Sync problem saving audio from Virtual Dub

[CalCop]

Everytime I open a DVIX file in order to save the audio to a wav file I get an error code.
"VirtualDub has detected an improper VBR audio encoding in the source AVI file and will rewrite the audio header with standard CBR values during processing for better compatibility. This may introduce up to 19074 ms of shew from the video stream. If this is unacceptable, decompress the entire audio stream to an uncompressed Wav file and recompress with a constant bitrate encoder. (bitrate:143.6)
When I attempt to encode the audio and video using TMPGEnc...the file remains out of sync. I've searched and tried most everything listed in the help files..nothing seems to work...

[mats.hogberg]

In VDub, use "Direct Stream Copy" under Audio, then "Save WAV" under file.
This will give you a file ???.wav, which is not a wav file, but whatever audio compression method used in the DivX (mostly mp3 or ac3...)
Now, rename this ???.wav to the correct extension and decode this (mp3/ac3) to wav with a suitable mp3/ac3towav app.
Use this wav as audio source in your mpeg encoder.

/Mats

[mb571]

You need to extract the audio with the option
"Full Processing" then "save wav" not Direct Stream as mentioned above.

https://www.videohelp.com/divxtovcd.htm#audio

Mark

[mats.hogberg]

Sorry to contradict, but -Yes, use direct stream copy. If VirtualDub complains about "improper VBR audio", that's because it can't handle it. Full processing mode will force VDub to do just that, which will fail. Direct stream on the other hand, lets VDub spit out the audio track without touching it, leaving the audio part just as it was when interleaved with the video. Then take care of it with a dedicated audio decoder/converter.

/Mats

[Mr Grumpy]

I'm confused

I always use "Full Processing", downsampling to 44100, 16-bit HQ and I don't recall having a problem

<edit> Just remembered, this is OK when using 2-channel audio. I do use "direct stream" when the audio is AC3.

[mats.hogberg]

Might be, but to me this sounds like:

I have a book, written in a language I can't read very well, so I tell you so (I've found "improper VBR audio"!).
You then ask me to translate it into some other language (Save audio, Full processing). I heavily suspect that my translation will also suffer from my poor understanding of the original language?
If you on the other hand tell me to just give you the book and let you (equipped with a better understanding of this "VBR audio language") do the translation, it's no problem to me, I just hand it over, without even opening it. (Direct stream copy)

Maybe the analogy isn't true, but you wont lose anything by carrying out the ???towav decoding with an external app. (But then again, I'm obsessed with always using the appropriate tool for the specific task

/Mats

[antoniosgubba]

My view: :P

For VBR use full processing mode.

For AC3 ONLY use direct stream copy.

I've always used full processing mode whether the VBR warning comes up or not...and I've never had problems (for AC3 use direct stream copy then convert to WAV with either Besweet or Goldwave)

[ZippyP.]

Don't bother with VDub at all when you get a VBR warning. Use Goldwave, load in the Avi, select save....Voila! 8)

[Mr Grumpy]

I didn't know Goldwave supported AVI


I'll give that a try.

Can you Time Warp the audio straight from an AVI too? (I'll try it tonight when I get home anyway, it's just because I'm impatient )

[American]

On the following sunject..."VirtualDub has detected an improper VBR audio encoding in the source AVI file and will rewrite the audio header with standard CBR values during processing for better compatibility. This may introduce up to 12122 ms of shew from the video stream. If this is unacceptable, decompress the entire audio stream to an uncompressed Wav file and recompress with a constant bitrate encoder. (bitrate:133.5-19.5kbps)

Ive tryed both settings and they still dont work,

also noticed on the frisbie, that the first 20min., the audio is correct then it goes bad. ive tryed everything, think im going to have to watch it on my com.

or can anyone sugest another option?

[Mr Grumpy]

also noticed on the frisbie, that the first 20min., the audio is correct then it goes bad.

If the audio starts off OK, then at some point in the film, loses sync (rather than gradually drifting all the way through the film) sounds like there might be some bad frames in the AVI. Use VDub to scan for bad frames (Under 'video' menu). If any are found, just save away the AVI to a new file (using direct stream copy for both audio and video) and try again using the new AVI.

[American]

O.K. will try, but still have the error message when i open VD

[mats.hogberg]

American, that's no error message, just VDub telling you that the AVI has an audio stream that it can't handle correctly, and is best taken care of outside VDub. You still have to scan it for bad frames!

/Mats

[American]

No bad frames

[mats.hogberg]

In VDub, use "Direct Stream Copy" under Audio, then "Save WAV" under file.
This will give you a file ???.wav, which is not a wav file, but whatever audio compression method used in the DivX (mostly mp3 or ac3...)
Now, rename this ???.wav to the correct extension and decode this (mp3/ac3) to wav with a suitable mp3/ac3towav app.
Use this wav as audio source in your mpeg encoder.

You've done above, scanned the AVI for bad frames in VDub (no bad frames detected), and the audio/video still goes out of sync suddenly after 20 minutes? In that case I'm out of ideas!

/Mats

[Laddydaddy]

In order to find bad frames you should be using V-dub MP3 freeze. It works better that other versions of Virtual Dub in locating bad frames. It will make a log of any bad frames you have. Be advised however even this version of V-Dub is not fool proof. It did not detect some bad frames in an avi file I had. I encoded a film using Main Concept and got error messages at the 60 minute mark. I used V-dub MP3 freeze to scan for bad frames and it said there were none. I then encoded the file with TMPG without any difficulty. When I watched the video on my DVD player sure enough I saw the bad frames at the 60 minute mark. As I explained in a previous post I saw a swirl of colors and some of the characters in the film started splitting up. After the bad frames played out, the rest of the video was out of sync. I went back to virtual dub and manually inspected the frames at the 60 minute mark. Just as in my DVD, after the bad frames played out, the entire rest of the film was out of sync. To solve the problem I had to split the film in two. I encoded the film before the bad frames as I normally would. I then encoded the rest of the film after the bad frames using the interleaving tool in the audio section of virtual dub. It will offset the audio to match the film to keep it in sync. It's a trial and error procedure to plug in the right number of ms you want your audio to be skewed. When you open up the audio control you will see what I am talking about. If your bad frames have thrown the film out of sync getting rid of them may not help put the video in sync with the audio. Sorry to be so long winded.

[Selena21]

I used virtualdub to scan for bad frames but none were found.As I had ac3 audio I saved the audio as a .wav file and then I renamed it to .ac3.I opened HeadAC3he loaded the ac3 audio and started the conversion but mid through i recieved this error "Bad syncord at frame 77284.The ac3 stream is probably corrupt. What am I doing wrong to recieve this message as all the movies with ac3 audio when trying to convert them with HeadAC3he i recieve an error?

[Mr Grumpy]

What am I doing wrong to recieve this message as all the movies with ac3 audio when trying to convert them with HeadAC3he i recieve an error?

Not too sure what (if anything) you are doing wrong, but you can use AC3Fix to correct the AC3 stream before converting. You can find AC3Fix here

[antoniosgubba]

Best way to convert AC3 sound?

Forget Headache/Besweet/AC3fix etc.....just load the movie into Goldwave and save out the WAV....ten times quicker with no errors.

[ZippyP.]

Best way to convert AC3 sound?.....just load the movie into Goldwave and save out the WAV.

I'll second that! 8)

[antoniosgubba]

Actually Zippy firsted that!...I got the idea from him!

[Selena21]

Can you please tell me how to use Goldwave to convert from ac3 to wave as the programm won't accept the ac3 file.

[ZippyP.]

You need the AC3 codec installed on your system, it's in the Tools section on the left.

[Selena21]

I already have that. Now I downloaded AC3fix but when I unzipped it the programm won't open.

[American]

Matt, and all the other helpers, I gave up on that film, Matt, I did X-actly what u xplained but still didnt work, , but I will xplain 1 more time what the problem was....
Full .avi, (no problem to watch on com)
Vdub it (wave)
Tmeg it
burn it
Started to watch, after abt. 20 min. out of sycrn.

Well for the best I tryed
P.S. But I dont give up EASY

[mats.hogberg]

Only problem I see is "VDub it (wave)" Should be:

• VDub it (AC3)
  Convert AC3 to to WAV with HeadAC3he

Or extract audio directly to WAV with Goldwave as suggested in some posts. (Never tried it myself tho...)

/Mats
PS! But then again, sometimes it's just not worth the trouble. DS

[American]

Now u got me, Whats AC3 ?

[mats.hogberg]

Sorry - I made the presumption that the audio stream was encoded as AC3, as AC3 is mentioned alot in this thread, but not by you, I now see. It may be MP3 as well (or OGG if you're really unlucky! )
Whatever, when you save WAV using direct stream copy, you get the sound in the encoding it once was (even if VDub will persist in naming it ???.wav), and have to turn it into a wav yourself, hopefully doing a better job at it than VDub does.

/Mats

[American]

O.K., The file info from V-Dub 1.4.11, brings as a mp3, but brings up the improper warning when i open the file, The V-Dub mp3, also calls it a mp3 file, with no error,also tryed with Goldwave, and encoded it like u said, but "ALL" previews showed slide at abt. 20 min. in to film.

But from playing with this film, i'm not sure if i tryed direct stream copy?, but then again, i might have?

Will try "1" More time

[antoniosgubba]

Selena...AC3fix is a DOS application...you can't just double click it to run it...I know how to do it but its too complicated to explain here.....use Goldwave!!...so much easier!...you said Goldwave wouldn't accept the AC3 file, well you don't need to load the AC3 file into Goldwave...what you do is load the entire movie into Goldwave, then just click "file" then "save as"..and it will save the audio as a normal WAV.