Best way to trim clips from DVD with free software?

[SpeleoFool]

I've been wrestling with this for a few days and it looks like it's finally time to ask for help. All I want to do is cut a few clips from DVD source without resampling video (or at least only from I-frames) and keeping 5.1 audio. Is this possible, using only free software???

I have investigated various guides and hunted on the forums, but so far every method I've tried has been lacking. Here are some dead-ends I've hit:

I. Rip to VOB, then ???
Started by backing up DVD with DVD Decrypter in default file mode, then discovered most software apparently doesn't like VOBs.

II. Rip to M2V + AC3 with DVD Decrypter
Used IFO mode with DVD Decrypter to create .M2V + .AC3 files for the main movie. Under VTS_08 there is a PGC_01 the full length of the movie + a PGC_02 with zero-time. I backed up only the PGC_01 using full demux and got 4 audio files and 4 video files (video split into 1GB chunks--oops). Tried to feed these into Cuttermaran, but get a warning that days "this video contains temporal errors!" and the audio is out of sync. I abandoned this approach but later (step IV) came back to it.

III. Convert to MPEG2
I next tried converting the whole movie to MPEG2 with VOB2MPG, but had some trouble getting this format to load. The good news was that it seemed to play back without audio delays. The challenge was that most apps didn't like .MPG files. I tried Mpeg2Cut, and it seemed like an easy tool to use, but I didn't get any audio when I previewed the clip. I didn't find anything else that sounded as promising, so I changed my approach again.

IV. Try to Demux the VOBs or MPG for Cuttermaran
I decided to try to make Cuttermaran work since it seemed the most promising option I had. I had slightly better results using PGCDemux on the VOBs than with DVD Decrypter, mainly because I realized I could rip the whole movie as one big M2V (in hindsight, I'm sure I could have done this with DVD Decrypter by lifting the 1GB max file size). The results were only slightly better, though, because audio is somehow *way* off in Cuttermaran, as in whole minutes. And this seems to accelerate from the beginning of the movie, where sound is off by less than a second or so. Could it be a problem with playback rate or something? I want to be careful playing with those settings since my goal from the beginning has been to avoid resampling, and I worry that might happen if I mess with frame rates. In any case, I could find no easy way to correct the sound sync problem with this approach, so I abandoned it.

Additional Background
I have an old version of Vegas (3.0), and plan to upgrade to the latest Vegas + DVD. I downloaded the Vegas 7.0 demo and tried to cut my clip. I managed to create a "sub-clip" for the project easily with the Trimmer, but I couldn't save it. I copied nothing but that clip to the main project flow and rendered both MPG and AVI files, but both came up empty, leaving me with two questions: (1) are the blank files because it's demo software, or are my source files giving me problems? (2) Does the render process resample my clip? Is there any way to make sure the clip is not resampled (i.e., no quality loss)?

--

So, any ideas why trimming a clip is so difficult? Am I missing something obvious, or is this process just harder than it sounds? Also, any comments on whether Vegas can easily trim subclips without resampling?

Thanks!
Speleo.

[Edited post to correct typo on 'DVD Decrypter']

[manono]

Hi-

Depending on where in the DVD you're cutting, and how many cuts you have to make, your best bet may be to use VobBlanker for the job. Open the complete DVD on your hard drive in VobBlanker. Highlight your video in the top window so that it appears in the lower window. Highlight it in the lower window and hit "Cells". In the new window that opens, you'll see the various cells (chapters, usually) that make up the DVD. Highlight one that you want to cut a piece from and hit "Prev/Cut". Cut out what you want. It's pretty self-explanatory. In addition, there's more information in the included help file. The "gotcha" is that while you can cut in as many different cells as you like per session, you can make only 1 cut per cell during each session. If you want to make 2 or more cuts in the same cell, you'll have to "Process" it with one cut, and then reopen the processed DVD to make more cuts.

If this is OK with you, you'll keep everything except what you cut out. No demuxing or any of the other stuff you've tried without success is necessary. And depending on just how much you want to cut, and where, it may make you wish you had asked here much earlier.

[mats.hogberg]

DVDShrink in reauthor mode lets you specify start and end frames for what you want to rip. If you don't use any compression, it'll be an exact copy of the video on the DVD.
Depending on source DVD, it may have to be ripped with a more potent DVD ripper before being treated with Shrink.

/Mats

[SpeleoFool]

Depending on where in the DVD you're cutting, and how many cuts you have to make, your best bet may be to use VobBlanker for the job.

I am looking to collect a lot of small clips, like favorite scenes, quotable segments, etc. In most cases I expect my cuts to be 30 seconds or less in length. I have downloaded VobBlanker, but I was under the impression the granularity was whole VOBs, so I haven't attempted to use it yet.

DVDShrink in reauthor mode lets you specify start and end frames for what you want to rip.

Wow! That sounds like a real winner. I am already using DVDShrink for some backups, but didn't know about the reauthor feature. I will definitely give this a try!

Thanks, both of you, for your suggestions. I'll give these a try and will report back success or failure.

Cheers!
Speleo.

[SpeleoFool]

DVDShrink in reauthor mode lets you specify start and end frames for what you want to rip.

I'll give these a try and will report back success or failure.

Well, the DVDShrink reauthor method is a huge improvement, but it's not quite 100%. Perhaps someone can help with this last little wrinkle:

The good news is I was able to easily grab a test clip and export as VOB. The bad news is that because of I-frame granularity my clip is a little rough around the edges. This seemed like a perfect test case for Cuttermaran since it's supposed to be able to re-encode only before and after the first & last I-frames, leaving the main video intact. I used PgcDemux to convert the VOB to elemental streams, but I ran into the same problem as before with video / sound sync.

Cuttermaran reports the video file as 0:07,441 (223) in length with a frame rate of 29.97fps, but the audio is 0:09,312 (291). For the full movie files I tried earlier, the M2V clocks in at 01:17:56, while the audio is 01:37:24. In both cases, the video length is exactly 80% of the audio length. Anyone have any theories on why this might be happening & what I should do to correct it?

Thanks!
Speleo.

P.S. DVDShrink reports the clip time as 9 seconds, so I think the video is playing back too quickly.

[manono]

Boy, did I misunderstand. I thought you just wanted to remove some video from a DVD, getting back the DVD with some scenes cut out. Like some people want to make children-safe movies on DVD, cutting out the R rated scenes.

I use MPEG2Cut for what you're doing. I always get audio. Do you not have the AC3Filter installed? But it does only cut on I-Frames, and won't cut to a specific frame, or reencode a tiny bit if necessary.

Anyone have any theories on why this might be happening

Most likely a pulldown issue. Encoded at 23.976fps and has pulldown applied to output 29.97fps. 23.976/29.97=.8. I've never used Cuttermaran, so I don't know if it's a problem and, if so, how to fix it.