Editing MPEG2 files - are they re-compressed every time?

[James]

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

I am working on home movies (purely for the family - unprofessional,
etc.)

If I capture and save as MPEG2 - like save large chunks of video off of
a tape, and I go back later and "chop" it up into scenes, does the
video get re-compressed?

I know if I open up a JPEG picture, make the tiniest of changes, and
re-save, it re-compresses and makes the image worse.

For my MPEG's, all I'll be doing is chopping footage off the front &
back, and re-saving as MPEG2.

Thank you for your assistance.

 

[Guest]

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

"james" wrote ...
>I am working on home movies (purely for the family - unprofessional,
> etc.)
>
> If I capture and save as MPEG2 - like save large chunks of video off
> of
> a tape, and I go back later and "chop" it up into scenes, does the
> video get re-compressed?

Depends on what you are using to edit. If you cut only at an
I-frame and are using software optimized for editing MPEG,
then no it does not get re-compressed. Otherwise, some (or
possibly ALL) of the video gets re-compressed. That is the
major difference between spatially-compressed formats like
DV and M-JPEG, and temporally-compressed formats like
MPEG. Many of us still don't consider MPEG to be anything
but a release format which is not suitable for editing.

>
> I know if I open up a JPEG picture, make the tiniest of changes, and
> re-save, it re-compresses and makes the image worse.
>
> For my MPEG's, all I'll be doing is chopping footage off the front &
> back, and re-saving as MPEG2.

If you use a MPEG edit software that preserves the compression,
you'll likely be OK.

 

[Guest]

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

"james" <kevlar9296@aol.com> wrote in message
news:1123814562.973234.277680@g47g2000cwa.googlegroups.com...
>I am working on home movies (purely for the family - unprofessional,
> etc.)
>
> If I capture and save as MPEG2 - like save large chunks of video off of
> a tape, and I go back later and "chop" it up into scenes, does the
> video get re-compressed?
>
> I know if I open up a JPEG picture, make the tiniest of changes, and
> re-save, it re-compresses and makes the image worse.
>
> For my MPEG's, all I'll be doing is chopping footage off the front &
> back, and re-saving as MPEG2.
>
> Thank you for your assistance.
>

There is no need to re-encode if you are just cutting and/or
joining MPEG. For that sort of thing I like VideoReDo.
www.VideoReDo.com There are even full featured Editors
that can do smart rendering, that is they only re-encode the
minimum number of GOP need to effect the changes you
have made. A couple of GOP for a transition for instance.
The rest of the MPEG is just copied over, having no effect
on your video. Just remember the more bells and whistles
a piece of software has the more you have to learn, to be
able to use it.

www.videohelp.com search their listings for MPEG Editors.

Luck;
Ken

 

[Guest]

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

"Richard Crowley" <rcrowley@xpr7t.net> wrote in message
news:11fo9bfgflg6o6a@corp.supernews.com...

> MPEG. Many of us still don't consider MPEG to be anything
> but a release format which is not suitable for editing.


I want a T-Shirt with that on it.

 

[Guest]

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

"Jona Vark" <noemail@all.com> wrote in message
news:Os3Le.990$SR5.904@newssvr22.news.prodigy.net...
>
> "Richard Crowley" <rcrowley@xpr7t.net> wrote in message
> news:11fo9bfgflg6o6a@corp.supernews.com...
>
>> MPEG. Many of us still don't consider MPEG to be anything
>> but a release format which is not suitable for editing.
>
>
> I want a T-Shirt with that on it.
>

If Richard is out of them, try PTravel he might have a few.

LOL;
Ken