Is it possible to capture analog audio at 48Khz?

[Zippy72]

Hi Guys,
Currently I suffer from the slightly metallic sound when converting an analog capture to DVD. Apparently this is to the capped audio being at 44.1kz and then converted to 48khz.
So the simple question is, can I capture directly to 48khz? I use iuVCR at the moment, with a Terratec Cinergy TV card to capture.
Thanks in advance

[SLK001]

An up-conversion should not give you this sound. It probably was there in the original, also. Try another program to do your up-converting.

Also, most sound cards today can capture audio at at least 48kHz. Many go even beyond this.

[Zippy72]

OK thanks SLK.
I don't suppose you know the option to try 48khz in iuVCR do you (sorry if that's a stupid question)?

FYI, The sound problem I mention isn't really that bad, but it only occurs if I convert to DVD, the sound is great if I convert the same file to VCD or SVCD. Basically it sounds as if people are speaking through an amplified source (kind of like a megaphone, but not as severe). I just assumed that it was the 44.1 -> 48 thing, but do you think it could be something else? Could it perhaps be that I need a better template in TMPGEnc.

Thanks

[omega_weapon]

Hi guys. Forgive my ignorace, but, what is the diference betwen 44.1 and 48khz ?
quality? high tone? ???

[SLK001]

Theoretically, 48ksps is able to give you frequencies of up to 24kHz, while 44.1ksps is able to give you up to 22.05kHz (Nyquist rate is sample freq / 2).

I would convert from 44.1 -> 48 ksps using a dedicated audio program (I use Cool Edit 2000).

As for iuVCR, I'm not familiar with that program, so I can offer no guidance.

[Zippy72]

Thanks again SLK, I think a different audio encoder is definitely the way to go.

omega_weapon,
I'll try to answer your question, though I'm not really an expert (if any of this is wrong, anyone feel free to correct me).

44.1 and 48 khz is the frequency that the audio is sampled at, ie 44,100 or 48,000 times a second respectively. 44.1khz is the standard for CD, VCD etc and 48khz is the standard for DVD (slightly higher quality). My problem was that I was capturing at 44.1khz (CD quality) and TMPEGEnc was "up-sampling' (if that's a word) to 48khz because I was encoding to DVD, and there was a noticeable difference in the audio. So I assumed the frequency change was at fault.

Hope that answers your question a bit, but if you want it any more technical than that, you'll have to ask SLK001.

[Riccardom]

If i'm not wrong, IUVCR should show a list of sampling frequency that your audio card is able to record.
My SB Live 1024 can record up to 48 KHz.
I think so because all AVI capture programs (AVI_IO, VIDCAP, AMCAP) do the same, when you choose PCM, except ATI MMC (still 7.6).
Hope it helps

Riccardom

[SatStorm]

Just to inform you that you can grabb direct to 48000khz with Virtualdub.

Tip: When you upsample with tmpgenc, it is better to use an external converter for this. SCMPX is excellent for this task and freeware

[Mirror_Image]

ATI MMC 7.7 now has 48kHz audio capture (and about time, too).

[Dragonsf]

If i'm not wrong, IUVCR should show a list of sampling frequency that your audio card is able to record.
My SB Live 1024 can record up to 48 KHz.
I think so because all AVI capture programs (AVI_IO, VIDCAP, AMCAP) do the same, when you choose PCM, except ATI MMC (still 7.6).
Hope it helps

Riccardom

Doesn't the SB Live use the EMU10k chip? If so, you can only sample at 48Khz.

[Zippy72]

Thanks guys.
I guess it's down to my soundcard then. I'll try and check it out over the weekend and let you know.
Cheers

[Zippy72 at home]

Well I tried it (the option in iuVCR is really obvious, so sorry for the silly question), but my soundcard, which is crap, doesn't support it.
Oh well, is there an idiot's guide to using an external decoder in conjunction with TMPEGEnc anywhere on this wonderful site?
Cheers

Zippy