why is the audio missing from the .avi file?

March 9, 2008 8:25 PM

Help me get audio from a camcorder?

I'm importing a video from a Panasonic 3ccd camcorder to a Windows XP PC. I'm using VirtualDub to capture AVI. When I play the DV tape on the camcorder, I can hear the recorded audio, but when I import the video, and play it, there's no audio. The AVI file seems to contain audio information though. I checked all the settings, (for example system sounds are fine). The transfer is through USB (the firewire cable doesn't seem to work). I'm new to this stuff, so I would be grateful for any advice and/or links to suitable websites.

posted by dhruva to technology (11 comments total)

What are your audio settings in VDub? You tried "Source audio" with "Direct stream copy"?
posted by whatisish at 9:03 PM on March 9, 2008

Yes it's at Source Audio and Direct Stream copy.
posted by dhruva at 9:08 PM on March 9, 2008

If it's not VDub settings, you might consider a post at VideoHelp.com. A good active site with lots of people who know their stuff.
posted by whatisish at 9:10 PM on March 9, 2008

Does the sound actually play through your computer sound card when you're capturing? I think (according to the VDub docs) it needs to be set up as such to get the sound.
posted by whatisish at 9:16 PM on March 9, 2008

or maybe not... per the above link...

I can capture DV through VirtualDub, but I get the audio out of my sound card instead.

Video for Windows only captures audio through a sound device; with DV, the audio is interleaved with the video itself. I don't have any DV specs, so I can't make VirtualDub extract the audio.
posted by whatisish at 9:19 PM on March 9, 2008

It doesnt come on the sound card. Do you reckon I need to have a separate cable for sound?
posted by dhruva at 9:30 PM on March 9, 2008

And also, the AVI file that I get seems to have audio information on it. So audio is probably getting recorded, no?
posted by dhruva at 9:34 PM on March 9, 2008

Another check... When you open the volume control panel (start, run, sndvol32.exe) and click on Options, Properties, and click on the Recording radio button, are all of the volume controls checked? If not, check them and click on OK. Then recheck the volumes.

The AVI file seems to contain audio information though.

I'm confused by that statement. How does it seem to contain audio information?
posted by whatisish at 9:36 PM on March 9, 2008

Re audio information: the file details sampling rate, # channels, Compression, length etc etc.

Ok i checked all the volume control options. All the volumes are at max. No difference.
posted by dhruva at 9:43 PM on March 9, 2008

The clue is there: The Video For Windows (VfW) framework doesn't handle audio interleaved in a DV Type 1 stream, which is the format used for USB/Firewire transfers. VDub only handles VfW, therefore won't see the source audio. The 'audio information' you see in the VDub capture is an empty audio stream recorded from whatever VfW audio device is the default, probably line or mic in.

Basically, you'll need to import your video to the PC using something that uses the ActiveMovie / DirectX framework, which IIRC does handle DV Type 1. Effectively, these days this means "anything other than VDub". Once captured, you can save this as a DV Type 2 file (an additional separate audio track as well as audio data interleaved with the video data) and VDub should see & play the original audio.
posted by Pinback at 5:32 PM on March 10, 2008

> you'll need to import your video to the PC using something that uses the ActiveMovie / DirectX framework,

Can you recommend a program to use?
posted by dhruva at 6:14 PM on March 10, 2008