Comments on: Why do the sound and video sometimes get out of synch when ripping DVDs?

Question: Why do the sound and video sometimes get out of synch when ripping DVDs?

psmealey — Fri, 31 Aug 2007 04:31:33 -0800

When ripping some DVDs to my hard drive, why do the sound and video get out of synch?

I generally use Mac the Ripper for doing this, and yes, I only do this for DVD's that I own. My question is that for some DVDs (particularly "Almost Famous", and "Woodstock: the Movie"), the audio gets out of synch with the video by several seconds. For other DVDs ("Rock Star", "24 Hour Party People"), it works just fine. Why does this happen, and is there anything that can be done to adjust for it?

By: flabdablet

flabdablet — Fri, 31 Aug 2007 05:42:08 -0800

I use mencoder (via AcidRip) for the same job, and sometimes I end up with rips that have a consistent half-second or so between audio and video for the whole movie; audio and video don't drift apart, though. Fortunately mplayer has keyboard controls for adjusting A-V delay (+ and - keys) so I've never bothered re-ripping. Perhaps you might try out OS X versions of mencoder and mplayer on your problematic discs.

By: PowerCat

PowerCat — Fri, 31 Aug 2007 05:43:02 -0800

From my experience, two things can desync a movie encoding.
The framerate of the images is slower than the framerate at which the sound is set.
Maybe the video is at 30 fps but the audio is set for 29.97 fps, and so on. Make sure to check that.

Also it's possible that high cpu usage while encoding could result in unexpected artifacts.

By: pompomtom

pompomtom — Fri, 31 Aug 2007 06:15:08 -0800

Where I've had rips which played poorly, I found that VLC plays them OK.

Also, try Handbrake.

By: smackfu

smackfu — Fri, 31 Aug 2007 06:26:39 -0800

Just ripping, or re-encoding?

Because ripping is really just copying the files. If it's not playing right, I would look first to the player software, not the ripper.

By: bryanjbusch

bryanjbusch — Fri, 31 Aug 2007 06:57:46 -0800

PowerCat has said the most useful thing so far, but consider this another vote for HandBrake

By: psmealey

psmealey — Fri, 31 Aug 2007 06:59:07 -0800

You're right, of course, smackfu. I inaccurately phrased my question/issue. It's not in ripping the DVDs. Mac the Ripper works just fine for this purpose. The problem is in re-encoding them. The application I use for this is Cinematize. It works perfectly most of the time, but a little more than 10% of the time, the audio and video are de-synched as described above.

By: Steven C. Den Beste

Steven C. Den Beste — Fri, 31 Aug 2007 10:22:13 -0800

With NTSC, the correct frame rate is 29.97 frames per second. If you encode with 30 frames per second, sound and visuals will desync.

By: jbrjake

jbrjake — Sat, 01 Sep 2007 07:00:04 -0800

It's possible you're losing sync because of gaps in the timestamps of the audio samples...If so, MPEG Streamclip can fix those audio timecode breaks.

I wouldn't hold out much luck that HandBrake would reencode without losing sync, but it might be worth a shot if nothing else works.