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View Full Version : Why do my QT outputs have 32-bit audio?



Andrew Young
01-25-2010, 11:58 AM
Audio was recorded to the Camera, which I believe is 24 bit. Audio was also recorded to 24 bit wav files with matching TOD TC (jammed with camera).

When I render dailies out of RocketCineX they show up as having 32 bit audio, which the Avid that needs to import them does not like. This happens regardless as to whether I am using the camera audio or am auto syncing to the wav files.

Deanan, or anyone else, any idea why this is happening and how I can fix it? This also happens when I use RedcineX.

Jordan Livingston
01-28-2010, 08:52 PM
I too have this issue and am not sure what it means... The 32-bit audio plays fine without a render on my 24-bit audio timeline, so I thought perhaps it was merely a metadata issue. Would love to know the answer to this...

- Jordan

Andrew Young
02-01-2010, 12:09 PM
I'm guessing that it is indeed a metadata issue, however, it's enough to prevent my client's Avid from being able to import the footage. Frustrating...

MichaelP
02-01-2010, 10:00 PM
Are you transcoding directly to MXF files or QT?

Michael

Andrew Young
02-02-2010, 05:20 AM
Are you transcoding directly to MXF files or QT?

Michael

Thanks for chiming in Michael. I'm making QTs rather than MXFs for 2 reasons: 1) The production is off-lining in SD and last time I checked RocketCine did not offer an SD export option in MXF, and 2) the production is cutting at 29.97 (TV doc, Red intercut with Varicam) and would not be able to import 24 fps MXFs into their project even if I could make them. They're working on a legacy Media Composer - OS9 if you can believe it. So I'm making SD Photo Jpeg QTs which they can import via Metacheater. It's slooooow. (Michael, If you can think of a better codec for faster import or any any other ideas I'd love to hear them.) Anyway, everything was working fine until we hit clips with audio. The Media Composer gives and error on import because of the 32-bit audio, so now I'm re-compressing those files in compressor to get to 16-bit audio. A real pain. (Autosync with audio files wasn't working for them, apparently because the frame rates/TC were different once in Media Composer.)

Any thoughts welcomed.

MichaelP
02-02-2010, 08:56 AM
OK, this makes sense. The 32 bit audio support was fixed on MC 3.5 - anything earlier would run into this issue. REDrushes added an option to make Avid compatible audio for the earlier versions of Media Composer.

I need to finish my quick guide for SD workflows which combined MPEGstreamclip and MetaCheater for the ALE. I create the Avid QT wrapped compatible media from there. But your bigger issue is that none of these applications create SD media that has proper 2:3 pulldown inserted in order to edit at 29.97...

How are you getting the 23.976 frames to be 29.97? Is compressor adding pulldown?

Michael

Andrew Young
02-02-2010, 09:20 AM
How are you getting the 23.976 frames to be 29.97? Is compressor adding pulldown?

On import, Media Composer is adding a bastard pulldown to the QT clips for the offline. Metacheater is doing the 24 -> 30 TC conversion for the ale file. For on-line, in-take R3Ds will be pulled and transferred to HD tape to get a proper pulldown. Pain in the butt, but I know of no good way to render in a pulldown in the file-based world, outside of AfterEffects, perhaps. Any thoughts?