AC3 and M2V Synchronization

[Crist]

Hi
I have captured MPEG2 file. Audio and Video in MPEG2 is very good. I render it as M2V and AC3 with Sony vegas 4.0. I am using Tempeng and DVD lab for authoring. After authoring when I play VOB in my computer, Audio and Video was out of synchronization. Usually I play VOB in my computer before I burn DVD. I use different timeline for Video - SMPTE non-drop(29.97 fps) and SMPTE drop(29.97 fps). But in both case audio and video was out ot synchronization. My MPEG2 file is 1:47:19 minutes long. After rendering as AC3, AC3 file shows 1:47:25 long. M2V file shows 1:47:19 minutes long.
As a first option I use AC3 delay for Audio/Video synchronization but After 15-20 minutes of movie it again out of synchronization.

My computer configuration is:
P4 - 2.6GHz Hyper Threading
512 MB RAM
120 GB SATA HD

My computer is fast enough. It take 20 minutes to render AC3 file and Approx 2 to 3 hours(depend of file size) to render M2V file.

Can somebody help me what is wrong? How can I synchronize Audio and Video?

Thanks

[ormonde]

"Can somebody help me what is wrong? How can I synchronize Audio and Video?"

Try this:

In TMPGENc, open with the "Project Wizard" page and load you m2v and ac3 files in the "Select Source File" page. (the dialog box after "Select Format") Then go to the next dialog, which is the "Filter Setting" page, and select "Source Range" and click "Next". In the Source Range, go to the bottom middle and you will see an "Audio Gap Correct" option. There you can adjust and compensate your audio with regards to synch issues.

[Crist]

AC3 and M2V synchronization

Thanks for Reply

I will use filter setting in TMPGEnc. I hope that it will work.

I have still one question why AC3 file is longer then M2V file. As I mention earlier that AC3 file is 1:47:25 long and M2V file is 1:47:19 minutes long. Original MPEG2 file is 1:47:19 minutes long.

If I render MPEG2 file as a MPA file, then size of MPA file is same as M2V.

[ormonde]

"Thanks for Reply"

Glad to be of help

"I have still one question why AC3 file is longer then M2V file."

Why not try and drop the mpeg file that you captured directly into "DVDLab". I'm not sure if DVDLab can create ac3 Dolby Digital sound, but if your original mpeg's sound was in synch, it seems like demuxing and muxing your file is taking a lot of extra steps. Check to see if DVDLab supports the creation of ac3 sound.

[sfheath]

"if your original mpeg's sound was in synch, it seems like demuxing and muxing your file is taking a lot of extra steps. "

just what I was thinking. Also, I think playing the "dvd folder" rather than the VOB might be better.

[Crist]

AC3 and M2V Synchronization

Thanks again for reply.

I use DVDLab for authoring DVD. I use Sony Vegas Vedio 4.0 to create AC3 Sound from MPEG2 File.

When I drop MPEG2 to DVDLab it create M2V and MPA file of same size. I don't use MPA in DVD because it is not valid DVD format. AC3 is valid DVD format and also take advantage of 5.1 surround sound Sony Vegas Vedio 4.0 . Usually audio use timecode 30.00 fps. I don't if it is a issue.

[ormonde]

"I don't use MPA in DVD because it is not valid DVD format. AC3 is valid DVD format"

When you say "MPA", do you really mean "MP2"? (MPEG-1 audio layer 2) MP2 is a totally acceptable audio format for DVD.

[Crist]

AC3 and M2V Synchronization

Yes, MPA means MP2(MPEG-1 audio layer 2).
Some of DVD playes does not support MP2 format. AC3 is only official supported audio format for DVD. I have burn some DVD with MP2 format and it works fine with Penasonic DVD player but I can not take advantange of 5.1 Dolby digital surround sound. I have render 5.1 Dolby digital AC3 file and I want to burn DVD with Dobly digital surround sound(AC3 Format.)

Do you know what is exactly Audio Bus and Audio Track?
How can I add second audio stream in DVD?


Thanks again

[ormonde]

"AC3 is only official supported audio format for DVD"

Your statement is not totally correct–especially in light of the fact that you said yourself "I have burn some DVD with MP2 format and it works fine with Panasonic DVD player". However, if you want "Digital Surround Sound" support, then I understand your position. Did you check and see if DVDLab can create AC3 Format? I think your audio synch problem could have something to do with using Sony vegas 4.0–possibly.

[Crist]

AC3 and M2V Synchronization

DVDLab does not create AC3. DVDLab support AC3 format to import it and author DVD. DVDLab have just one option to set delay for AC3.
I am trying to understand how Audio Bus and Audio track works in order to customize AC3 format. Do you know how it works?

Once again, do you know how to add second audio stream in DVD?

Thanks for your help.

[ormonde]

"Once again, do you know how to add second audio stream in DVD?"

Try to use a program called "IFOEdit". It's not the easiest program to understand at first, but should accomplish what you are seeking.