Scene detection im MPEG2 files?

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
3 answers Last reply
More about scene detection mpeg2 files
  1. 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.
  2. 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
  3. 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
    Posted with XanaNews Version 1.16.3.1
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