16-bit vs. 24-bit (48 kHz)

[Jeremy Garchow]

The only thing I would do is covert your 44.1 to 48k 24 bit. Don’t worry about the other 48k 16 bit. 16 bit and 24 bit files play just fine in FCP.

Jeremy

[Jbwjr22]

Yes, FCP plays everything fine, even the 44.1k music.

It’s the OMF export that concerns me. Should I select 16-bit or 24-bit (48k) for the OMF export, and what difference would choosing one vs. the other make if I’ve got both 16-bit and 24-bit (48k) audio sources? Is it better to upsample a 16-bit source to 24-bit, or the other way around?

Thanks again.

JW

[Jeremy Garchow]

24. Keep the higher quality stuff @ high quality, just like video.

Jeremy

[Jbwjr22]

I’ll be mastering to DigiBeta, which if I’m not mistaken is only capable of 20-bit, and I think the SD broadcast spec is only 16-bit. So 24-bit audio would need to be downconverted at some point.

Would the audio from my BetaSP video sound any different during SD broadcast if captured at 24-bit then downconverted to 16-bit, as opposed to capatured at 16-bit in the first place and never converted?

[Jeremy Garchow]

Not to my ears, but I’m a video editor.

Might be best to get an audio guy on the horn.

[Gordon Gurley]

It’s best to use the highest bit rate when you are manipulating the audio (ie mixing, EQing). Even if the original was 16 bit, it’s best to use 24 bit processing. Yes, Digibeta is 20 bit, bit it’s much better to go 24 to 20 than 16 to 20.

Gordon Gurley
Director of Operations
Stanford Video

[Jbwjr22]

What, if any, modification is made to audio during OMF export? As mentioned previously, I have three different types in my project:

48k/24-bit (from BetaSP video)
48k/16-bit (narration – .wav files)
44.1k/16-bit (original music – .wav files)

If I specify 48k/24-bit for my OMF export, does this modify the narration and music (which aren’t 48k/24-bit) during the export? I don’t have ProTools, so I’m unable to see what’s really happening during the OMF export. (Or am I?)

I’ve also heard suggestions of going ahead and converting my music to 48k. Would it be better for me to do that, or let my audio mixer do that in ProTools?

Thanks.

[Gordon Gurley]

Just guessing here, but FCP probably converts the audio on OMF export. Converting 16bit to 24 is a non-issue, it’s only adding zeros. Converting 44.1 to 48 is a slight issue. Pro Tools may do a better job of this than FCP, but we’re splitting hairs here.

Gordon Gurley
Director of Operations
Stanford Video

[Jeremy Garchow]

[Gordon Gurley] “but we’re splitting hairs here. “

I totally agree. I’d convert the 44.1 to 48 in iTunes or compressor and don’t worry about the bit depth so much.

What’s your audio guy say?

[Lee Grainge]

Waah! Don’t convert in iTunes!!! I would never do such a thing.

I work with sound in the CORP and Film Worlds.

Get a list together of the sound KHZ and BIT differences, and let the PT guy/girl sort out any changes needed for you. (I think you have it already, your list) The music should be written in the same frame rate as the sound edit should of been.

Have the sound at 48K 24BIT – As someone else said already it’s better to go down than up. Going up will destroy some of the quality within the audio track. The OMF should be set at whatever rate you are in in your session. The final out-come for TV (and high end sound/visual system users) should (in my eyes) be the highest possible.