any way to edit 32-bit floating point audio in fcp without rendering?

[Michael Gissing]

FCP doesn’t handle floating point audio files. It has to have 16 or 24 bit fixed, 48khz. The FCP sequence can be set to 32 bit float but that is only how FCP does its internal audio processing.

[Jeff Meyer]

You should be able to build a Compressor preset that will do a video pass-through and then dial in the audio settings you want.

[Douglas Glover]

Hi,
Thanks for the advice. Is there a way to do a video pass through without altering the video so that it just alters the audio and doesn’t take so long?

I’ve tried using the same video settings as the quicktime in compressor and just altering the audio but it still seems to take 3 hours per video. This means that it’s obviously doing something to the video instead of just the audio.
Thanks

Douglas Glover
http://www.douglasglover.com

[Jeff Meyer]

Going back I see a pass-through for the audio, but not for the video.

That siad, if it’s taking three hours I’m hesitant to believe that your settings are the same unless you’re using a long GOP codec like H.264 or mp4 or the videos are three hours long. If you aren’t working in a RT codec like any member of the ProRes family or the DV family it would be wise to switch to such a codec along the way.

Alternatively, you could do a pass in Compressor with the video disabled, then reconnect to the audio re-encoded in Final Cut. This isn’t an ideal situation, but it would work quickly if transcoding is taking too long.

[Rafael Amador]

Does exist something like “32b FP” audio?
Floating point is a fashion of processing at 32 bits depth, but on my advice do not exist “32bFP audio files”.
FC renders audio at 32b FP, but write them at 8,16 or 24b.
I think this is all a misunderstanding with 32Khz files.
Set your FC sequence to 32Khz instead of 48Khz.
rafael

http://www.nagavideo.com

[Michael Gissing]

Yes Rafael, there is a 32 bit float audio file format. In a program like Audcaity, Nuendo and Samplitude it is a file record format option.

[Rafael Amador]

[Michael Gissing] “Yes Rafael, there is a 32 bit float audio file format. In a program like Audcaity, Nuendo and Samplitude it is a file record format option.”
Hi Michael,
Those programs can sample and process at 32bFP, but no one of them put out any kind of file/codec/format that is 32bFP.
FP is about wider dynamic range and even if possible, they make no sense in an audio track of a video clip.
In Video/graphics, FP is used to keep off-specs levels.

[Douglas Glover] ” As I’m finding now, FCP (version 7.0.3)
only allows 24-bit floating point in the sequence presets. “
FC only allows 8, 16 and 24b samples at 32, 44,1, 48, 44,2 and 96 Khz. Nothing related with Floating Point here.
rafael

http://www.nagavideo.com

[Walter Soyka]

[Rafael Amador] “FP is about wider dynamic range and even if possible, they make no sense in an audio track of a video clip. In Video/graphics, FP is used to keep off-specs levels. “

Floating point has three big advantages for visuals:

• Large dynamic range (the difference between black and white)
• Values above and below clipping (values brighter than white and darker than black, very useful when chaining effects)
• Very high precision (leading to reduced quantization or rounding errors, also useful when chaining effects)

With fixed point or integer math, the gap between any two adjacent numbers is constant. With floating point, the gap between any two adjacent numbers is proportional to the number itself — about ten million times smaller than the number.

In other words, large numbers are spaced further apart, but small numbers are spaced closer together, giving you incredible precision in the lower/darker/quieter end of the range.

I’m not an audio whiz, but I imagine all these benefits would be as important with audio signal processing as they are with video.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events

[Rafael Amador]

As usual you nailed it down Walter.

“In Video/graphics, FP is used to keep off-specs levels. “”
When i wrote that I was thinking about what i consider the most interesting feature of FP for my workflows.
When I use NeatVideo in FC before sending to Color, thanks to the FP capability of FC, theres is not any signal clipping. In that case the 32bFP process ends up on a 10bYUV file with the highlights untouched.

[Walter Soyka] “I’m not an audio whiz, but I imagine all these benefits would be as important with audio signal processing as they are with video.”
I agree, but my point was about “Floating Point” formats, or codec or files.
I understand Floating Point as way of making maths, but not an option for storing data.
However I’m not a sound expert neither.
rafael

http://www.nagavideo.com

[Michael Gissing]

Hi Rafa. I also checked another software program – Voxengo R8Brain. It is a batch sample rate and bit depth file converter. In output file options it offer 16, 24, 32 floating point and 64 floating point.

https://www.voxengo.com/product/r8brain/

I don’t understand how a file can be floating point either but they are file options. Of course FCP cannot import 32 or 64 bit audio files but they do exist.