VirtualDub Cutting - Keyframe

[ejp]

OK, I'm very new to this board. I just registered a few hours ago. I have a question, and it might've been answered already. But I've searched the forum and I can't find the answer. This is my first post, so here it goes.

When you talk about cutting AVIs, the first thing that comes to your mind is VirtualDub. So that's what I used, and I followed the guide to the letter. I've cut/joined AVIs multiple times. But it seems I've encountered a problem.

I'm trying to cut a particular AVI. I started the beginning mark at 10.010 seconds. This is far before the second Keyframe. There's a Keyframe at frame 0. And I ended the end mark at the last frame.

I saved everything properly. But when I opened the saved file, it wasn't cut at all. The first 10.010 second are still there. It's as if I never cut it, and it's the same exact copy of the original.

I really don't know what's going on, or how to go about fixing this. Maybe someone has an idea or solution. If you do, PLEASE tell me!

Thanks in advance.

[KingJohn]

You deleted a frame, but didn't delete the non-keyframes after it.

A keyframe is a frame that can be decoded on its own; a non-keyframe, or delta frame, is a difference from the previous frame and cannot be decoded if the frame before it is missing. VirtualDub always plays it safe and makes sure that all frames that you don't delete are decodable. This means that any non-keyframe that you include will force inclusion of any frames before it, back to and including the previous keyframe.

Below the position slider and to the right of the motion buttons, there is a timestamp counter that shows the current position:

Notice the [K] at the end -- this is the current frame type. K indicates a keyframe; nothing indicates a delta frame; [D] indicates a dropped frame, which is another type of non-keyframe. Basically, all you have to do is ensure that when you delete a segment, you end the delete right before the next keyframe. You can seek between keyframes by holding SHIFT when dragging the nub or clicking on the forward and backward buttons with the yellow key icon.

[ejp]

So you're saying I can't do anything about this? There's no way around it? You can't put in your own keyframes, or anything like that? Is there another tool that might help? If not, then that's alright. Thanks again, KingJohn.

[KingJohn]

Um... Not with Vdub, some more advanced editing software perhaps like Premier, perhaps the key frames are two wide apart, how far do they jump when you hit the button.

Re-encoding with key frames every 5 will close it down, default is usually every 10, but DivX5 default is every 100

[ejp]

Actually, I have the Adobe Premiere 6 Demo. I just got it a few days ago, so I really don't know how to use it.

I've made a mistake. The entire file is only 10.010 seconds long. There is a keyframe at frame 0, and one at the last frame. I only want to get the video from frame 164 to the last frame. Frame 164 is at 5.472 seconds.

Anyway, how would I go about re-encoding with a specified keyframe rate (if that's what it's called)? That would be perfect. Thanks.

[ejp]

Just a few minutes ago, I was playing around with VirtualDub. I was doing further editing with a music video I've edited already. This music video, I've done some editing wtih it in Adobe Premiere 6. I wanted to crop some of the top off.

So anyway, I opened it up in VirtualDub for the first time after editing it in Premiere. I was going through the video. I realized something. Premiere made EVERY frame a Keyframe!!!

I was kinda confused and surprised at the first time I saw it. But it was real. EVERY frame was a Keyframe.

Now, I'm going to try to open up this 10.010 second video in Premiere, and just save the timeline. But it seems like some quality is lost after saving it. Does anyone have any suggestions as to how to preserve quaility when saving in Premiere? Maybe it's just me. Maybe quality ISN'T lost.

Well, I'll post again if it was successful or not.

[ejp]

OK, well, I've investigated this, and, Yes, Adobe Premiere 6 really does this. But there are a few things to keep in mind. It all lies in the way you export the Movie from the Timeline. When you export them, and you look at the "Settings...", in "General", for "File Type", it must be "Mircrosoft DV AVI". But when you go into the "Video" menu, you can't play around with the "Frame Size". If you keep it that way, it will save the "Frame Size" as 720 x 480, if you're saving it with the "Compressor" as "Microsoft DV (NTSC)".

So I went back to the "General" menu, and I changed the "File Type" to "Microsoft AVI". Now, in the "Video" menu, there's many more "Compressors". I chose "DivX MPEG-4 Fast-Motion". You can "Configure" it so that it "Keyframes" whenever (ie: every 10 seconds). But 5.474 seconds is NOT an even second; you have decimals in there. But you can still set the "Frame Size" to whatever you want. I saved it, and opened it up in VirtualDub, and sure enough, there was a Keyframe at the 10th second, because that's what I set it to.

So, what I did was, I saved it with ALL frames being a Keyframe, and the "Frame Size" wrong. I cut the movie from the 5.474th second (which is what I want), and I ended it at the last frame. I saved that, and I opened it up in Premiere. And I saved the Movie from the Timeline as "Microsoft AVI", so that I can change the "Frame Size" back to normal (544 x 400). Sure enough, it worked.

But SO MUCH quality was lost. And I did this without sound. So I don't even want to start thinking about how terrible the sound would be. Any ideas how to fix this?

[KingJohn]

Well the question was adding more frames, but Vdub can save out the AVI in full processing mode, then selecting a codec to match you can also specify the interval of key frames.

DivX Low motion, key frames every 5, bit rate 300(lower if source is good)

[ejp]

OK, I did all that you said to do. After awhile, I finally got it. But I have another problem.

You said to make the bit rate 300. But I viewed it, and it looked a little blury. So I played around with it, and the quality got better as I set the bit rate higher.

So I was wondering if there was a mathimatical, or SOME way, to determine the exact bit rate to set.

If there is, then I would be very greatful. If there isn't, then I'll just play around with it until I see something I like. Thanks.

[KingJohn]

There is a calculator to work out the final size, don't know if that's what you mean. The 300 was a starting point as I have used that with DVD rips and that figure was fine. But you have already found out the higher the number the better the quality, the larger the size.