retaining quality of video after multiple editing processes....

[Questmark]

Hi,
First, I just wanted to say how helpful these boards have been. You guys are awesome. Now, my question--

I'm attempting to edit 4 ogm files together, and to burn them onto a DVD. I demuxed them into avi, wav, and srt files. Now, I decided I wanted to edit them together, not just make cuts of sections (like VDubMod can do), but to actually crossfade the sound from the end of some of avi's onto the beginning of the next, to make it feel more seemless. I dl'ed the trial version of Vegas 6.0, studied the program a lot, and have been able to trim and cross fade everything I wanted in the program. However, the ogm's have selectable subs, and since I was crossfading the audio and video of different files, it seemed to me that I would have to save the two combined avi and wav files as new, larger avi and wav files after editing in Vegas. This led me to be concerend that I would lose the timing on the subs, as the avi's would no longer be the same length as the ogms (say 23 mins or so), but instead would be the combination of 2-4 of the avi's (40-80 mins). SO, I decided to hardsub the subs onto the demuxed avi's that I had made before importing them to Vegas.

All of this has led, at this point, to 1) a very large file (10.3 GB) for about 48 minutes of video, and 2) a distinct reduction in the quality of the picture, as I have already taken an ogm, demuxed it into an avi, hardsubbed the subs onto it (rather than using vobsub, since I was editing the files together), and then resaved the combined avi files as a new, larger avi file. I am concerened that once I encode them to M2v that quality will get even worse. :igh:: Besides which, 20GB for an 80 min video is ridiculously large. What have I done wrong here? I feel like there must be a simpler way to do this that also gives me better video quality.

I'm thinking-- if I have the DVD and burnt it direct to mpegs and then was somehow able to edit it there, without converting it to avi, that I would be skipping some steps that would help the quality of the video not degrade. OR, that perhaps I didn't need to make the subs hardsubs, and could have skipped that process, but since I'm crossfading the avi and wav files that didn't seem like an option.

Anyways, I'm sort stuck here and can't figure out what to do. I would like to get a video with a much smaller GB size (as I should be able to put this 80 mins on a DVD) that has much better quality. I mean, the ogms aren't perfect or anything (and perhaps that's why I should burn this direct from the DVD?), but they are distinctly better than what I just watched after rendering the file in Vegas.

Thanks for your help.

[Baldrick]

how did you hardsub? virtualdubmod? what video codec are you using? if you use huffyuv or similiar it will be huge but you wont lose that much quality.

[Questmark]

I hardsubbed using VDubMod, using the tutorial you have up here on videohelp, where you use the textsub filter, compress it (I used the Divx Mpeg4 Fast Motion codec-- there were so many to choose from, I wasn't sure which would be best for what I was doing), and save it with full processing.

If I use the huffyuv codec, the avi will be bigger, which doesn't seem so much of a problem-- the size of the avi's after I hardsubbed them didn't seem to be the problem, in fact they seem to have shrunk (because of the compression and quality loss??)-- thus, a hardsubbed video the size of the original video seems like a reasonable deal. Also, when you say the file will be "huge" if I use huffyuv, what does that mean to you? The original demuxed avi's are about 250MB.

I guess the file size issue has something to do with Vegas?? I mean, Does anyone have any thoughts on that? I'm putting in four hardsubbed avi's of about 100MB apiece, and four wavs of about 250MB a piece, and coming up with a 10 GB video file for only the first half of the project!

[mikiem]

If you've got srt files, why not join & set timing in Subtitle Workshop and author conventional DVD sub track? Or DL trial of DVDA and import your subs as MAC DVD Studio Pro (saveas in S/Workshp) and time there.

RE: file sizes, mjpeg avi's usually run around 30 or so gig I think for a 1.5 - 1.75 hr movie. Might try frame-serveing to avoid the middle re-encode, which will save space & also boost quality. But If you go with text subs, that leaves out v/dub so you're back with everything on the Vegas timeline as you originally wanted.

[Questmark]

Mikiem,
Ok, so you're offering two different options, right? One is to simply retime the subs in Subtitle Workshop and one is to hardsub the current subs using frameserving, right?

I'm not against learning how to use Subtitle Workshop, if it's the best option. I guess I was just hoping to use the timing that the srt subs already have, just so it would be easier. Is Subtitle Workshop very user friendly?

Re: frameserving-- ah ha!! So that's why you frameserve!! To skip a step of encoding and keep the quality up, right? Makes sense. Have to learn that one too I guess.

I was a little confused though, by your comment that:

But If you go with text subs, that leaves out v/dub so you're back with everything on the Vegas timeline as you originally wanted.

I thought if I use textsubs that I have to use v/dub to do that through the filters. You're talking about hardsubbing here right? I guess I'm a little confushed-- if I hardsub and framserve, I can only do that if I'm encoding the avi's to mpegs, right? I've only heard people referencing frameserving if they're, for example, encoding in tmpgenc. Can I frameserve to Vegas? I guess I thought frameserving wasn't an option if I wanted to edit the videos in Vegas.

Could you explain yourself again? It sounded like you had a solution, but I'm not able to catch it.

[guns1inger]

You can't frameserve directly from vdub to vegas, however Link2 will apparently bridge the gap for you.

If you use any form of compression when creating intermediate files, you will reduce quality. You are also falling into the mistake of comparing file sizes. Size means nothing, running time is everything.

At a guess, you have created a DV AVI file when outputing from Vegas. This would explain the increase in size, and the appaprent loss of quality, as it will have resized to D1 res as well.

Do some reading on different codecs, on bitrates, and on the software you are using. It will help a lot if you understand why things work as well as how they work.

[mikiem]

"I was a little confused though, by your comment that:
Quote:
But If you go with text subs, that leaves out v/dub so you're back with everything on the Vegas timeline as you originally wanted."

The way I read it anyway, originally you had everything in Vegas and were doing your editing when you decided to go to v/dub for hard subs. If you use the srt text files to make DVD subs instead of hard subs, maybe you could just pick up where you left off editing in Vegas.
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Srt sub files are just text with time notations. If you've got 3 srt files, normally what I've done is join them in Subtitletool (can use other programs -- just like the interface for joining them there). For timing I usually pad the start of the added srt files to make it easier to find because of the larger gap. At any rate, the relative timing for the added srt file is maintained -- just shift all the times back & forth.

Then Subtitle workshop or DVDA let you play the video with the subs so you can set the correct timing where you joined the srt file. DVDA might be a little easier because you're just dragging an event on a timeline. Again there's probably other tools that work just as well, & I've also just watched the video play or gotten the time from Vegas when the 1st caption from the added sub should play and used that in Subtitletool.

You can import the result into some authoring programs & they'll render a [switchable] graphical sub track that plays with the DVD, or in the tools section you'll find programs that will render the text subs to graphical sup files to be used by programs like muxman.
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RE: frameserving -- I'm very far from expert, but it makes sense to look into it if you wanted to use more then one program working with video files that are already pretty compressed. Very much simplified, one program rather then rendering it's output just sends it on to the next program.

If you decided to go for hard subs, or had any reason to go from one program to the next, frameserving would eliminate having to worry about intermediate files. But that's only if you decide you have a reason to frame serve.

TO go from V/dub to Vegas might seem a bit of a hack, but if you follow this: http://forum.doom9.org/showthread.php?s=&threadid=47483 it seems to work.

[Nelson37]

I would say changing the timing would be fairly easy in Subtitle Workshop, but do it in sections. Example - Section 1, runtime 20 minutes. No changes. Section 2 - load seperately, add 20 minutes plus whatever seconds for the crossfade to the initial time, adjust timings, then copy to the end of Section 1, continue. Section three would add the total time of section 1 and section 2, plus fade. Not too bad. Also I just dislike hard-coded subs.

On the quality problem - EVERY time you convert, you lose quality. Unless it is to a Huffy or Uncompressed AVI. You must take care to NOT convert the file in any way until you are done and are ready for final output. As stated, ignore filesize except as it indicates compression type used. Your stated filesizes are actually about half what a Huffy AVI typically runs, nowhere near ridiculous.

Now, you describe about 8 processes and then state quality sucks after all that. Need to know about quality after process 1, and 2, and 3, and so on. It will probably degrade somewhat at each stage, if a conversion happens.

Convert OGM to AVI, either uncompressed or Huffy. Edit, remux, whatever. KEEP AS AVI, do not convert, compress, or change format in ANY way. When you are all done, then and only then compress to target format.

[Questmark]

Nelson 37,
In regards to the Ogm to Avi link you gave-- is that any better than simply running the ogm through VDub Mod and using "Save As" avi with HuffyUV? Is the quality of one different from the other? Or is "Ogm to Avi" simply easier to use in some way?

Also, it would seem that if I didn't want to go through the process of learning and using Subtitle Workshop, that the only other way to go would be to use VDub Mod and the HuffyUV codec (which I've been reading up on). I've been thinking about trying to learn how to Frameserve from VDubMod to Vegas with the "Link To" program. I guess it's sort of like there's more than one way to skin a cat-- use Subtitle Workshop and Ogm to Avi, or use Avisynth and VDubMod and framserve to Vegas with hardsubs..... Each sounds a bit complicated in it's own ways. I guess the big question I have is whether one process produces better quality at the end than the other. Seems sort of equal to me.... ??? (If, indeed, Ogm to Avi actually converts the file with no loss of quality, like using the HuffyUV codec in VDub Mod)

BTW, thanks for all the help everyone-- I've been reading up on codecs, how things compress, loss of quality, etc. Avisynth and frameserving suddenly seem far more important/useful than I used to think.

[Nelson37]

That was not intended to be a link, I did not know there was such a program. "Save as" in Vdub is fine.

Subtitle Workshop is not hard at all, and this process will give you one dramatic benefit. SWITCHABLE subs. On if you like them, off if you don't. User control. I like to be in control. Also it just looks cool.

Quality wise, no difference in the video itself, unless you consider the amount of video permanently covered by the subs and lost forever as a quality loss.

Avisynth is a fantastic tool, well worth the time to learn it. Frameserving is absolutely essential.

You are well on your way. Keep reading, experimenting, and posting questions. In no time, you will be the envy of all your friends and the life of the party. Well, OK, maybe not.