Replacing last 5 minutes in mkv video

[carlmart]

I have the following issue: the last five minutes in an mkv video I captured has some errors which I can't repair.

It's mostly titles and music, but in the middle there's a video image on the side, with image and audio.

I do have the DVD for this film, but it's in the wrong fps: the DVD is 29.97 and the mkv in 25,

So I have to convert frame rate, remove deinterlace and if possible add some slight enhancement.

The simplest way I can think of is using VirtualDub. But on a test I just made the file became HUGE for just 5 minutes. Largest than the whole MKV file!

So in what order should I do things and how can I keep files small?

[davexnet]

Possible Virtualdub beginners mistake? Forgot to set a video compression codec ?

Then it defaults to uncompressed = massive

[awgie]

If you have the DVD, you may find it much quicker, easier, and better quality to go back and re-rip the DVD and use that.

[carlmart]

Yes, using the DVD is what I'm trying to do now.

But the steps I mentioned still have to be taken: convert to 25fps, convert to 1280:720 mkv, deinterlace, enhance. edit into mkv file.

[awgie]

So is the MKV made up from more than one source? I understood from your original post that it was a single video, but maybe I misunderstood.

[carlmart]

Yes, the main MKV file, which I want to change the tail on, is a single video.

There are some glitches in the last five minutes which I can't repair, so I'm looking at ways to mend it somehow.

I have a DVD for the whole film, which is unfortunately lower in quality, as a DVD is supposed to be.

The sequence I want to use is intact though, so I should have to do all the steps I described.

I got a program called Wondershare Video Converter, which will convert the DVD excerpt to MKV at 25fps. I don't know if it deinterlaces the video and it doesn't have enhance capabilities. That's why I tried enhancing the file with Virtualdub first.

[awgie]

So if you perform all those steps on just the last five minutes, you will still have a noticeable change in quality at that point in the film, mainly because you are converting from 29.97 to 25 fps. That issue alone would be enough to make me want to start all over using the DVD and do the entire film, leaving it at 29.97 fps. I have never been particularly happy with the results when I've had to convert from one frame rate to another.

The rest of the film may end up at a slightly lesser quality if you redo the whole thing, but will it really be enough to bother you? Only you can answer that. I, for one, would be more bothered by the sudden change at that last five minutes if you were to only use the DVD for that segment.

[carlmart]

You can't compare the quality from the 720P version and the DVD.

It's alright to do it for the final titles, but certainly not for the rest of the movie.

I can live with the change in quality on the final titles, but I still would like to know how much I can improve on what I have.

My experience converting 29.97 to 25fps or the opposite has been as bad as yours apparently. In fact it has been quite good.

Of course that images have to be rather static, it wouldn't work with fast stuff.

In this case it's rolling subtitles, so I would like to cheat a bit to increase apparent resolution.

This is something I have to do, so what I'm looking is for the best compromise to get it done. Particularly on filters to use.

[davexnet]

Why don't you post 15 - 20 seconds of the footage that demonstrates the problem, then perhaps you'll
get more specific advice

[jagabo]

Converting 29.97 fps to 25 fps won't reduce the quality if done right (aside from the reencoding, of course). You just need to inverse telecine to 23.976 fps then speed up to 25 fps. In AviSynth that can be as simple as

Mpeg2Source()
TFM()
TDecimate()
AssumeFPS(25)

You'll have to speed up the audio by about 4 percent too.

[carlmart]

Possible Virtualdub beginners mistake? Forgot to set a video compression codec ?

Then it defaults to uncompressed = massive

Messing things in VD apparently. Very little experience with it, and the one I had I forgot. Same thing with Avisynth.

1) Which compression to pick and how to set it up?

2) Just tried another job, enhancing a 97-minutes video, and it shows 14-hour processing. How to speed up things with VD?

[davexnet]

The speed depends on the specification of your PC, the resolution of the file(s) and the filters being used.

Perhaps use a lossless intermediate like Lagarith, and then convert to your final format later (Presumably to match
up with the rest of your MKV. Many ways to approach this)