Plugin issues - The story so far

canum wrote on 5/4/2005, 2:32 PM
In a previous thread, H2000 reported that Senderella (and later MixBox) were causing glitches in rendered output. To level the playing field, I wrote two simple plugins... basically a send-receive pair that did the minumum amount of processing necessary to get audio from one bus to another. The experiment setup was simple:

1. Recorded a 20 second 440Hz sine in SF and saved it as a 44.1K 24 bit wav.
2. Imported the sine wav file into Vegas and set up 2 aux buses.
3. Sent the output of the sine wave audio track to Bus A.
4. Inserted "send" VST into Bus A and "receive" VST into Bus B.
5. Soloed Bus A and B and dropped Bus A volume slider to -inf.

Running with this setup will give you a clean sine tone on Bus B's output.

Then I rendered the output in a few different formats all at 44.1K, pulled them into SF and took a listen/look.

24 bit wav file - glitches all over the place, most notably on the left channel.
16 bit wav file - same as 24 bit wav file.
256K wma file - you gotta see/hear this one to believe it!
256K mp3 file - clean render, couple of small conversion artifacts.
Sony pca file - totally clean render

I guess I'd conclude from this that Senderella, MixBox and my two simple VSTs aren't the problem. Its clearly related to the way that wav and wma files are rendered although I can't tell how.

The same sine audio file sent to a single bus with a random VST processor inserted into the bus then rendered as a wav file does not display the glitching... it looks like just a bus to bus transfer causes the problem to happen.

canum

Comments

H2000 wrote on 5/4/2005, 9:39 PM
Nice work. It sounds like there is a missing piece to the puzzle. Can any Sony developers shed some light on this? Perhaps there is a limitation in the .wav rendering which would make this impossible - it would be nice if we could get some information from the source.
kbruff wrote on 5/5/2005, 5:53 AM
Hopefully we get a reply, I have has numerous issues with rendering, mostly having to do with artifacts, etc.
drbam wrote on 5/5/2005, 6:45 AM
"I have has numerous issues with rendering, mostly having to do with artifacts, etc."

kbruff: are you having rendering issues in general or mainly with bus to bus efx, VST, UAD-1 units, etc, etc. If there are general, more basic rendering problems, ie; simply rendering some tracks with basic efx, envelopes, etc., then obviously Vegas 6 would be completely non-useable. Could you be more specific in what your referring to here?

Thanks,

drbam
canum wrote on 5/5/2005, 6:50 AM
I hope there's an answer as well. Using the setup I described in the first post, the problem is relentlessly reproducible and may actually point someone who knows the internals of the wav/wma renderer in the right direction. Using a characterizable waveform like the sine I used shows a definite pattern to the problem. That seems like the first step in getting a handle on what's wrong.

canum
Spheris wrote on 5/5/2005, 7:42 AM
Unofficially, Dave Hill and I discussed this issue in the earlier year concerning a side issue in vegas 5 that was outstanding (and supposed to be addressed in 6 but obviously was not) I'm sorry, but I will not go into the specifics of what the issue was, per my agreement with Hill about it

The workaround proposed was aif or pca renders (which apparently also re enable the bussing assignments backward compatible with vegas 4 that so many were so disappointed with (though I cannot say I ever tested it for myself)

However the render to aif/pca does apparently remain stable - despite the other exports remaining corrupt in some form. I know it's not much in the way of a fix - but it is an alternate if you have to tolerate till either a fix or surrender appears.
drbam wrote on 5/5/2005, 8:06 AM
"However the render to aif/pca does apparently remain stable - despite the other exports remaining corrupt in some form. I know it's not much in the way of a fix - but it is an alternate if you have to tolerate till either a fix or surrender appears."

So someone PLEASE help me to understand this. You seem to be saying here that rendering to wav files in both Vegas 5 & 6 results in "some form" of corruption?? I REALLY hope and pray that I'm interpreting this incorrectly because the obvious implications would be disastrous!! Clarification please!

Thanks,

drbam
canum wrote on 5/5/2005, 8:16 AM
Hi drbam,

It looks as though wav files rendered without any bus to bus transfers are okay... at least that's what the simple experiment I did yesterday seemed to show although I didn't minutely inspect the results for minor deviations from one of the formats that always seem to render properly (pca, hi-res mp3). I can certainly do that, but it would be hard to discern whether or not the differences were a problem or a "normal" artifact of the rendering process.

canum
kbruff wrote on 5/5/2005, 10:39 AM
With the UAD1 card, ever since Version 4, I have not stepped up to V6.
Thanks -
Kevin