Virtualdub or Virtualdubmod for DV AVI trimming?

[sasuweh]

I have several DV AVI captures I made from VHS tapes, and I would like to load them into Virtualdub to trim the beginning and end of each video. Is it recommended to use Virtualdub or Virtualdubmod, or does it matter?

Elsewhere on this site I found this comment:

"Experience of many people on this site is that, although VirtualDub will do the job nicely on the video, it spits its dummy out at VBR audio and doesn't give you the option to tell it to ignore it. End result - out of synch audio.

But there's an alternative: VirtualDubMod."

but that comment was in regards to a divx file with vbr mp3 audio. I'm dealing with DV AVI and PCM audio, so would it not matter which I use?

[Baldrick]

Avisynth makes it to yuv. You have to open it directly in virtualdub.

[sasuweh]

Okay, thank you very much - I got it solved now. It won't play the video if I open it directly but it will open it and save it.

So I guess I don't need to use Virtualdubmod for trimming?

[jagabo]

VirtualDub should work fine. But it may have problems if your VFW DV decoder is putting out YUY2 instead of RGB (VirtualDubMod has the same problem). You can enable RGB output in your VFW decoder or use VirtualDub's internal DV decoder if all you plan on doing is cut/paste editing of DV in Direct Stream Copy mode. Don't use AviSynth -- it will decompress frames so you'll be reencoding your video.

[sasuweh]

Okay, I think I'm learning here. I found something you said a while back elsewhere on this forum:

"DV is YUV internally. The question is what does the DV decoder output. As you've seen Cedocida can output YUV or RGB. You can force it to use one or the other, or to negotiate with the editor for what the editor prefers. Panasonic DV Codec, in addtion to several bugs) only outputs RGB and only after a contrast expansion that loses blacks below IRE 0 and brights above IRE 100. Microsoft's DV decoder can output either YUV or RGB -- whichever the editor prefers.

If VirtualDub receives YUV from the DV decoder (or is using its internal DV decoder) the same loss of blacks and brights will occur when it converts to RGB for filtering. Having Cedocida do the conversion to RGB lets you specify whether that contrast expansion should occur.

This problem comes about because in YUV video black is at Y=16 and full bright at Y=235. But on computers black is RGB=0 and white at RGB=255. So most programs stretch the contrast from Y=16-235 to RGB=0-255. They will then compress the range on conversion back to YUV."


So following that I went into Cedocida and changed the ouput from YUY2 (which I use when decoding for CCE) to RGB. Now the AVIs play in Virtualdub. But 2 other quick questions and I think I'll be all set:

1) Do I set the Cedocida decoder output to RGB24 or RGB32 for Virtualdub? I don't know which one Virtualdub uses. Isn't RGB24 slower to process than RGB32?

2) I think the Cedocida decoder should be set at 0..255>0.255 correct? And do I need to worry about the Encoder settings on the top if I'm just using Virtualdub for Direct Stream copy?

So here's what Cedocida looks like now. Should anything here be changed?

[jagabo]

1) Do I set the Cedocida decoder output to RGB24 or RGB32 for Virtualdub? I don't know which one Virtualdub uses.

I think RGB32, but I don't remember for sure. Maybe both.

2) I think the Cedocida decoder should be set at 0..255>0.255 correct? And do I need to worry about the Encoder settings on the top if I'm just using Virtualdub for Direct Stream copy?

It doesn't matter what you have it set to for Direct Stream Copy cut/paste editing. The decompression and conversion is only used to show you the picture in VirtualDub. The video frames themselves pass from the input file to the output file without any changes, no decompression or compression. 16-235 -> 0-255 will look correct on the computer monitor.

[sasuweh]

Just noticed I was still adding to my last post as you were answering. Okay, my screenshot above is what it looks like right now. Since I'm just doing a direct stream copy I should be all set then. Now I can actually play the video in virtualdub while I'm setting the trim marks. Any difference if I set encoder quality to normal or fast?

[poisondeathray]

Any difference if I set encoder quality to normal or fast?

No, because you're not using the encoder when you have it set to direct stream copy and making cuts

[sasuweh]

Thanks again!