Virtual Dub question

[Trunks4191]

I noticed that when extravting the sound out of a AVi file, by pressing Audio < Direct stream Copy, i get a wav file which is really small in size. say 230 megs from a 700 meg file

But if i click Audio < Full processing mode
I get a wav file that is like 900 megs.
Is this right? and if so which mode is better to stick with? Does it make a big difference?

[Craig Tucker]

If you select direct stream copy, it saves the wav file as is. i.e. compressed with whatever codec was originally used. If you use full processing mode you can choose whatever codec you like for the audio file (providing it is installed on your PC) or to save it out as an uncompressed PCM wav file, hence the large size. You are taking a compressed audio stream and resaving it using no compression.

If you have a divx file where the audio has been compressed with a codec using a variable bitrate, you will have sync issues when you encode to mpeg because TMPGEnc cannot handle VBR audio.

You therefore need to save it uncompressed using full processing mode, this will create a large file which is approximately 10MB/min. You then use this wav file as the audio source in TMPGEnc.

Saving it using direct stream copy is a waste of time, as you are not changing the audio stream just saving a copy of it without the video. If you used this as your audio source in TMPGEnc, it would be no different to using the divx as the audio source, and you would still have sync problems.