Latest How To about audio sync seems crazy

[dumwaldo]

just noticed the latest how to's on the home page and this one http://www.vcdhelp.com/sync.htm seems like an awfull lot of effort for something that TMPGEnc can do alone in a few mouse clicks.

load your clip into TMPGEnc and click the 'Setting' button

in the 'MPEG setting' dialog that opens select the 'Advanced' tab

check off the box next to 'Source range' and then double click the words 'Source range'

in the 'Source range' dialog that opens there is a feild to enter an 'Audio gap correct' value in millisecconds

use a positive value to move the audio forward and a negative to move it backwards (ok that might be backwards i havent fixed audio in a while)

i highly reccomend making a 1 or 2 minute long clip of your video to play with adjusting the audio gap setting till you are pleased with the sync then load up the whole thing and let it run

it should also be noted that this will only shift the position of the audio. if the audio is stretched or shrunken this will not fix it. that is considerably more difficult to fix and requires far more time and patience that any video on earth is worth.

well there you go slap a few screen shots and you have a much easier how to guide to achieve the same result.

BTW you can do the same thing to an avi with virtual dub by simply pressing Ctrl+i and setting a value in the 'Audio skew correction' section.

[bbb]

Me too.

I was reading the doom9 guide which is linked to the page (2 links away actually). The doom9 guide required insertion of silense audio frames and deletion of silense audio frames and the use of a MPEG2 editor to syncronize each audible event to the corresponding video event in the movie. It's unbelievably, hair-yankingly, insane for movies with lots of dialog.

However, I read 2 years ago that stretching or compacting audio is not that difficult. You just need a specific audio editor (I forgot if it was CoolEdit or SoundForge) and find out the exact number of frames in the video (and convert the frames into minuteseconds:hundredths-of-seconds and stretch/compact the audio to match the video play time). However, I don't know if such a stretching or compacting will match up all the lips to the talk; only that the sounds will begin and end with the video.

It's probably best not to mess with desynced audio. Just forget the desynced clip or wait until a better ripper-encoder comes out.

[Baldrick]

http://www.vcdhelp.com/faq.htm#synch

[agzz]

just adding that cooledit can stretch sound.

[dumwaldo]

WOW thank you Baldrick i take that as a great compliment. had i known it was going to be immortalized perhaps i would have use proper rules of grammer and spelling.

bbb and agzz
you are both correct and yes cool edit can be used to stretch or compress the audio to fit with the video however IMHO there is nothing out there that is worth the amount of effort it takes to perform this procedure. if you have a one of a kind home movie with great sentimental value i could understand spending the effort but most of the video on the internet is trash. for instance i just capped good morning america to share with some people i know outside america. i lost audio sync in one segment of about 3 minutes. did i fix the audio? hell no, and it is sending to a friend right now. why? because it is not a big deal... my friend will still enjoy seeing this and he will still get all the same info that i did from it. and in a weaks time neither one of us will have it anymore because we have watched it.

peace out,
dumwaldo

[Dhruv]

I got alot of e-mails about sync probs using my DVD Ripping Guide and I suggested the TMPGEnc way, but most said that didn't work (don't ask me why?!?) so thats why I made this guide.

[chiga]

I know this is quite a while after the original tip was posted, but I just had to leave this feedback to let you vcdhelp administrators know how much the info & resources on this forum is valued & how everyday, some newbie is learning from info that may be 'common sense' or old news to some others.

Thanks for this excellent guide, dumwaldo, and thanks to Baldrick for posting it to the FAQ (where I found it). The other guides/links were way above my skills & means, so I gave this method a shot & it worked like a charm!

THANK YOU!

[sohc427]

I tried the methods from doom9, when I attempt to author the DVD using DVDIT! PE, both the audio and video get demultiplexed and will not stay in sync. I can sync the audio and video perfectly using the offset option on an .avi file in Virtualdub created from these two separate files by offsetting the audio by 500 ms - I tried saving the .wav file from the saved in-sync avi file and using this .wav file for the mpeg2 video file I am using (this was done using Tmpgenc 2.53 using VBR DVD specs from Rui Del *****'s guide). Sonic's website basically says I'm screwed, that files encoded using VBR will be out-of-sync - this is due to DVDIT! PE having to demultiplex then remultiplex the files and they have no further solution other than to reencode using CBR.

I tried saving the .ac3 files as a .wav file using Goldweave (from the instructions on this site for VCD) and editing the file, I just seem to be wasting alot of time without getting anywhere since DVDIT! PE just demultiplexes/remultiplexes at its own will.

I have done about 4 other rip/reencodes using SmartRipper, saving separate single VOB files containing just the movie and separate single .ac3 files then encoding to a lower bitrate with TMpgenc and used DVDIT! PE to author the DVD with great success, this is the first time this has happened. I have a copy of BBmpeg, I just don't see a way to offset the audio when multiplexing, DVDIT! PE will probably just demultiplex/remultiplex out of sync anyway.

One thing I did notice, on previous authoring attempts DVDIT! PE did not do the demultiplex step, it accepted the video without demultiplexing the video - when I examine the video file in TMPGenc, there is a "padding stream" also - I tried demultiplexing with TMPGenc, yet even after demultiplexing DVDIT! PE still wants to demultiplex before encoding. Is this "padding stream" causing the out-of-sync issue with the audio?

I have Ahead Nero 5.5.9, is there a way I can just burn the multiplexed audio/video mpeg2 files in Nero, or will Nero also demultiplex/remultiplex the files? I tried once awhile back, I kept getting the message this file is above 2gig I have to use UDF not ISO, yet when I set UDF it doesn't hold the setting, it keeps reverting to ISO! Is there an MPEG2 video/audio synch/authoring program available that will allow me to sync the audio with the video and then burn the files without being demultiplexed out of sync? Any help will be greatly appreciated.