Mixing Audio Sample Rates? (48 kHz & 44 kHz)

MadMaverick wrote on 9/14/2016, 8:54 PM

I've noticed that all the video I shoot records sound at 48 kHz, while all the songs/sound effects that I acquire are 44 kHz. Vegas Pro 13 will list them as being 44,100 Hz, while right clicking the file on my computer will list them as being 44 kHz... which makes me wonder the difference between Hz and kHz?

Also, on some video/audio files I'm unable to see what the audio sample rate is. I use to have this program called Media Info, which I assume would tell me. I no longer have this on my computer. Anyone know where I can download this? It seems like I found out about it on here.

I was wondering if it was okay to mix audio that are different sample rates? Would there be much of a difference between 48kHz and 44kHz? I remember hearing this guy on YouTube named The Frugal Filmmaker talk about issues with audio drifting. He recommended recording sound at 48kHz. It does seem like my audio will drift at times.

If it's best to not mix different audio sample rates, then I suppose I should convert them all to be the same. Would one be preferable to the other? It'd probably be easier to convert the songs/sound effects to 48 kHz. I guess I could just do that with Vegas.

Although, I'll usually clean up my recorded audio in Audacity before re-importing it to Vegas. Could I convert it using Audacity?

Any tips or info would be appreciated.

Comments

Former user wrote on 9/14/2016, 9:31 PM

Normally audio for video is at 48k. Cd audio was always at 44k. It is okay to mix audio, but if you sync to an audio track (such as shooting a music video) you should use the same audio file through the whole process and to minimize the possibility of sync drift, convert it to 48k. (the K stands for 1000, so 44khz is the same as 44,000hz. They just drop the 100 for conversation.

You will find you are more likely to have issues with an MP3 file than a WAV file. So I would suggest converting all source audio that is not locked to a video, to WAV. Avoid MP3s on the timeline.

NickHope wrote on 9/14/2016, 10:59 PM

For MediaInfo, see #6 in this post: https://www.vegascreativesoftware.info/us/forum/why-does-my-rendered-video-look-bad-quality-troubleshooting-basics--103361/

I have often mixed 48k and 44k files of various formats on the Vegas timeline and never had a problem. I let Vegas do the upsampling to 48k if I'm making a DVD, or the downsampling to 44k if it's for the web. The last time I tested, YouTube would resample 48k to 44k, but they are now recommendin g 96k or 48k upload so perhaps they have stopped resampling. A short test would confirm. Even if they do now deliver 48k, if I had a 50/50 mix of 44k and 48k on my timeline I would probably downsample the 48k to 44k rather than upsampling the 44k to 48k. I personally can't hear the difference between audio resampled either way between those 2 frequencies by Vegas.

I think resampling quality in Audacity or Vegas would be pretty much identical. Vegas was an audio program first and makes a fine job of this stuff.

rraud wrote on 9/15/2016, 9:37 AM

As you probably know Vegas can have different sampale rates on the TL (or same track) without issue (not so with all NLEs though). The render sample rate setting is in the audio propertes dialog which is more important There's very little quality difference (and wouldn't be audible) between 44.1 and 48kHz. 48k has a slighty wider bandwidth (nyquist freqency 24k vs 22.5kHz.) Music recording studios however usually record @ 96k or 192k these days, usually the same for S/FX. Dialog is normally recorded at 48K/24 bit .. even on blockbusters.