Out of Sync

May 7, 2008 1:00 PM

After burning a movie file to a DVD I've noticed that the audio is horrendously out of sync. How can this be fixed?

I burnt an AVI file to a DVD using DVD flick and upon my watching it, I've noticed that the audio is so out of sync that the film becomes unwatchable. The audio was a little out of sync when I watched the actual AVI file on my computer but nowhere near the level it is after burning.

So how can I burn a DVD with normal sound?

posted by Funky Claude to computers & internet (6 comments total)

I can't give you a direct answer, as DVD audio sync can get kind of crazy...but doom9.org has just about every solution there is for burning and ripping DVDs.
posted by toekneebullard at 1:37 PM on May 7

I had the same problem with the Roxio DVD creation software. The only way I could get it to work was to extract the audio, cut out a second (or whatever) from the beginning, and reburn the DVD using the new audio track.

This was complicated by the fact that the lag only manifested on the final product, not the preview. I hope you find an easier way!
posted by Hermes32 at 1:52 PM on May 7

Not an answer, but just FWIW: In several years of making DVDs from all sorts of sources (DTV, DV, AVI/MKV/RM/MOV/MP4 files, downloads of dubious provenance, etc) I have never had one be / go out of sync without obvious reason (out of sync in the original, major audio or video dropouts / corruption, DTV timecode discontinuities, etc). I put this down to 2 things:

1. I use the proper tools, even freeware / GPL ones, not all-in-one converters. I demux the files to separate audio & video (I know, this sounds on the face of it like asking for trouble!) using the appropriate demuxer, then convert them to MPEG-2 video using TMPGEnc, FreeEnc, HCenc, Qenc, etc. Audio gets converted to MP2 or AC3 as appropriate, generally using one of the ffmpeg or besweet based tools. The 2 source files - audio and video - then get loaded into a proper DVD creator (e.g. DVDLabPro, which is the one piece of commercial software I couldn't do without), the DVD menus / structure / layout created, then compiled and burnt.
2. I'm in PAL-land, so I generally don't have to deal with the whole 23.976 / 29.97 FPS thing, and the inevitable mis-converting and mis-flagging of telecine & framerates in the source and destination that goes along with that. (In short, a hell of a lot of people don't know what they're doing, even some of the alleged "experts" in the dodgy downloads scene...)

Quick thought: if it's out by a fixed amount through the whole movie (i.e. not progressively getting worse, which would tend to indicate either an audio bitrate problem (e.g. 44.1k source flagged as 48k) or a video framerate flagging problem), try cutting a couple of frames off the beginning of the source file (using Virtualdub or whatever's appropriate) before encoding.
posted by Pinback at 5:44 PM on May 7

Pinback raises a good point: is the synchronization error constant, or does it get worse the further into the video you get?

One of the most common reasons for progressive desynchronization is encoding with an incorrect frame rate. The correct rate for NTSC is not 30 fps, it's 29.97. The reason for the kludge is historical, but it's not a negligible difference. In one hour it yields an error of 3.6 seconds.
posted by Class Goat at 6:00 PM on May 7

If you play it back in VLC you can change the audio sync to compensate in the Advanced settings. Doesn't solve your general problem, I know.
posted by AmbroseChapel at 6:38 PM on May 7

The error does seem to remain constant for the whole video. Thanks for the suggestions so far.
posted by Funky Claude at 1:04 PM on May 8