FPS, Sample Rate and Pitch Correction


A few weeks back a question was posed on one of the industry forums about to sync recorded audio to a shot that was intended for slow motion. From that, I created a spreadsheet that would do the calculations including semitones needed to keep original pitch. The percentage or semitones can be used in pitch shift audio plug-in if desired.

There is a difference on how the WAV file declared sample rate in order for this to work in Media Composer.  For example, if recording 24.000fps on set with the intent to post at 23.976,the recorder would be set to 48.048kHz. But if the files have already been recorded at 48.000kHz, then you need to reset the sample rate to 47.952kHz using an application like Wave Agent from Sound Devices. The pullup or down would then be performed by the BWF import process. This previous blog shows sample rate to project for “normal” shooting rates. This will not work with the BWF/iXML AMA plug-in, as that does not support pullup/down workflows.

This spreadsheet calculates those values as well as the more offbeat rates that may be used when shooting for slow motion or speed up with different frame rates than than the intended playback rate. Download the Microsoft Excel spreadsheet here.  For those that do not have Microsoft Excel, this should open fine in Google docs or open source alternatives.

Don’t mess with the formulas!

Update 6/30/2014: You can now access the spreadsheet as a Google Sheet. You may need to sign in with a Google account to work with the spreadsheet online.

Update 10/26/2014: It has been brought to my attention that some field are not properly displaying when opened in “Numbers“. Specifically the sample rate fields. Make sure that these fields are set to 5 digits.

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