Samplerate conversion and good results?

ChrisG wrote on 8/27/2002, 12:29 AM

Hi there!

I just had to use the built in samplerate converter. Tried 44.1k to 48k.
First try: Media is 44.1k, project setting is 44.1, resample quality is always best.
Rendered as 48k wav-file. The result sounds not very hi-fi, all high frequencies are gone.
Second try: Set project setting to 48k. Now already the playback out of VV3b sounds bad.
What's going wrong here? Is the SRC algorithm that bad?
How can I get better results?

Thank you for your answer in advance!

Regards,
Chris

Comments

altphase wrote on 8/27/2002, 6:44 AM

First make sure your sound card supports 48kHz playback. If it does not (like some older ISA SB cards) than any 48kHz audio file that you play back will sound really bad because of the poor quality sample conversion of these cards.

ChrisG2 wrote on 8/28/2002, 12:32 AM

Thank you!

No that's of course not the problem, the soundcard supports 48k (RME). I tried the Shibatch converter which is considered high-end and results are much more better. So Vegas Video's SRC seems to be quite low-end :-(
Anyone can test this: http://shibatch.sourceforge.net/
Simply take a song with a lot of high frequencies (any modern pop-production should do...)

Also 48k->44,1k sounds bad with the VV SRC.

Regards,
Chris

Sonic wrote on 8/28/2002, 12:55 PM

If this is particularly noticeable on nominal material, I'd think it is more likely a bug than a problem with the actual SRC algorithm.

But the Vegas SRC in general is still slightly biased more towards performance in a multi-track environment than to what very large filters and higher order interpolations can produce. So it is conceivable that you are hearing limitations of the algorithm.

Either way it is worth a little more investigation.

If you happen to have a copy of Sound Forge 4.5 or later, I'd be interested in what happens with it's resample tool (Process->Resample) set at quality 3 or 4.

Any other details on the material and discrepancies would be welcome.

J.

ChrisG2 wrote on 8/28/2002, 2:31 PM

Hi!

Sorry, I don't have SoundForge. But I think anyone should be able to reproduce the phenomenon, since
even with material copied from compact-cassette (!), the frequency response of the sound degraded noticably after a samplerate conversion. Simply use a material with some hi-hats in it. I hear it even with consumer equipment.
I just played with the settings and I can't hear a significant difference between "Resampling Quality" "Preview" and "Best" (at least at first glance), so is it possible that VV simply ignores this setting?

Regards,
Chris