Newbie: Easy program for EXACTLY cutting AVI/MPG files?

[jeffonthego]

Have tried Nanddub/Virtualdub to cut an AVI file.

However, I find that the splicing is off by as much as 5 seconds from the point I specified. I'm very meticulous about finding exact point I want, yet the programs seems to not be so precise. Seems to me I've read others mention this problem.

Is there a program or a way with these programs to do exact splices of a file?

Thanks,
Jeff

[mkelley]

Sure, any decent video editor will do exactly what you want.

Microsoft Movie Maker is probably the easiest, and free if you have XP. But I do all my editing in Premiere (pricey and worth every penny). Premiere is also easy to learn if all you want to do is simple edits (but Vegas Video also gets good press).

[Paul_W]

I would agree with mkelly's advice. Download the free trail of Premier and give it a try. At least you'll be able to complet the project that you are currently working on.

[thayne]

For mpeg Womble MpegVcr is awesome, very precise and easy to use, but it's not cheap....

[housepig]

Jeff -

if you are cutting with Virtualdub and it's not cutting where you want, you are probably not cutting on a key frame, and it's going to the next nearest keyframe and cutting there.

at the bottom of Virtualdub's window, you should see a frame number - if you don't have a (K) next to it, your cut isn't going to be clean. You can hit the Next Keyframe button and go to the next nearest keyframe, or the Previous Keyframe button and see the last cut point.

If you are trying to do exact, pinpoint editing on a file and it doesn't have enough keyframes (like a highly compressed divx file or something) you may have to blow it up into a less compressed form to get the accuracy you need.

[jeffonthego]

Housepig, the keyframe sounds like my problem - ie, it's splicing at keyframes rather than exact point I try to offset it for. What I'm not clear on is how to get it to recognize a specific point other than a keyframe. If it's not an imposition, would you mind laying out the steps I need to follow to do this? Appreciate your help.

As for everyone else, thanks for your replies, will try to hook up and try out some of the programs suggested.

[housepig]

Jeff -

what you need is a file with more keyframes in it. what I would do would be to recompress the file with a lower-compression codec, like Huffyuv or something similar.

this will give you more keyframes to work with.

if you are hard-up for disc space, though, or really concerned with quality and you don't want to recompress, here's a really labor intensive way to do it.

let's say these are your key frames:

1---2---3---4---5---6---7

you want to cut at about 3.5. go to where you want to cut, go back 1 keyframe and cut there, so you end up with

1---2---3

save as a new file. open the original again. cut everything before keyframe 3 and after keyframe 4, so you get

3---4

save as a new file. open that file, save it with a less-compressed codec. so what you'll get will be

3abcdef4 (where abcdef are 6 new keyframes placed by the new codec).

now cut from 3 to 3c. save as a new file, compressing back with the original codec.

Join them all together. precise cut, a horky workaround but not a huge waste of time and space.

this looks really kludgy, I know, but if you use Virtualdub it shouldn't take that much time.

[jeffonthego]

Thanks Housepig. May give it a try, though I have to admit that it sounds like a headache. Think I'll try get my hands on of the other programs suggested. I never realised doing a simple, yet precise, splice of a video could be so complicated!

[housepig]

I have to admit that it sounds like a headache.

you're quite right. I'll say two things:

1. it's really not as bad as it looks, at least after you've done it once or twice.

2. if you can find another program that works for you, rock on. this is more of a "last resort".

my thing is, I usually know if I'm going to have to edit something, so I capture it in such a way that the edit is going to be easy - I usually am not editing anything I haven't captured myself.

[Zak0]

The one thing I haven't seen explained here yet is WHY you can only cut on keyframes. I assume it's because they're the only COMPLETE frames in the stream, right? Anything that isn't a keyframe contains only the differences between it and the previous frame or something, I think. Maybe someone else can explain this better - just thought it was an important note to add to this conversation.

-Zak

[lordsmurf]

For MPEG1/MPEG2, I use TMPGEnc Plus or Womble MPEG2VCR

[housepig]

I assume it's because they're the only COMPLETE frames in the stream, right? Anything that isn't a keyframe contains only the differences between it and the previous frame or something, I think.

that's the way I understand it...

[jeffonthego]

Thanks again guys.

Do appreciate that suggestion Housepig, have filed it away for when I have more time to play around with the file or as a last resort.

Thanks Zak0 for adding the explanation, though I'm still not quite clear and what is a "complete frame". But I'm pretty new at all this . . .[/quote]

[housepig]

Jeff -

here's how it works (super basic version).

you have a keyframe - it's a full image of everything on the screen.

in between this frame and the next keyframe are frames that do not contain the full image, they only contain a set of data of the difference between this keyframe and the next.

generally, the more you compress, the fewer keyframes you have (they take up a lot more space than a difference-data frame).

[jeffonthego]

Oh ok, I see. Put that way, it becomes clearer why programs might not be able to cut in between complete frames. Thanks for that.

[Beavis]

Some MPEG editors are smart enough to allow you to cut on any frame you want and then it will re-encode that cut (and only that cut) so that the final product is exactly what you want. Lots of people complain about audio-sync problems when doing that, but I've had good luck with Ulead Video Studio 6. Best thing, however is to edit an AVI where all frames are keyframes and then encode afterwards, but that's not always possible or convenient.