Splitting and Rejoining Video Segments with Virtualdub

[unclescoob]

Hi folks,

I am currently working on a video that requires different filters in different scenes (using Virtualdub for this project). For this reason, I have split the episode into segments and applied the filters to each segment accordingly. My plan is to then rejoin the saved AVI segments with Virtualdub. No problem so far.

Here's my concern:

I understand that loading a video with Virtualdub and saving it as an AVI does not result in loss of quality, as it is uncompressed (using Huffyuv). When I take my saved AVI segments, reload them into Virtualdub (for the purpose of joining them), and save them again as a new AVI, would I THEN begin to lose quality? If it is true uncompressed, then I assume the answer is no. However, I am aiming for professional results and want to make sure I'm not missing something.

Thanks in advance

[redwudz]

I understand that loading a video with Virtualdub and saving it as an AVI
does not result in loss of quality, as it is uncompressed (using Huffyuv).

I've never had that understanding.
If you set it as encoded with HuffyUV, then that might be so. Default is RGB, quite a different codec.

But if you save the filtered file as an uncompressed video, HuffyUV or Lagarith, then they should retain their quality.

Of course if you re-encode to another format, you would have quality loss. That would mostly depend on the conversion format you use. But using a lossless format should keep the quality until you re-encode.

[Gavino]

I am currently working on a video that requires different filters in different scenes (using Virtualdub for this project). For this reason, I have split the episode into segments and applied the filters to each segment accordingly. My plan is to then rejoin the saved AVI segments with Virtualdub.

Instead of splitting the video into segments, you can use filter curves to apply the filters only to specific parts of the video. See "filter curves" in the VDub help file.

[unclescoob]

Gavino, my eyes must be giving out on me or something. Can't find the subject at all in the link you gave, unless I'm missing something! I have VirtualdubMPeg2. Could you please sort of guide me on where I should go in Virtualdub in order to find filter curves?

I appreciate it.

[Gavino]

I don't know about VirtualDubMpeg2 (isn't that based on a very old version of VirtualDub?), but in the 'real' VirtualDub, you activate the feature for a given filter by clicking on 'Blend' in the Video Filters dialog. To select the frames for which you want to apply the filter, go to View->Curve Editor - set the opacity to 100% where you want the filter and 0% elsewhere.

In the Help, it is described in the section Processing->Video Filters->Filter Curves.