Audio sync problems

vbimport

#1

can anybody tell me what to do when the audio goes out of sync with the video. i have used tmpegenc, also dvd2svcd the source are divx files
all seems well the at different parts of the movies the sound goes out of sync
is this file damaged or am i doing something wrong. can it be fixed
does not happen on all movies

any advise please


#2

Yes, sounds like the avi was damaged. But try ripping out the audio with Nandub and mux that in with the video file (after converting manually to AC3).

Else, read the Tutorial about how to fix the problem.


#3

sorry chickenman you’ve lost me, could you explain a bit more in depth

thanks


#4

As I said, load the avi into Nandub, set Audio to Full Processing Mode, then in File, hit Save WAV. Use ffMPEGGui to convert the WAV to AC3. I assume your making a DVDR from the avi, so just use the origianl encoded *.mpv video file and the new *.ac3 file in TMPGEnc DVD Author to make the VIDEO_TS folder and vob files ready to burn.


#5

do you rip the sound with nandub when its in divx format or when its encoded to mpeg

p.s is nandub the same as virtual dub


#6

Yes, while in AVI format. Nandub is similar to VirtualDUB (based on the same code) but handles AC3, VBR MP3 and other audio formats that VD does not.


#7

Sound Sync

Sometimes ripping the sound to a wav file and recombining will fix it, so try that first.

Find the bad frame:

Audio sync will go out when there is a video frame data error and the following frames are out of sync. To find this spot:
open v-dub/video & audio to direct stream copy/file/open video file
then, at the bottom of the open video file menu click on the bullet (ask for extended options after this dialog)/left click twice on the file that you want to check
left click on bullet (re-drive keyname flags)/ok

The procedure will now run until it finds the first damaged video frame, note the frame number. Close v-dub, re-open and video & audio at DSC and open file as normal, use slider or frame forward, etc to go to the bad video frame (number recorded). Some of the immediately following frames will probably be bad as well; the frame forward button will check them for you. Sometimes the whole keyframe will be bad. Split/edit the bad frames.

Run redrive keyname flags on the remainder, etc.

Resync audio:

Open the file in virtual dub and under audio click interleaving. In audio skew correction 1000ms = 1 sec. Use negative numbers when the sound comes after the movement; use positive numbers when the sound comes before the movement. Move in increments of 1000 at first. Direct stream copy the video and audio and save as avi.

A little trial and error then you can get it perfect. Once you get it to within +-100 of being right it’ll be close enough and won’t be noticeable.

If the sound is out a different amount at different points (the norm) in the movie then you can try this and it sometimes works.

Split the file into 2, 3 or maybe even 4 parts depending on how bad the sound is out of sync, and correct the different parts different amounts as necessary to get it right. You can rejoin them by opening the first file in virtual dub then clicking “append avi segment” under file. Choose the next piece and so on, and direct stream copy and save as avi.


#8

Note:

If you run a program called divx repair, http://divfix.maxeline.com/divfix.html - it will automaticall remove the bad frames and repair the movie file.


#9

doo524, the link you gave is to DivFix and NOT DivX Repair. DivxRepair can be found at http://divxrepair.sourceforge.net/


#10

Correction the prog site location is http:/divxrepair.sourceforge.net/

re chickenman.


#11

#12

Doo524, Media info will give the exact information of the delay in terms of miliseconds. Pretty handy.