Correlation

[blackion]

I have recently used virtualdub to cut unwanted parts of a .AVI file. Then I tried to save it with "fast recompress" while enabling smart rendering (because I cut on frame basis).

It would proceed saving up to 40% and then it would become stuck.

I have tried different ways and the only way it has saved the file was via "full recompress". Obviously the quality of the video has deteriorated. (I couldnt save as uncompressed due to the file would become huge.)

Is there any way to use the resulting file's video or audio streams in order to automatically cut the original file and get it saved via smart rendering (so that only the frames that need recompressing will be recompressed).

(And I have actually repeated this tedious work of trying to cut this movie again, however again all versions of vdub would stuck in 40%. I don't have this problem with other video files.)

[mammo1789]

The files are not AVI s because they are containers (meaning contains different codecs like MJPEG,DIVX lagarith or else)If you want to only join two files together or "cut unwanted parts" you can do it faster in vdub using direct copy for video and audio with no quality loss.

[Cornucopia]

Don't know what that other guy was getting at: Virtualdub mainly works with AVI as input (other plugin options available), and ONLY AVI as output. AVI can contain many different kinds of codecs.
We don't yet know what codec you used...
If you are just CUTTING, and it is on I-frame boundaries, you can use DirectStreamCopy. If it's not on I-frame boundaries (even though you say you are), "smart rendering" is only available for certain codecs and only if you have avoided processing. If you have processed or used other than those few codecs, you will have to do a full recompress regardless.
Now, at that point, what bitrate & other settings you use will be a greater determiner of quality than just the fact that you had to do a full recompress.

When cutting with Vdub, I STRONGLY recommend you do your cuts in 1 pass, while exporting to Lossless AVI (lagarith, etc). Then re-import and process & export to desired compression. Yes, it will have a large intermediate file. Big whoop - large drive space is a dime a dozen these days.

Scott

[blackion]

I think my question was misunderstood. I'm aware of the codecs. XVID and Mp3 were contained in .avi.

The problem is that I have already cut it. But as you know, in virtualdub I cannot save "project". So when it got failed to save AVI with fast recompress and smart rendering, I saved with with full recompress. I did notice quality drop.
So I would like to automatically re-cut the original file using the video stream or the audio streams as the reference.

[jagabo]

You should try Smart Rendering in Full Processing mode. VirtualDub's pretty smart about that now and won't convert colorspaces in full processing mode unless you use a filter that requires it. But it sounds like there is a problem in your source file that's causing VirtualDub to hang.

[blackion]

Are you sure? I read the manual and it was written there that smart rendering should be used with fast recompress.
But anyway, is there a way to correlate it?

And, if there is an error in the avi, how can I check/fix it?

[jagabo]

You can try Video -> Scan Video Stream For Errors. But I find that hardly ever works in cases like this.

Since the program hangs 40 percent into a conversion you can try putting the cursor a little before that and previewing the video. If it hangs while previewing you'll know exactly where the problem is. Cut out that section from the keyframe just before it and the keyframe just after it (hold down a Shift key while navigating so you'll only stop on keyframes). Then work with the rest of the video as you did before.

[blackion]

Yes, Scan video didn't show anything. But isn't there any tool that will do that automatically, ei scan for errors and cut out/fix the section?

2. Are you confident that previewing will stop at the problematic frame? I used to preview here and there, I don't remember it ever hanged. (And it did save the video in full recompress, indicating that reading wasn't a problem?)

Thanks

[jagabo]

Yes, Scan video didn't show anything. But isn't there any tool that will do that automatically, ei scan for errors and cut out/fix the section?

Not that I know of. You might try running it through DivFix++.

2. Are you confident that previewing will stop at the problematic frame?

No.

And it did save the video in full recompress, indicating that reading wasn't a problem?

Yes, that sounds like VirtualDub had no problems reading the source file. But sometimes you get buts that show up under one situation but not another similar situation. For example, you might have a problem when you do A, B and C. But not when you do A and B, or B and C, or A and C. All I can suggest is you try variations on what you have done in the past. Use a different decoder, a different encoder, different modes in VirtualDub.

Another thing you might try: remux the video with VirtualDub or AviDemux. Then edit the new AVI.