Sample rate changed

Paulo Ribeiro wrote on 6/5/2009, 5:01 AM
This is the first time i use DVD Architect so it may be possible that i'm doing something wrong.

I have this new DVD project where i imported mpeg2 files for menu and main movie. Audio is AC3. Sample rate is 48 KHz. When i hit play they both run faster than normal (sound and image). If i change my soundcard settings to 41 KHz everything runs normal... but the sound files are 48 KHz (?!).

This is definitelly not normal... or is it? The project settings are correct so, what am i doing wrong? Sugestions anyone?

Thank you in advance for your support.

Comments

Steve Grisetti wrote on 6/5/2009, 5:40 AM
Was this MPEG/AC3 output by Vegas or from another source?

In any event, go to your File menu and select Optimize DVD.

The green checkmarks on this screen tell you what files will not be re-encoded by the program. Your video should definitely have green checkmarks next to it.

If you are using optimized audio for your source files, they should have green checkmarks also. If not, select the file and look at the Audio for it. Set the audio to output at AC3.

It seems strange that the sampling rate would have any effect on the speed the audio plays.
Paulo Ribeiro wrote on 6/5/2009, 6:51 AM
Hello Steve Grisetti,

Yes, the MPEG/AC3 output was from Vegas Pro 8.

Optimize DVD shows that the menu video needs recompression because of the graphics included, wich is normal. The film video has a green checkmark. Both menu and film audio have green checkmarks.

It is not completelly strange that the sample rate has effect on the speed the audio plays. Consequentlly, it will change the sound pitch. So, If i have a 48 KHz audio file and set my card sample rate to 41 KHz the audio will play "slower" producing a lower pitch. In the oposite, if i have a 41 KHz audio file and set my audio card to 48 KHz the file will be played "faster" producing a higher pitch. As a consequence, the video will also change its reading speed.

So, i decided to replace the AC3 sound files with PCM 16 bit 48 KHz WAV sound files. The same thing hapened. The strange thing is why does 48 KHz files , in a system with a soundcard set to 48KHz, will play faster than they should ? Strange is why will they play properlly only if i set the soundcard clock to 41 KHz ?

The same files played in Vegas or any other video or audio software will play properlly !!!

This one i'm not able to figure out... yet. Can you ?

Anyway, thank you for your support.
johnmeyer wrote on 6/5/2009, 7:33 AM
Don't render in mono. You MUST render using stereo.
Paulo Ribeiro wrote on 6/5/2009, 10:24 AM
Hello johnmeyer,

I didn't rendered in mono. I allways render final mixes in stereo.
Paulo Ribeiro wrote on 6/5/2009, 2:07 PM
After having rendered the whole movie to burn on a DVD, the vob files generated played just fine using Power DVD.

I'm going to burn the DVD now and see how it behaves on a hardware DVD player.

So, at this point it seems it's an issue related with DVD Architect when playing the files on its timeline. Why ? That is a good question.
Paulo Ribeiro wrote on 6/5/2009, 4:07 PM
Ok, the DVD works fine everywhere.

However, DVDA keeps changing the files reading on its timeline. With the soundcard sample rate set to 48KHz, files keep being pitched up as if they were 41 KHz, but they're not, they're 48KHz. When the soundcard sample rate is changed to 41 KHz i get normal reading (?!).

Under Options, Preferences, there is no Audio Device panel as a way to check for audio settings, so...

Sugestions anyone ?