Audio volume decreased at capture... ??

[Tatjahna]

I have an ATI All-in-wonder Radeon 32Mb on an Athlon 1600XP ... Audio card inboard on an Asus motherboard (audio: CMI8738) ... I am wondering if it's "normal" to have a decreased sound while capturing from S-VHS to my computer :confused: Or is it just the sound card that is ( big chance ) too cheap !!

And for now, what do I have to do to correct the sound without "chhhhhhhhh" behind, If I'm using VDub with PicVideo MJPEG for capturing, no audio compression, and then MPEG-2 it with TmpgEnc ??

Thanx in advance guys!

[Belgabor]

If the sound goes in via the Line-In input (as it usually is), its quite possible that there are two diffrent volume settings for recording Line-In (as when capturing) or listening to Line-In (as when simply watching). Check it in the mixer if there are (windows mixer or the one provided by asus (if there is such a thing))

To get away the background noise you need a audio editor (eg Cool Edit) and do some kind of denoise. I've done so before, but it tends to decrease audio quality. If the noise is pretty low, it might be possible without large effect on quality.
First you'll have to demux the audio form the capture avi ('Save WAV' in VDub), then fire up the audio editor.
In Cool Edit there are at least two functions for denoise. With one (imho the better one) you first select a range where only the noise is audible and (for best results) nothing else. Then you can gather a noise profile from this selection and with that remove it from the whole file.

If you need further info, just cry for help ;)

Regards
Belgabor

[Tatjahna]

Thanx for your reply Belgabor...

see that : http://24.200.36.170:8080/rock/screenshot_mixer.jpg

My input and output line are at the maximum!! When "watching" my video, the sound is normal... but as soon as it's captured, the sound is 15-20% of what it was before recording it.. :mad: It's incredible... I surely miss something somewhere.. I use the mixer coming with the Asus Cd ( Audio Rack or a shit like this )

Any other suggestion ? Oh the background noise is only perceptible after the capture... Before the capture, the sound is loud, clear, well.. perfect for a VHS !

Thanx again!!

Added: NOTICE: Sorry, I have captured with the new TV Software of ATI (version 7.6) ... I have now captured in VDub, and the sound volume seems normal... the fact is that now, it's full of back noise! What if I send directly the sound in my audio card line-in, instead of sending it via the S-Video connector to the ATI Card, and then sending it to the audio card ?

[Belgabor]

Added: NOTICE: Sorry, I have captured with the new TV Software of ATI (version 7.6) ... I have now captured in VDub, and the sound volume seems normal... the fact is that now, it's full of back noise! What if I send directly the sound in my audio card line-in, instead of sending it via the S-Video connector to the ATI Card, and then sending it to the audio card ?

Sounds like a VERY good idea. ;)

But its really strange you only get the noise on recording. Sounds somewhat like the onboard sound card is crap :/ or the ATI card somehow does strange things, well you'll see when u try dirctly plugging th sound into line-in ;)

Have a look at the Windoze Standard Mixer, afaik it has two diffrent settings for recording and listening. (a bit difficult to reach, if i remember correctly, you'll have to switch listening/recording in the options)

Regards
Belgabor

[Koepi]

Well, I get noise when capturing from TV or VHS as well.
You simply have to use cool-edit 2000, select "noise filters" and "save files" as capabilities for the shareware-version at startup.

Then go to the transform -> noise filters and choose "hiss reduction".

set it to max (well, that setting that leads to a line at -50dB), and adjust the floor accordingly (e.g. -20dB) with the slider below it.

After that, most of the noise should be gone.

Regards,
Koepi

[Tatjahna]

Hi Belgabor!

Hehe I only sent you the recording settings, but the incoming settings are the same for line-in :) One thing I only don't understand... In the recording section of the mixer, how come I have noticed that the little checkbox was named "select" instead of now "mute" ?? And if I remember, I was only able to set ONE of theses... (My old ISA Sound Blaster AWE64!!) Is it a "multi-channel" related new feature ??

I will try to bypass the ATI Card for the sound's input.. I don't have good quality RCA to Jack 1/8 cable, but I will try to find one ;)

Thanx again in advance! :D