Problem decompressing audio using virtualdub

[ashsharma]

I'm having problems transcoding a divx file ot vcd.
The problem occurs when I try to decompress the audio using virtualdub to a .wav file, I get an error along the lines of "...could not decompress, no decompressor found"

I've tried reinstalling virtualdub, I've also analysed the file using AVIcodec and Gspot and both say that I have the correct codecs. The divx file seems to play ok on the pc although with low audio volume.

The audio is in AC3 format, has anyone got any ideas about what I can do?

Thanks in advance.

[ashsharma]

would goldwave be able to extract the audio?

[mats.hogberg]

Why not try? There's a free trial.
Even if VirtualDub can't decompress AC3, it ought to be able to save it out using direct stream copy.
Then convert to wav with Headac3he.
What are you aiming at?

/Mats

[ashsharma]

I'm trying to eventually get a vcd out of it, but if I can't extract the audio I might have to make it into a dvd instead.


Is there no decompressor I can download to work with virtualdub?
Or how about virtualdub mod?

If i did a direct stream copy then used Headac3he, would I be able to change it to 44100Hz?

[ashsharma]

I'm trying to eventually get a vcd out of it, but if I can't extract the audio I might have to make it into a dvd instead.


Is there no decompressor I can download to work with virtualdub?
Or how about virtualdub mod?

If i did a direct stream copy then used Headac3he, would I be able to change it to 44100Hz?

[mats.hogberg]

If i did a direct stream copy then used Headac3he, would I be able to change it to 44100Hz?

Yes, then you have it in wav format, and can do just about anything. To do a sample rate conversion, you could try GoldWave or SSRC (that SVCD2DVD uses).

/Mats

[ashsharma]

ok, but is there no decompressing tool I can download to work with virtualdub?

[feenix]

You could try this. Download and install Ac3 acm decompressor (Freeware- see tools). Open your avi in virtualdub and ,under 'audio' ,select 'full processing', select 'compression' and choose 'no compression pcm'. Then select 'conversion' and choose '44100'.

Then under the file menu choose 'save wav' (takes only a couple of minutes for a 2 hour movie) this will give you a 2 channel 44100 wav file which you can then use as source for your vcd

[mats.hogberg]

With the right codecs installed, VirtualDub has no prob with AC3 IIRC.
The Moonlight Odio Dekoda is what I have on my system. Seems to have vanished from the site tho... No, wait! Here it is!

/Mats

[ashsharma]

ok I'll try that, so i just need to download and install Ac3 acm decompressor and then run virtualdub as usual?

edit: I mean, virtualdub will locate the new deompressor automatically?

[feenix]

Mats,

Never heard of that filter before! What's the difference between that and the Ac3 acm decompressor? Might be useful if it's more comprehensive.

[feenix]

ashsharma,

yep it should do. Did for me anyway.

[SMoKe MaN]

In order to decompress AC3 Audio with VirtualDub, you will need to install the AC3 ACM Decompressor and then u will be able to convert it to WAV directly using VirtualDub. just extract the files to any folder u like, right click on the file AC3ACM.inf and then choose Install.

another option is to just extract the AC3 by using Direct Stream Copy, rename it to xxx.ac3 and finaly convert it to wav by using Headac3he or BeSweet.

[mats.hogberg]

What's the difference between that and the Ac3 acm decompressor?

No idea. When I read the readme, it seems just like an AllInOne mpg1/2/2.5 layer 1/2/3 and LPCM decoder - not a word about AC3...

/Mats

[ashsharma]

ok thanks guys.

will i get the same results using virtualdub (with AC3 ACM Decompressor) as I would using a direct stream copy then converting with besweet?

[feenix]

ashsharma,

Yeah you should do. Although why stick another program in the process? Also if you've not used Besweet before it can be a bit daunting.

[ashsharma]

You're right feenix, no point using besweet then.

OK, I've just thought of another question which is quite simple but not related really.

I converted another divx film to dvd a couple of weeks ago, I then burned it to a dvd+rw using Nero and Tmpgenc dvd author. I since then deleted the transcoded version from my hard drive. Now I want the film on a permanent Dvd+r, so can I simply do a direct disk copy from the +rw dvd using Nero and will it keep all the chapters. Or do I have to re-transcode it using tmpgenc (which took about 8 hours!)?

[feenix]

Don't do 'DVD's' I'm afraid (I know a rare and bizarre thing on this site now!), but as long as you have the software to copy DVD (and presumably with Nero you do?) I don't see why you would have to re-encode or re-author. It has got any protection on it.

[ashsharma]

OK, I downloaded AC3 ACM Decompressor and it worked perfectly... for the first divx file, but when I try to open the 2nd file into virtualdub i get the following error


An integer division by zero occurred in module 'xvid'...
...while decompressing video frame 0 with "XviD MPEG-4 Codec" [biCompression=44495658] (VideoSource.cpp:1772).

any ideas what i can do to fix the divx file?

[feenix]

Umm.........never seen that before!

The only thing I can think of is that it's an Xvid file not a divx as you said your first file was. Maybe you need a more upto date xvid codec?

Other than that not much idea I'm afraid.

[ashsharma]

It's alright, I've sorted it. The divx file had a few bad frames at the start, managed to download a fix.
Thanks all the same!