Slow motion and sync audio

Higher sample rate may not make a difference. Unless you are not correcting
the pitch on the subsequent slow down. (like for a special low frequency
dream like sound effect) where you are playing back at half speed.
Directors have this harebrained Idea every now and then. And it rarely works
with any of the original sound.
Especially with dialogue. A 25% slow down of dialogue makes everyone sound
either like Barry White (if you don't pitch correct)
or Really drunk. (if you do pitch correct) Most Sound manipulation software
or hardware (eventide etc) will probably be happier with the more standard
48k. Since pitch correction takes time slices of the audio and repeats
them; the coarseness of the time slicing is far more audible than any subtle
difference between 48k with interpolation or 96k downsampled then
interpolated.. Either way sound samples have to be duplicated.

Usually they just re-record the voices (ADR) at a slower pace to sound more
natural and stay in sync.
I would just record 24 bit 48k like normal and let them play with it in
post.
----Courtney



"Fred Salles" wrote in message

> Sorry forgot to say that here the demand is quite unconventional: there
> is
> dialog and the director wants the words to be in sync, that means slowed
> down like the picture.
>
> I figured as the audio file is going to be time-streched down for more
> than
> 30%, higher sample rate would give better result.
> FredS
>
> "Fred Salles" a écrit dans le message de
> 471f4eda$0$8018$426a74cc@news.free.fr...
>> Hello all,
>> I will have to shoot a scene soon where the director wants a light
>> slow-mo
>> effects. The camera speed (35mm) will then be 36 i/s i have been told.
>> (normal speed eitheir 24 or 25, don't know yet)
>> I think I am going to record this scene in 96 kHz on my 744T and keep
>> the
>> TC at 25 (or 24) as it won't then be used for sync.
>> Recording 96k should preserve better audio quality after the push up/down
>> process I figured.
>> My first question is should I keep recording everything else in 96k or
>> should I go back to 48k for the normal speed shots and wild sounds?
>> The other question is: as the editor needs picture and sound at normal
> speed
>> and in sync, and at 48k, in his/her Avid, the time strech should take
> place
>> during sync step. Is it common practice for sync studio to handle 96k
> sample
>> rates, and do weird time strech?
>> (don't have access to post details yet).
>>
>> Any other suggestion welcome
>> Thanks
>> FredS
>>
>>
>>
>
>
 >> Stay informed about: Slow motion and sync audio 

Most Cameras get so loud at rates beyond nominal it´s pretty much
impossbile to record usable sound unless you´re recording car crashes
etc.

Also time-stretching more than 2-3 frames longer create extreme heavy
artifacts that are close to robot-voices. You only option would be a
regular vari-speed process wich will slow down the sound like an
analogue tape would. A time-stretch from 24 to 36 will create very
heavy arifacts using common plug-ins.

96Khz when vari-speeding the track down no doubt. Expect no magic when
time-stretching (lengthening the clip while preservig the pitch)

Adrenaline AVIDs handle 96k fine.


frank.



On 24 Okt., 16:04, "Fred Salles" wrote:
> Hello all,
> I will have to shoot a scene soon where the director wants a light slow-mo
> effects. The camera speed (35mm) will then be 36 i/s i have been told.
> (normal speed eitheir 24 or 25, don't know yet)
> I think I am going to record this scene in 96 kHz on my 744T and keep the
> TC at 25 (or 24) as it won't then be used for sync.
> Recording 96k should preserve better audio quality after the push up/down
> process I figured.
> My first question is should I keep recording everything else in 96k or
> should I go back to 48k for the normal speed shots and wild sounds?
> The other question is: as the editor needs picture and sound at normal speed
> and in sync, and at 48k, in his/her Avid, the time strech should take place
> during sync step. Is it common practice for sync studio to handle 96k sample
> rates, and do weird time strech?
> (don't have access to post details yet).
>
> Any other suggestion welcome
> Thanks
> FredS
 >> Stay informed about: Slow motion and sync audio 

Thanks Courtney and all,

At the end the director decided to go back to normal 25 i/s after I
explained that they must definitely speak to post prod to get confirmation
about the possiblity or not to do it, and more so when I could explain
clearly to him how the voice would sound.
I did some test on my own with my old Cool edit Pro just to get a rought
idea: it sounded like a corsican on booze ;=)
Sorry for the stupid french joke but it worked on the director...

Always good to get some brain stimulation though.

FredS



"Courtney Goodin" a écrit dans le message de
htSTi.301$%Z2.66@nlpi068.nbdc.sbc.com...
> Higher sample rate may not make a difference. Unless you are not
correcting
> the pitch on the subsequent slow down. (like for a special low frequency
> dream like sound effect) where you are playing back at half speed.
> Directors have this harebrained Idea every now and then. And it rarely
works
> with any of the original sound.
> Especially with dialogue. A 25% slow down of dialogue makes everyone sound
> either like Barry White (if you don't pitch correct)
> or Really drunk. (if you do pitch correct) Most Sound manipulation
software
> or hardware (eventide etc) will probably be happier with the more standard
> 48k. Since pitch correction takes time slices of the audio and repeats
> them; the coarseness of the time slicing is far more audible than any
subtle
> difference between 48k with interpolation or 96k downsampled then
> interpolated.. Either way sound samples have to be duplicated.
>
> Usually they just re-record the voices (ADR) at a slower pace to sound
more
> natural and stay in sync.
> I would just record 24 bit 48k like normal and let them play with it in
> post.
> ----Courtney
>
>
>
> "Fred Salles" wrote in message
>
> > Sorry forgot to say that here the demand is quite unconventional: there
> > is
> > dialog and the director wants the words to be in sync, that means slowed
> > down like the picture.
> >
> > I figured as the audio file is going to be time-streched down for more
> > than
> > 30%, higher sample rate would give better result.
> > FredS
> >
> > "Fred Salles" a écrit dans le message de
> > 471f4eda$0$8018$426a74cc@news.free.fr...
> >> Hello all,
> >> I will have to shoot a scene soon where the director wants a light
> >> slow-mo
> >> effects. The camera speed (35mm) will then be 36 i/s i have been told.
> >> (normal speed eitheir 24 or 25, don't know yet)
> >> I think I am going to record this scene in 96 kHz on my 744T and keep
> >> the
> >> TC at 25 (or 24) as it won't then be used for sync.
> >> Recording 96k should preserve better audio quality after the push
up/down
> >> process I figured.
> >> My first question is should I keep recording everything else in 96k or
> >> should I go back to 48k for the normal speed shots and wild sounds?
> >> The other question is: as the editor needs picture and sound at normal
> > speed
> >> and in sync, and at 48k, in his/her Avid, the time strech should take
> > place
> >> during sync step. Is it common practice for sync studio to handle 96k
> > sample
> >> rates, and do weird time strech?
> >> (don't have access to post details yet).
> >>
> >> Any other suggestion welcome
> >> Thanks
> >> FredS
> >>
> >>
> >>
> >
> >
>
>
 >> Stay informed about: Slow motion and sync audio 

Is there a speciffic program you have in mind?

frank.

On 26 Okt., 17:36, Jay Rose wrote:
> On 2007-10-25 16:28:18 -0400, wildt®ax said:

> Frank,
>
> Check out the Phase Vocoder, a totally different process from what's
> normally used in musical pitch/time shifting (even the
> formant-corrected kind). You can get 2x or 3x when done right. Sounds
> like the talent is on drugs, but no metallic artifacts.
>
> --
> Jay Rose CAS
> tutorials and other sound goodies at dplay.com
> email is "jay@" plus the dot-com in the previous line.
 >> Stay informed about: Slow motion and sync audio 

On 2007-10-25 16:28:18 -0400, wildt®ax said:

> time-stretching more than 2-3 frames longer create extreme heavy
> artifacts that are close to robot-voices. You only option would be a
> regular vari-speed process wich will slow down the sound like an
> analogue tape would.


Frank,

Check out the Phase Vocoder, a totally different process from what's
normally used in musical pitch/time shifting (even the
formant-corrected kind). You can get 2x or 3x when done right. Sounds
like the talent is on drugs, but no metallic artifacts.



--
Jay Rose CAS
tutorials and other sound goodies at dplay.com
email is "jay@" plus the dot-com in the previous line.
 >> Stay informed about: Slow motion and sync audio 

On 2007-10-26 11:50:39 -0400, wildt®ax said:

> Is there a speciffic program you have in mind?...
>> Check out the Phase Vocoder,

Last time I had to do any, I had a G-5 Mac available so I used
SoundHack under Classic. There are probably more elegant ones now, but
it sure gives you a lot of control.

There's a phase vocoder in Peak's DSP menu, but I haven't had reason to
play with it.




--
Jay Rose CAS
tutorials and other sound goodies at dplay.com
email is "jay@" plus the dot-com in the previous line.
 >> Stay informed about: Slow motion and sync audio 

from avid.com:

"Audio IO

48 kHz, 44.1 kHz, and 32 kHz (hardware supports up to 96 kHz)
16 or 24-bit resolution
8 channels ADAT audio I/O or stereo Toslink optical S/PDIF"

so the software doesn´t support 96k I guess....

frank.


On 27 Okt., 13:37, Jakob van Oosterhout wrote:
> 25-10-2007 22:28 "wildt®ax" :
>
> > Adrenaline AVIDs handle 96k fine.
>
> Huh? How?
> They are specified for 44.1 or 48K, not 96. They may be able to convert to
> 48 upon import, but that is not the same as being able to 'handle' it, IMHO.
>
> J, NL
 >> Stay informed about: Slow motion and sync audio 

25-10-2007 22:28 "wildt®ax" :

> Adrenaline AVIDs handle 96k fine.

Huh? How?
They are specified for 44.1 or 48K, not 96. They may be able to convert to
48 upon import, but that is not the same as being able to 'handle' it, IMHO.

J, NL
 >> Stay informed about: Slow motion and sync audio 

On Oct 26, 5:50 pm, wildt®ax wrote:
> Is there a speciffic program you have in mind?
>
> frank.

You can use IRCAM's "AudioSculpt" or MIT's "csound" for instance as
well as Tom Erbe's "SoundHack"

Fernando
 >> Stay informed about: Slow motion and sync audio