Virtual Dub: Recompress - keyframe help

[milkydoo]

I've used virtual dub quite a bit but there's still a lot of things I don't know, and now I'm needing to do something a little different with it.

I'm needing to take a divx clip and add keyframes. That is all I want to do. I don't need filtering and I don't need quality or bit rate alterations. I just want more keyframes, but I'm unsure as to whether this process will alter the quality or not.

If I select 'file information' on the source file and choose the exact same codec and bit rate for the conversion, will the quality be the same? And should I choose 'fast' or 'normal' recompress for this operation?

I know there's a zillion virtual dub guides out there, but many seem to be only partial guides. If you have a link to an in depth guide that will really help me master VD, please post it here. Thanks for your help.

[rankz]

Yeh i was told to download that programme. so i did. What does it do?

[VCDHunter]

You won't improve quality by recompressing the video.
Why do you need more keyframes ?

[milkydoo]

You won't improve quality by recompressing the video.
Why do you need more keyframes ?

I don't need to improve the quality, I just need to _maintain_ the quality I've got in the source. I'm just wondering if recompression using the same bitrate would *reduce* the quality any via factors that I'm not aware of.

I need to add keyframes because I have cut out a very short chunk of the source file which was encoded with the default 300 setting for keyframes. My new clip will only be 300 frames long so I won't be able to pause it anywhere in the middle.

[luke2578]

There is a possible solution.

All you have to do is:

1. Go to VirtualDub, select "Open Video File", from the "File" menu and check "Popup Extended Options" at the bottom of the "Open" dialog box. Then open the file you want to sort out.

2. When the new window appears check "Rederive Keyframes". It will automatically check the frame structure of the file. It may take a while to do this, especially if you have an older computer or a large file.

3. As soon as this has finished make sure that "Direct Stream Copy" is selected in both the "Video" and "Audio" menu.

4. Save the file in the "File" menu under the "Save as AVI" option. Give the file a name and hopefully it will work.