Why don't I have any audio?

[pchap]

Hi,

I'm hoping someone can help a newbie get to the bottom of a missing audio mystery!

I'm using avi-io to capture images from my tv card. Then I'm using VirtualDub to edit the avi file, followed by TMPGEnc to do the encoding. I think I'm following the right steps. I get the right video in mpeg format at the end, but it doesn't have any audio.

Retracing my steps I think it's in the capture part in avi-io that I'm not picking up the audio, as I've tried converting to a separate wav file in VirtualDub. I get a wav file output, but I can't hear anything when I play it back (maybe some of my settings aren't right).

Looking forward to any help anyone can give me.

Cheers,

Paul

[ormonde]

Load your captured AVI file into Virtual Dub (or any of it's variant programs). Go to "File" > "File Information" and post the information listed in both the "Video" and "Audio" sections of the dialog box.

[pchap]

Hi Ormonde,

Thanks for offering your help.

The video section has...

frame size 352x288
fps 25.000
length 672 frames
decompressor PICVideo MJPEG codec
number of key frames 672
min/avg/max/total key frame size 29652/35703/45759 (23431K)
min/avg/max/total delta frame size 32638/35301/38411(138K)
data rate 7140 kbps (0.07% overhead)

Audio stream...

sampling rate 11025 Hz
Channels 1 (mono)
Sample precision 8-bit
Compression PCM (uncompressed)
Layout 1 chunks (0.00s preload)
Length 298116 samples (0:27.04)
min/avg/max/total frame size 5292/5292/5292 (6K)
Data rate 88 kbps (0.45% overhead)

Cheers,

Paul

[ormonde]

Your audio file appears to be a mono 8-bit PCM WAV. Did you intend to capture in stereo? Try and open the WAV file in an audio editor program such as Cool Edit or Goldwave. You may have to modify the file somewhat to boost the audio output.

[pchap]

Hi Ormonde,

Thanks for looking further into this. From your reply and the fact that I was able to create a separate wav file that appeared had data in (but I couldn't hear it), I checked my 'multimedia' settings and discovered that I hadn't selected the TV card for recording. I've now ticked this box and can create videos with audio ok.

Thank you very much for pointing me in the right direction!

Cheers,

Paul

[ormonde]

"Thank you very much for pointing me in the right direction!"

Glad to be of help, but it looks like you solved your problem.

[pchap]

Ormonde,

That may be true, but it's often being able to discuss a problem that really gets the brain working! You have to think in a slightly different way to explain the problem to someone else, and then they might say something that makes you think of something pretty basic that you might have forgotten about!

Thanks again,

Paul