Could this be considered a bug? Not sure

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Level 3

945 points

Could this be considered a bug? Not sure

I had a voice over session that was accidently recorded in 44.1kHz and when bouncing out the final broadcast mix I used sample rate conversion to take to 48k for the editor, who just drops the audio mix (LR) into his Final Cut session.... Unfortunately, the peak levels are messed with using sample rate conversion... We're talking about 1 to 1.5 db too hot, which is pretty important when talking broadcast.

It meters just perfectly on the realtime bounce, but if you open the resulting file in QT it plays out hotter.
I have also tried bouncing out at 44.1 and just using the realtime conversion in FCP, but the result is the same... too hot by about 1 to 1.5db.

Should SRC retain the levels correctly, or is this normal behavior?

Cheers,
Matt

2.8Ghz Octopooter/PMG5 Dual2/MBP 2.2 15"/ www.mattrixx.net, Mac OS X (10.5.5), Logic/MelodyneST/Live/NIKomplete5/RMEff800/DUET, other bits and pieces. :-)

Posted on Nov 5, 2008 5:02 PM

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Answer 1

mattrixx Author

Level 3

945 points

Nov 5, 2008 6:10 PM in response to mattrixx

Upon a little further investigation etc... Compressor, QT Pro, Pro Tools all do the same thing.

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Answer 2

Nov 5, 2008 6:50 PM in response to mattrixx

Have you checked the normalize feature in the bounce dialogue?

Eddie

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Answer 3

mattrixx Author

Level 3

945 points

Nov 5, 2008 7:38 PM in response to Eddie Eagle

Nope.... and it's not that drastic. We are talking about the difference between -9dbFS (the peak level I want nothing to go over) and -7.9dbFS (where I will get into trouble with broadcasters)

I hadn't noticed this before, as I always do the tv stuff at 48kHz, but I'd made a mistake and recorded the session at 44.1kHz, so thought I would try and convert in the bouncing process.

It appears that the problem is globally stitched up with Quicktime, as I can repeat the problem by opening a properly recorded 48kHz file in QT and playing while the overall audio system is at 44.1kHz, therefore invoking Quicktimes ability to sample rate convert on the fly.... it changes the level doing so.

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