Feature Film Bit & Sample Rate

[Ryan Krickow]

I'm planning on recording the audio for an independent feature film shooting on HD at 23.98fps at 24bit 48kHz. I'm wondering what the most common bit and sample rate are for most feature films both independent and blockbuster. Is 24bit 48kHz standard? Should I be recording at a different rate? Any references to theatrical films would really be appreciated. Thanks!

[Bill Ravens]

I think this is a $64M question.
And the answer depends on whether you're going back out to a cut film final or a digital image transferred to film final. You'll probably edit a 23.98 NDF digitized proxy and sync the sound to that file. In that case the sound should be 23.98 NDF.

It also depends on what kind of sound recorder you're gonna use. The older DAT recorders asked the op to set the frame rate. The newer CF card recorders don't care. Either way, 48000Hz 24 bit seems to be the "standard".

[Jon Fairhurst]

Originally Posted by Bill Ravens

Either way, 48000Hz 24 bit seems to be the "standard".

Agreed.

If you want higher capture rates, choose an even multiple, like 96 kHz or even 192 kHz. It makes down-sampling to 48 kHz cleaner than, say going from 88.1 kHz. Personally, 48 kHz @ 24 bits is good enough for my money.

There are only two situations where I would recommend the higher sample rates: 1) you are making something for audiophiles and want the snob factor, or 2) you plan to playback the sound in slow motion ("Noooooooo...", screams the victim), and you don't want the sound to be any muddier than it need be.

[Ryan Krickow]

Do either of you happen to know what most films that are released in the theater use?

[Steve House]

Originally Posted by Ryan Krickow

Do either of you happen to know what most films that are released in the theater use?

Most these days are recorded 24bit at 48 or 96kHz. Final delivery is 16bit 48kHz

[Ryan Krickow]

Sorry to keep prying but can you name off the movies that you are referring to as well as their bit and sample rates? I'm really having a hard time finding this information on the internet. IMDb doesn't have this kind of detailed audio data and none of the audio sites that I visit seem to mention this information either.

[Jim Boda]

Originally Posted by Ryan Krickow

I'm planning on recording the audio for an independent feature film shooting on HD at 23.98fps at 24bit 48kHz. I'm wondering what the most common bit and sample rate are for most feature films both independent and blockbuster. Is 24bit 48kHz standard? Should I be recording at a different rate? Any references to theatrical films would really be appreciated. Thanks!

What editor are you using to cut together the film?

Here is a frame rate chart for Avid Media Composer (pdf)... http://www.aaton.com/files/avid-recording-rates.pdf

Notice at certain recording rates and project types, the Sample rate could be either of these:
48000
47952
48048

[Ryan Krickow]

I'm using FCP 6.

[Wayne Brissette]

Sample rates for most features are done at 48 kHz. There are some exceptions where there will be some pulling up or pulling down and you use 48.048 or 47.952 kHz but usually this is when there will be some conversion (NTSC / PAL).

I'm assuming you are doing your own post production. If not, you will need to verify with the post house/telecine what time code and sample rate they want. It's actually very rare to run 96 kHz sampling for film unless you are doing some nature documentary and capturing wild sound.

Ryan, if you are looking for a list of movies and what they used, look up Jeff Wexler on IMDB. Jeff uses a Deva V and runs it at 24/48 for all his projects. You can also look up Ron Scelza on IMDB, he also uses the Deva V and runs it at 24/48 for his projects.

Wayne