AVI Trim

[drgt]

I have a xvid avi with ac3 audio and I want to cut off a few minutes at the end thinking it will reduce its size which is now 1.6 gb.

1. If I keep the same video & audio codecs, is this easy to do or does it have to be re-encoded from scratch (in which case I might end up with a larger file instead of smaller).

2. Would virtualdub do it? Does it support AC3?

[poisondeathray]

Yes you can do it in vdub

install ac3acm

in vdub, set video=>direct stream copy , audio=> direct stream copy to prevent it from re-encoding

[drgt]

Thanks.

I thought I had to use "Smart rendering" under video to prevent it from re-encoding...

What is "Smart rendering" used for?

[manono]

Smart rendering is used when you're cutting in the middle of a GOP. It allows for frame-specific cuts and only reencodes the part to the next I-Frame. That probably doesn't matter to you and cutting on an I-Frame also allows for no reencoding and doesn't require the use of smart rendering.

[drgt]

Ooops! I need to do some reading! I have no idea what GOP and I-Frame are!

Nevertheless, I got the message that this does not apply to what I want to do BUT in reading it, it sounds:
"Use smart rendering to cut on an I-Frame,
Cutting on an I-Frame does not require the use of smart rendering"

Contradictory, or this is "one way equation"?

[manono]

Not at all contradictory. You just don't understand what you're reading. If you need frame-specific cutting, you need smart rendering. If it's OK to cut on an I-Frame, you don't need smart rendering, Typically, for AVIs I-Frames (aka Keyframes) are found every ten seconds. If that kind of a split is OK for you (and from what I can gather, it is), you need neither smart rendering nor any reencoding at all. Just set everything for Direct Stream Copy, set your cut points (scrolling with the shift key held down will have you stop only on I-Frames), and save.

[drgt]

Got it! (I think...)

Thanks all of you!!!!