Source 44khz Project 44khz ProjMed 48?

Grazie wrote on 7/15/2009, 8:37 AM
Title says it all.

But why when I import into Project Media does a 44 Audio get recognised in Right Properties as 48?

Now then, when I then render to MPG and AC-3 why is this then upped to 192? I can SEE there is an adjustment to 44 or even 48, should I do that, for the AC-3?

All this is leading to an outcome - I know it . ..

Grazie

Comments

MarkWWW wrote on 7/15/2009, 12:19 PM
> why when I import into Project Media does a 44 Audio get recognised
> in Right Properties as 48?

This should not happen as far as I am aware. I presume we are talking about WAV files here? If so, then if a WAV is sampled at 44.1kHz then it should show as such in Project Media, and via the RMB. I can't explain why you are seeing something different.

> Now then, when I then render to MPG and AC-3 why is this then
> upped to 192?

It isn't. You are confusing the sampling rate at which the original (uncompressed) audio was recorded (48kHz, 44.1kHz, 22.05kHz, etc) with the bitrate of the (compressed) Dolby Digital stream that will be generated when the audio is rendered to AC3.

> I can SEE there is an adjustment to 44 or even 48, should I do that, for the AC-3?

If you are talking about the Sample Rate box in the AC3 emcoder you should select whatever is correct for your source audio, i.e. if you are using 44.1kHz audio you would set it to 44.1kHz, if your audio is sampled at 48kHz you would set it to 48kHz, etc.

In the video world you will usually be working with 48kHz audio rather than 44.1kHz.

Mark
Grazie wrote on 7/15/2009, 12:48 PM
Mark, thanks! Me totally bad on the AC-3! Twit . . ..

The 44.1khz appears as the Match Media option. It's the audio stream of an AVI.

Grazie
Grazie wrote on 7/15/2009, 11:32 PM
The Match Media will only take note of the Video - not the Audio. So matching the project to a 48khz slice of media needs to be done manually.

Is there any, ANY, issue in having a project set with 44 instead of 48? Render? Sync? Whatever? If so please inform me . . . and if this IS the case then I would need to remember to adjust accordingly?

I understand that Vegas has this media agnostic quality - I'm not suggesting I wish to hobble this virtue. But at the same time, does this 44<>48 have any issues?

TIA

Grazie
NickHope wrote on 7/16/2009, 12:30 AM
If this is for DVD then it needs to be 48khz. 44.1khz is not in the DVD video spec.

Edit (correction): Also needs to be 48khz for going to HDV tape.

I still find it strange that most stock music suppliers supply only 44.1khz, when video work generally requires 48khz. Having said that I've never personally noticed a quality drop when resampling stock music from 44.1khz to 48khz (I haven't got the best ears though).
Grazie wrote on 7/16/2009, 12:43 AM
Sure Nick. My question is will having the Project set at 44.1 and THEN going to the DVD spec make a difference? Will the Project Settings (44.1)be ignored at the time of of the DVD file rendering?

Grazie
NickHope wrote on 7/16/2009, 1:40 AM
Oh I see. As far as I know the file rendering will take the original format of your audio (plus any effects etc. you've applied) and encode straight from that, overriding the project settings. It's not like, for example, generated media getting created (forever) at the resolution of your project settings, or like a deinterlace method having to be set in your project settings when resizing deinterlaced footage.

I'm not 100% sure on this though. Hopefully others will confirm.
Grazie wrote on 7/16/2009, 1:47 AM
So project settings are SOLELY for seeing/hearing the Project within the confines of the Project settings - no more, no less?

Grazie
MPM wrote on 7/16/2009, 9:26 AM
"So project settings are SOLELY for seeing/hearing the Project within the confines of the Project settings - no more, no less?"

IMHO... maybe.

I haven't really explored this extensively for a quite a while now -- when I started setting workflows limiting what I do in Vegas to stuff it does best, it became irrelevant. But, Vegas used to be very linear in it's programming... by that I mean it performed every step, 1 at a time, regardless the final outcome. If the frame was re-sized as 1 step, one part of whatever you were doing for example, it would perform that resize, adjust it again to preview, then go on, even if in the final step the frame was exactly the same size. This extra processing showed up in the final render. I think the project I was working on where I found this was several small video frames composited to one 720 frame. Importing the small frames was a catch 22... set the proj to 720, & they were re-sized up, then down -- set the proj to the small frames, & after compositing they were way too small. Either way the degradation from the unnecessary re-size was very visible.

I've never explored it with audio, & wouldn't think it would be the same, but I'm definitely not comfortable with the notion that proj settings are only for preview. If in doubt, check it out.
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"does this 44<>48 have any issues?"

Unrelated probably, or maybe overkill, but 44.1 vs 48, 96 etc audio... 1 issue is what your hardware uses internally -- if your hardware is 48 for example, keep it that way until the final render if/when possible. *May* want to check out when & where your hardware does conversions as well -- Creative/EMU used to have a thing where the DSP might switch from 24/96 to 16/48 & back. Not as big a deal if you're not using hardware to do anything but listen, but if you're picky you don't want to be trying to cure a problem that doesn't really exist either, even though you hear it. When you down convert you're tossing data, so just like you wouldn't want to re-size HD to SD & back again, downsample once, & only as/if needed. 1/2 of 96 = 48, which is nice & neat. Can't do that with 48 & 44.1, so, *might* want to make sure whatever's doing the down conversion does it best -- one of the things where I use Sound Forge, with a bit more control.