What is the native sample rate of DVDA3?

wm_b wrote on 6/4/2005, 9:45 PM
Is it 44.1k? DV audio is natively 48k but everything plays back too fast. If my sound card is set to 48k and DVDA is redithering in realtime to 44.1 and my sound card is playing it back at 48 it would speed it up. I cannot find a setting in any preferences to confirm this.

What sample rate does everyone else use to preview? Is this a common problem?

Thanks,
William

Comments

ro_max wrote on 6/4/2005, 11:13 PM
Do you render audio in DVDA? What is the preview in DVDA like, if you render your audio to AC3 in Vegas?
wm_b wrote on 6/5/2005, 12:11 AM
I've used both AC3 and PCM all from in Vegas6b. All the source audio has natively been 48k. Playback in Vages is fine. THe same file previewed in DVDA plays at the wrong speed. Same hardware settings from app to app. Preview in DVDA via pyro av link is also kind of messed up too. I suspect it has something to do with the audio issue.

I'm still trying to figure out exactly which audio format to use and when to render wit h video. The DVDA template in vegas does not include audio and I recently tried rendering them separately and joining them in DVDA but that was only marginally successfull and still played at the wrong speed and pitch. This part is still a mystery for me.

I am still in the steepest part of the learning curve with DVDA but the disks I burn play at the corrrect speed and pitch. The problem seems to be with the way DVDA interacts with my audio hardware.

Thanks, Wm.
RBartlett wrote on 6/5/2005, 12:23 AM
check you have specific drivers for your audio loaded and not generic or ones that typically work with your chipset.

I had an almost identical problem with Intel i850 AC97 sound drivers in-use and loaded but with a RealTek AC97 controller used in my specific motherboard implementation. Went to the motherboard site and downloaded the latest and the problems went. It was however a long while back and was more of a problem across the machine from any Windows app.

If it is something else, then my apologies. I can't see my guidance doing any harm though.
wm_b wrote on 6/5/2005, 1:26 AM
Thanks for the suggestion. I have a MOTU 2408 mk III audio interface with what I know to be the most recent drivers. There is no other audio hardware in my system.

I'm coming at this from an audio background. I think I might actually have a more "professional" audio setup than DVDA might be designed to work with. Most consumer audio hardware tends to default to 44.1and I'm starting to think that DVDA is expecting that sample rate from my audio interface. The problem is that I clock from an external word clock and going to 44.1 requires lots of resetting of devices all over my studio.

I cannot figure out why this part of the softaware is so ambiguous.

Thanks, wm
farss wrote on 6/5/2005, 8:00 AM
As far as I know the DVD spec requires audio at 16/48K if its PCM, I'm running out of a M-Audio Firewire 410 with no such issue however it is pretty well always set to internal sync. That could be your problem, try setting the MOTU to internal sync, I think that DVDA might have an issue during preview with an audio card running at external sync.
Does the problem still occur if you burn a DVD and play it back in a set top player?
Bob.
wm_b wrote on 6/5/2005, 2:04 PM
Well my problem is that I connot do that. I have a digital console and they must all be in synch to work. My exact audio configuration is apogee ad16x via light pipe into the motu and light pipe out into a tascam DM24. Word clock is sent from the apogee to the MOTU and then on to the DM24 with a T connector.

For my recording studio this is an excellent configuration. My mic pre's go straight into the apogee for AD conversion. Apogee to the via adat to the MOTU where the zero's and one's are sent to the host audio application. On playback the zero's and one's come from the audio host through the motu and then to my DM24 for mixing and monitoring. I have no issues with this using Vegas or Sonar 4. I set the clock for the sample rate of the project and I'm in business. No glitches.

One unsual observation is that after preview in DVDA the motu sample rate is reset to 44.1 when I have specifically checked that it was 48k beforehand. Something is up with that but I cannot disable it. Even if the work around is to reset my system to run at 44.1 This is impracticle simply because I find myself going from Vegas to DVDA and back again in the midst of putting things together. If dvd audio is natively 48/16 then why should I have to change the sample rate to 44.1 (I'm still not sure if that would solve the problem.) Seems silly not to have this as an option if in fact DVDA is natively 44.1k.

THanks,
Wm
wm_b wrote on 6/5/2005, 6:03 PM
Back in my studio this afternoon I set my clocks to 44.1k. Apparently DVDA previews 48k audio at 44.1k because the audio played at the correct speed and pitch. I have no idea why this automatic samplerate conversion is not a selectable option.

I should have added at the beginning of this thread that DVDs burned from DVDA all play the audio at the correct speed and pitch. Only preview has the problem.

Thanks,

William