesn't have the letter box. I've
been playing with these same avi videos using avisynth
and virtualdub and both show me a stretched 720x480
picture. Only WMP (and the camera) seems to know (or at least care) about
letterboxing the image. Why WMP doesn't just show the frame
as 16:9 I don't know but don't care too much. Since my
question has now boiled down to figuring out how and why
WMP can treat the avi differently from any of the open source
tools, does anyone have a WMP forum suggestion? If I find the
answer elsewhere, I'll post it here.

Thanks.
-Frank