Software for fixing MPEG-1 audio displacement

[idiotsavant]

I have an MPEG-1 VCD file where the audio is displaced from the video by ~250 ms. What software is out there that I can easily correct this? For AVI files it's real easy to do, as you can use VirtualDub to introduce a displacement (delay) of the audio and then ouput the video in a direct stream. Is there a similar software for MPEG-1. Thanks.

[megamachine]

You can do this with TMPGEnc, which is a free download for MPG-1 capabilities (though only a trial for MPG-2). However, it involves re-encoding the file, so is not as easy as the VDub method for AVIs. If you decide to try it, load your file, go to Settings, then Advanced, then open the Source Range, and at the bottom you can use "Audio Gap Correct." If you are sure of 250ms, it is easy, though otherwise might take some experimenting to get it right.

[idiotsavant]

Thank you, megamachine. Using VDub I can test approximately how large the displacement is and then try your method. I'll let you know. Thanks, again.

[simbalin]

Audio Corerction in MPEG

I'd recomment you use bbMPEG instead of TMPGEnc it need a littel reading to get into all the funktions, but bbMPEG simply provides the best Muxxer out there, though the encoding is pretty poor.


Like discribed above for TMPGEnc it is a "must" that u remultiplex (re-muxx) the Video.
bbMPEG has it as a basic feature to set delay times for Video Audio and Audio2 Stream (Audio2 only if u musse with two AudioStreams i.e. 2 languages). Standard fpr VCD is a delay time of 344 (ms) simply add the 250 to the Audio1 or Video delay time to fix it.

But trying around until your Streams fit proper together isn't a very "romatic" way to fix this Problem. Have a look at the MediaPlayer Classic (not a Microsoft product - freeware!). You can use it's internal routine for audioplayback which includes the possibility to enter a delay time in (ms). While the Video plays you can adjust this delay using + and - keys on your keyboard. Just adjust it until it fits right. Write down the delay time that is set now and use it instead of your 250ms guess.





Greetz Simbalin

[ormonde]

"For AVI files it's real easy to do, as you can use VirtualDub to introduce a displacement (delay) of the audio and then ouput the video in a direct stream. Is there a similar software for MPEG-1. Thanks."

Try to use VirtualDubMod–a variant of Virtual Dub. It has an mpeg filter, and use the "Audio Skew Correction" feature or similar method as Virtual Dub.

[idiotsavant]

Originally posted by megamachine
You can do this with TMPGEnc....load your file, go to Settings, then Advanced, then open the Source Range, and at the bottom you can use "Audio Gap Correct." If you are sure of 250ms, it is easy, though otherwise might take some experimenting to get it right.

I tried your suggestion. I'm using TMPGenc 12a, opened Source Range, and under Audio Skew I put in 250ms. It seems to have made the video and audio more out of synch. Should I have used -250ms instead? In VDub the delay would be positive if the audio starts before the video. Is it different in TMPGenc? It takes about two hours to re-encode, I guess I could try -250ms. Thanks for your help.

[megamachine]

I'm using 2.59, but it's probably a similar operation. Sounds like you compensated in the wrong direction. With TMPGEnc, you can encode just a couple of minutes and then stop and check out the result; no need to wait for the whole file to see how it came out.