Output file length differs...?!

[hunter_aran]

I tried searching for this and found no answer. I ripped separate episodes off a DVD and then used Avisynth and Megui to encode them in x264. On one of the discs, if I compare the output file to the original ripped file (in something like VLC) the output file is anywhere between 20-45 seconds longer than the original! I understand if it was shorter than it would probably indicate skipping from bad cells, but longer? The audio track demuxed from the original file, when remuxed with the encoded one is in sync too, which is great but doesn't make any sense if the new file is longer. FYI, the other DVDs don't have this problem--the encoded files match to the second. AND they were done in the same batch so nothing in the encoder changed. Maybe there's a simple explanation regarding timestamps (like some DVDs differ) that I just don't understand but it's been really bothering me. Any ideas?

[hello_hello]

Where are you getting the duration information for the DVD?
I've found sometimes if I open a DVD after ripping it, and maybe it's more likely after re-authoring it, the stated duration when I open it in MPC-HC and it's actual duration aren't the same. ie. the duration might state 1 hour 45 minutes & ten seconds but if you play the video right near the end you'll see it actually stops at 1 hour 42 minutes & thirty seconds etc. I'm fairly sure I've ripped a few DVDs and when opening them in MPC-HC the stated duration has been out by an hour or more. Especially if I play the video by opening the vob file rather than the IFO. They've still all converted okay though.

I've no idea why that happens or if that's what's happening in your case. Just a thought....

[hunter_aran]

I open the ripped vob chapter file (via mac the ripper) in vlc and look at the total length and then do the same for the encoded file. As far as what you've experienced, it is in some ways reassuring to know that you have had the time differ as well. I just thought I was going crazy or did something wrong when encoding, or that file was messed up somehow.

[Ghitulescu]

Does the audio stay in synch?

[hello_hello]

Does the audio stay in synch?

Yes, he said the audio stays in sync.

hunter_aran,
Another thought/guess.... maybe the audio and video are of slightly different lengths and the shortest one is given as the duration when you play the original file.
As an experiment (which maybe I should try if something similar happens again) you could open the vob file with a program such as VirtualDub, skip to the end and see what VirtualDub reports as the total number of frames, then compare that to the frame count of the encode.
Well at least you could if you used a PC but now I think about it you mentioned Mac and I know nothing about encoding/editing software for the Mac.

Or you could try something like MediaInfo to see what it says about the duration etc. Maybe have a look to see if the demuxed audio is a different length to the video. There's a link to a Mac GUI at the bottom of the page.
http://mediainfo.sourceforge.net/en

Of course I assume it's also possible something is just messed up... :)
If you come to any startling conclusions please let us know what you find.

[hunter_aran]

Yes the audio stays in sync.

I am using Avisynth/AvPSmod/VirtualDub to create the script and am running them in Megui to encode. I am running all these programs on Parallels via Windows XP SP3 so the programs look like they're running natively on my Macbook Pro.

That's a great idea to check in Mediainfo and the frame count in VDub. I should have realized this earlier!

Well it seems that Mediainfo still reports the same time difference as in VLC. However when I preview the files in Megui's preview window, the frame count is identical. So it doesn't make sense but it looks as though there is no problem! I watched a few files and they don't seem to have any issues either. I am using AnimeIVTC to detelecine so I thought that maybe decimating back to the correct FPS went wrong... I wonder if that maybe caused the timestamp to be weird?

Thanks for all the help!