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Simple Virtualdub question (audio editing, save as "old av..

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Anonymous
December 16, 2004 10:59:24 AM

Archived from groups: rec.video.desktop (More info?)

Hi,

When one loads an AVI into Virtualdub, extracts the audio for editing
(i.e. remove hiss, normalize) and then re-attaches the audio with
Virtualdub and saves the final result, is the AVI video re-encoded?

The reason I ask is that I have several VCD resolution AVI files and
the audio is pretty badly in need of restoration. However, I don't
want to have to put the video through yet another degrading re-encoding
process. If I had to choose one, I'd rather have the bad audio than
worsened video.

I'm HOPING to hear that Virtualdub merely re-attaches the audio and
does not re-encode the video when you save the final result.

Also, my WINNOV VIDEUM AV capture card captures AVIs with the WNV1
codec, which can be burned to VideoCD no problem with Nero, but until
you do that, not many applications can play these AVIs. However, when
I load them into VirtualDub and "save as old AVI" I can view them with
any application. I am wondering: does this process re-encode the video
as well, or merely change something in the file without degrading the
video.

Thanks
Brent Santin
woodenflutes@yahoo.ca
Anonymous
December 16, 2004 1:41:49 PM

Archived from groups: rec.video.desktop (More info?)

Ginchy wrote:
> I would imagine it would only re render the audio.
>
> why not use the free tmpg and strip out the audio, fix it, and
remerge the
> audio

Oh, I didn't know Tmpg could do this (I've only been capturing video
for a week). What is the advantage to using TMPG over VirtualDub to
strip/recombine audio? They are both free it seems....

> as to your 2nd q it fixes the header on the avi thats all!
That's good news!

Brent
Anonymous
December 16, 2004 3:53:49 PM

Archived from groups: rec.video.desktop (More info?)

Okay....another question then: Virtualdub, under the VIDEO menu in
Capture mode, has both a FORMAT and a SETTINGS choice (at least with my
card installed - WINNOV VIDEUM AV). When I choose either of these, it
opens up the WINNOV control panel (the card's native software) where i
can set the capture resolution.

A little further down the VIDEO menu is a CUSTOM CAPTURE RESOLUTION (or
something similar) choice. Here I can set the capture resolution
within the VirtualDub program itself.

When I set the custom capture resolution within Virtualdub, the preview
image does seem to resize itself to the custom resolution specified,
but I wonder if this is a 'true' capture at this resolution, or merely
an interpolated re-sizing done by Virtualdub. Which capture resolution
overrides which? i.e. if I have the WINNOV control panel set up to
capture 320x240 and from within VirtualDub set the CUSTOM capture
resolution to 640x480, will the resultant AVI be "truely" 640x480, or
will the card capture at 320x240 and feed this to Virtualdub, which
will then do an "upsampling" to 640x480? Obviously, if the second is
happening, then the result will be a 'fake' 640x480 with no greater
detail in the image.

Thanks!

Brent
woodenflutes@yahoo.ca
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Anonymous
December 16, 2004 8:36:17 PM

Archived from groups: rec.video.desktop (More info?)

I would imagine it would only re render the audio.

why not use the free tmpg and strip out the audio, fix it, and remerge the
audio

as to your 2nd q it fixes the header on the avi thats all!


<woodenflutes@yahoo.ca> wrote in message
news:1103212764.566855.176920@f14g2000cwb.googlegroups.com...
> Hi,
>
> When one loads an AVI into Virtualdub, extracts the audio for editing
> (i.e. remove hiss, normalize) and then re-attaches the audio with
> Virtualdub and saves the final result, is the AVI video re-encoded?
>
> The reason I ask is that I have several VCD resolution AVI files and
> the audio is pretty badly in need of restoration. However, I don't
> want to have to put the video through yet another degrading re-encoding
> process. If I had to choose one, I'd rather have the bad audio than
> worsened video.
>
> I'm HOPING to hear that Virtualdub merely re-attaches the audio and
> does not re-encode the video when you save the final result.
>
> Also, my WINNOV VIDEUM AV capture card captures AVIs with the WNV1
> codec, which can be burned to VideoCD no problem with Nero, but until
> you do that, not many applications can play these AVIs. However, when
> I load them into VirtualDub and "save as old AVI" I can view them with
> any application. I am wondering: does this process re-encode the video
> as well, or merely change something in the file without degrading the
> video.
>
> Thanks
> Brent Santin
> woodenflutes@yahoo.ca
>
Anonymous
December 16, 2004 9:02:02 PM

Archived from groups: rec.video.desktop (More info?)

woodenflutes@yahoo.ca wrote:
>
> Hi,
>
> When one loads an AVI into Virtualdub, extracts the audio for editing
> (i.e. remove hiss, normalize) and then re-attaches the audio with
> Virtualdub and saves the final result, is the AVI video re-encoded?

No. At least not if you set the video on direct stream copy.

> The reason I ask is that I have several VCD resolution AVI files and
> the audio is pretty badly in need of restoration. However, I don't
> want to have to put the video through yet another degrading re-encoding
> process. If I had to choose one, I'd rather have the bad audio than
> worsened video.
>
> I'm HOPING to hear that Virtualdub merely re-attaches the audio and
> does not re-encode the video when you save the final result.

re-attach is called "remux" :) 

> Also, my WINNOV VIDEUM AV capture card captures AVIs with the WNV1

Doesn't sound good, but ok ... There's no way to select huffyuv or
mjpeg?

> codec, which can be burned to VideoCD no problem with Nero, but until
> you do that, not many applications can play these AVIs. However, when
> I load them into VirtualDub and "save as old AVI" I can view them with
> any application. I am wondering: does this process re-encode the video
> as well, or merely change something in the file without degrading the
> video.

I guess you didn't set 'direct stream copy' here, so yes, the video
is re-encoded provided you selected a codec. If you didn't select a
codec
the video is just decompressed (size will be very large in that case).

Wilbert
Anonymous
December 17, 2004 9:19:21 AM

Archived from groups: rec.video.desktop (More info?)

Thanks for the info. I did some experimentation last night and I did
confirm that the SET CUSTOM CAPTURE SIZE (or whatever) in Virtualdub
does indeed over-ride the settings in the native WINNOV VIDEUM AV
control panel. When I choose a custom capture size in Virtualdub and
THEN go back and look in the VIDEUM AV control panel, the size reported
there is indeed the new size I specified in Virtualdub.
Thanks for your help.

Brent Santin
Anonymous
December 17, 2004 9:22:06 AM

Archived from groups: rec.video.desktop (More info?)

Last evening I played with TMPEG Encoder again, and found features you
were talking about. I was able to strip the audio from within TMPEG,
and more importantly, re-combine the "edited" audio with the video from
within TMPEG while it encoded the MP3. I think this is better than
recombining it withing Virtualdub to an AVI, and THEN converting it to
an MPEG with TMPEG. I'm not totally sure, but it also seems the video
quality was better in the end. Thanks!

Brent Santin
Anonymous
December 17, 2004 4:12:40 PM

Archived from groups: rec.video.desktop (More info?)

woodenflutes@yahoo.ca wrote:
>
> Okay....another question then: Virtualdub, under the VIDEO menu in
> Capture mode, has both a FORMAT and a SETTINGS choice (at least with my
> card installed - WINNOV VIDEUM AV). When I choose either of these, it
> opens up the WINNOV control panel (the card's native software) where i
> can set the capture resolution.

So, don't set it here. Btw, which driver does this Winnow card uses?

> A little further down the VIDEO menu is a CUSTOM CAPTURE RESOLUTION (or
> something similar) choice. Here I can set the capture resolution
> within the VirtualDub program itself.

Set it here. If you can select a capture size here, this size is
supported by your driver (and will be used).

> When I set the custom capture resolution within Virtualdub, the preview
> image does seem to resize itself to the custom resolution specified,
> but I wonder if this is a 'true' capture at this resolution, or merely
> an interpolated re-sizing done by Virtualdub. Which capture resolution
> overrides which? i.e. if I have the WINNOV control panel set up to
> capture 320x240 and from within VirtualDub set the CUSTOM capture
> resolution to 640x480, will the resultant AVI be "truely" 640x480, or
> will the card capture at 320x240 and feed this to Virtualdub, which
> will then do an "upsampling" to 640x480?

No.

Note, the requested capture size is independent of the size at
which your card/driver caps (= sample rate). The sample rate of
your card is much larger than 640x480, and your clip will be downsized
to 640x480 (or to any other size you reguest). More about this can be
found in the cap guide at doom9.org.

Wilbert
!