How do I decompress audio into wav?

[Delgado]

Hi there,
This has probably been asked before but I couldn`t find the answer to it. When I want to use Virtual Dub on some files I get the message:

"VBR audio stream detected
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 compability. This may introduce up to 129873 ms of screw from the video stream. If this is unacceptable decompress the entire audio strea to an uncompressed WAV file and recompress with a constant bitrate encoder(bitrate: 129.0 + 9.8 kbps)"

After the movie is loaded it is totally off snych. Also seems there a loss in quality. So I would like to change the audio into wav and compress it again. Could someone give me a hint how to do it or may be a link where I can read about it?
Regards Del

[Craig Tucker]

https://www.videohelp.com/virtualdubaudio.htm

[Delgado]

Wow that`s fast. Thanks
I found something in the forum search but it didn`t really solve my problem. But now I know how to save the audio as a WAV file. Should I change the sampling rate? Also the audio doesn`t seem to be AC3. File information says compression: Frauenhofer IIS Mpeg Layer-3 Codec. What can I do to fix the problem explained above?

[Craig Tucker]

If you are making VCD or SVCD 44.1khz, for DVD 48khz. That link shows how to convert for 5 chanel ac3 or 2 channel audio stream

[Delgado]

Alright, now I have the audio as a WAV file. The message says I should recompress it with a bitrate encoder. Such as...tmpgenc? The wav file has about 87 MB. When I use tmpgenc it becomes about 900 MB. Sorry I think I`m hopeless.

[Craig Tucker]

When you save out the wav file in vdub uncompressed the filesize should be large, much more than 87mb assuming this is a movie. Uncompressed wav files are around 10mb/min so a 90 min movie would have an uncompressed wav file of around 900mb. If it is only 87mb then you are doing something wrong. Sounds like you have used direct stream copy and saved the wav file without uncompressing it. You need to use full processing mode and select no compression. Read the link I gave you carefully and try again.

[Delgado]

You were right. That was exactly what I was doing wrong. But now when I use Tmpgenc and try to merge the WAV audio with the old video again it becomes over 2 Gigs big even when I do it like it is described in your link. What should I do?

[Craig Tucker]

When you say merge I assume you mean encode, you are not multiplexing the wav file with the video stream are you ? What are you encoding to and what is the length of the movie.

[Delgado]

Right I meant encoding. The movie was about 705 MBs long. I just followed the instructions of the link you gave me. It says at the end I should encode again but like I said the file size becomes huge(2595 MB). How can I make it small again?

[Craig Tucker]

Right I meant encoding. The movie was about 705 MBs long. I just followed the instructions of the link you gave me. It says at the end I should encode again but like I said the file size becomes huge(2595 MB). How can I make it small again?

No, the movie is 705 mb in size, how long is it in time and what are you encoding it to, are you using a template in tmpgenc. The only 2 things that determines the filesize of the final file are the length of the file (time) and the bitrate used to encode.

[Hardcoreruss]

It sounds like what you are doing is just selecting the film when the wizard pops up.

1. Choose your movie for the video source.

2. Choose the file you just created in virtual dub for the audio source.

Then click encode. The file will probably be around the 800mb mark when completed.

[Delgado]

The length of the movie is 1:35h. In tmpgenc I`ve chosen Video-CD and NTSC when the "choose" format window pops up. Then the "select source file" window pops up and I choose non-interlace and 4:3 25 line(NTSC,704:480) like it was described in the link Craig gave me. I just click "next" then (found no "encode" anywhere) and the estimated file size is 948,56 MB now. I don`t know how I got 2,5 gigs yesterday Is there any possibility to make the file size even smaller by changing the bitrate or something?

[wee haggis]

The length of the movie is 1:35h. In tmpgenc I`ve chosen Video-CD and NTSC when the "choose" format window pops up. Then the "select source file" window pops up and I choose non-interlace and 4:3 25 line(NTSC,704:480) like it was described in the link Craig gave me. I just click "next" then (found no "encode" anywhere) and the estimated file size is 948,56 MB now. I don`t know how I got 2,5 gigs yesterday Is there any possibility to make the file size even smaller by changing the bitrate or something?

Yes...
https://www.videohelp.com/tmpgencxvcd.htm

[Hardcoreruss]

You can either follow the above guide or split the file over two discs. If you choose to do this post back and I will explain it.

[Delgado]

When I follow the guide and watch the preview I got no sound. Anyone has an idea why that could be? The Wav-file is OK I checked it before in WMP.

[Craig Tucker]

There is no sound in the preview in TMPGEnc.

[Delgado]

OK that`s something I can understand. Is there any way to see what size the movie will become?

[Craig Tucker]

If you are using the wizard it tells you what the filesize is going to be and what percentage of the disc it will take up, on one of the last windows.

[Delgado]

The Problem is the wizard tells me 958,56 MB but I want to change the bitrate to make it smaller. Is this this also possible with the wizard cuz the guide I followed only explains it without using the wizard.

[Craig Tucker]

You need to cancel the wizard and load the unlock template (the bitrate is locked for VCD). You can then reduce the bitrate to whatever you want. Use a bitrate calculator to see what bitrate to use for your length of movie, to get in on 1 CDR

[Delgado]

Oki just found the calculator in the link wee haggis gave me. I think now I can figure it out somehow. Thanks to all for your patience.