sound out of sync after using tmpgenc to encode xvid,divx

[jimblob]

Anyone help??
I have encoded a couple of xvid and div x movies with tmpgenc to mpg format, and when I try to play them back the picture is perfect,but the sound is out of sync by a second or two...Any help on fixing this problem would be a brain saver.


Cheers

[mats.hogberg]

Downloaded files? Then bad AVIs are pretty common, causing sync probs. Also encoding at a different frame rate than original causes a sync drift (a/v sync becomes gradually worse thruout the movie).
Cure for bad AVIs is to scan for bad frames with Virtual Dub, then save out a new AVI.

/Mats

[jimblob]

Thanks, the files seem to be fine when played on the pc,but when I change the format to mpg the sound is out of sync with the video.

Jim.

[yf2001usa]

Step one: use virtualdub to check if there are no bad frames in the xvid or divx. Cause if there are you can have problems converting them to mpg. if there are bad frames fix them. There are guides arround to do that.
Step two: always extract the audio with virtualdub out of the xivd or divx as PCM Audio, this will cause less problems.
Step three: encode the video of step 1 and the audio of step 2 with tmpgenc.

If you still got audio problems after that. I did with files where there was a few secs of black screen in the movie. Then u can use a wav editor to get the audio in sync, by eding some silence.

Yf

[jimblob]

Thanks a lot I will give this a go!

Cheers for your help

Jim.

[mats.hogberg]

Yes, even files with bad frames play fine on the PC, but do cause all kinds of problems when encoded. You'll find that almost every file dl'ed (specially using P2P apps like KaZaA) suffer in varying degree of bad frames and other problems, many to the point where the problems during conversion just doesn't make it worth while. Better to hook the telly to TV out from your graphics card.

/Mats

[jimblob]

What would I use to hook the pc to the tv??
Obviously it`some sort of lead from the graphic card?

Cheers

[mats.hogberg]

If you have TV out, there's a RCA female connector (Composite video out) that you plug into your TV composite video in. There's probably a SVideo mini-DIN that you can also use. Many TV's don't have an exclusive video in connector - in that case get a SCART connector with RCA connectors (like PlayStation). Many computer stores carry ready made cables for under $10.

/Mats

[IJM]

Hi,

I do a lot of AVI to DVD/MPEG2 conversions. I create PAL DVDs, but most of my sources tend to be frame rates other than 25fps. But I don't tend to find that its the encoding process (TMPGENC) that causes problems.

The majority (maybe 95%) of sound sync problems I get stem from problems in the source file. I have found that a lot of source files that at first seem fine, actually exhibit subtle audio sync problems. I've found that these get emphasised when converted to PAL MPEG.

So I've learned to check the source file over much more carefully first using Virtualdub. I do a quick check for bad frames, and then I check the audio sync carefully at various points in the file, just by eye and ear. I always start from keyframes in the beginning, the middle and end of the file. I tend to find that if it checks out okay, then it'll encode just fine.

I won't go into detail about how I fix problems I find (that's what DVDhelp.com's sound sync guides are for), but I will say that I tend to use Soundforge 6.0 and Virtualdub to measure the audio/video misalignment at various points in the file to diagnose the problem. Most of the time, I find that gradual sync is the problem, and so Soundforge's "Time Stretch" is the most common function I use.

To test, I use Virtualdub to glue together a test AVI, (usually copy video from source and audio from wav file). If this test AVI turns out okay, then usually the encoded MPEG will be fine.

I hope this helps.

Ian.

[LisaB]

nice idea on the virtual dub test, ian...I'd been using Avisynth.

Avisynth has an interesting function, DelayAudio. In AviSynth, you can use Trim to look at a specific point, and DelayAudio to play with the AV timing. you just open up your avs file in VDub or WMP. edit the avs. open again in VDub or WMP...and so on until you've found the right audio delay.

Is SoundForge the same as GoldWave?