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Scene detection im MPEG2 files?

Last response: in Graphics & Displays
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Anonymous
July 30, 2004 3:01:29 PM

Archived from groups: uk.rec.video.digital,rec.video.production,rec.video.desktop,rec.video.dvd.tech,alt.video.dvd.authoring (More info?)

I use Ulead VideoStudio to capture and edit video from my DV camcorder.
However, the MPEG2 encoding is not very good, so I export the edited video
as an AVI file and convert it into MPEG2 using TMPGEnc Xpress. The results
are much better (even though it takes much longer).

The problem is when I return the file to VideoStudio to make the DVD. The
wizard that handles the making of the menu does not see any seen changes. By
comparison, if I render the video into MPEG2 using VideoStudio and save it
to a file, the wizard does see the scene changes.

In summary, TMPGenc Xpress is not placing "marks" in the MGEG2 files for
scene automatic scene detection whereas the VideoStudio internal encoder
seems to do things differently.

Can anybody shed any light on what might be happening? Is there any way to
post process an MGEG2 file to insert scene-detection "marks" that the
VideoStudio wizard might recognise?

Thanks,

Raymond
Anonymous
July 31, 2004 5:18:46 PM

Archived from groups: uk.rec.video.digital,rec.video.production,rec.video.desktop,rec.video.dvd.tech,alt.video.dvd.authoring (More info?)

In article <ced65r$gf4$1@south.jnrs.ja.net>,
ray@le.ac.uk says...
> I use Ulead VideoStudio to capture and edit video from my DV camcorder.
> However, the MPEG2 encoding is not very good, so I export the edited video
> as an AVI file and convert it into MPEG2 using TMPGEnc Xpress. The results
> are much better (even though it takes much longer).
>
> The problem is when I return the file to VideoStudio to make the DVD. The
> wizard that handles the making of the menu does not see any seen changes. By
> comparison, if I render the video into MPEG2 using VideoStudio and save it
> to a file, the wizard does see the scene changes.
>
> In summary, TMPGenc Xpress is not placing "marks" in the MGEG2 files for
> scene automatic scene detection whereas the VideoStudio internal encoder
> seems to do things differently.
>
> Can anybody shed any light on what might be happening? Is there any way to
> post process an MGEG2 file to insert scene-detection "marks" that the
> VideoStudio wizard might recognise?
>

I'll take a guess...

DV files have built-in timecodes for each frame in the
video. VideoStudio is looking for places where the
timecode suddenly changes, which to it, indicates a
"scene change". And when VS renders the MPEG2 output,
perhaps it's also writing a "hint" file indicating where
the scene changes are?

MPEG2 doesn't have timecodes or "marks" AFAIK. Or at
least, the conversion process going from DV to MPEG2 in
TMPEnc will trash the existing DV timecodes.

What you might want to do is when converting from DV to
MPEG2, create separate MPEG2 files for each
scene/chapter rather then creating one large MPEG2 file.
August 1, 2004 2:41:44 AM

Archived from groups: uk.rec.video.digital,rec.video.production,rec.video.desktop,rec.video.dvd.tech,alt.video.dvd.authoring (More info?)

"Raymond Dalgleish" <ray@le.ac.uk> wrote in message
news:ced65r$gf4$1@south.jnrs.ja.net...
> I use Ulead VideoStudio to capture and edit video from my DV camcorder.
> However, the MPEG2 encoding is not very good,

What aspects of it enable you to come to that conclusion?
I ask because I too use the Ulead package. Some of my captures from the
camcorder look ok, but others from s-video tv source looked as if they had
originated from poor composite video, hard to describe but a sort of halo effect
round all the shapes.

Roger
Anonymous
August 1, 2004 2:43:03 AM

Archived from groups: uk.rec.video.digital,rec.video.production,rec.video.desktop,rec.video.dvd.tech,alt.video.dvd.authoring (More info?)

oN 07/31/04, Toshi1873 said:

> MPEG2 doesn't have timecodes or "marks" AFAIK. Or at
> least, the conversion process going from DV to MPEG2 in
> TMPEnc will trash the existing DV timecodes.

MPEG2 does have timestamps; 33 bit numbers taken from a 90KHz clock.

--
Bill
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