Audio File Types: Bit Depth, Sample Rate

Only use uncompressed Broadcast Wave (.wav) linear PCM files, with a bit depth of 24 for all deliverable items and original recordings. For original field recordings, there are benefits to using 32-bit floating point, but final mixes should reference 24 bits, using a “zero VU” reference of -20 dBFS.

As to sample rate, should finishing work be done at 96 kHz—which is not a bad idea—a duplicate set of deliverable elements must be made to the industry-standard sample rate of 48 kHz. As a rule, one could hazard a guess that 99% of all movies only use 24/48 for all production and post-production recordings.

Note that it is also standard and recommended practice to make all transfers from analog masters (multitrack or mag film) at the 96 kHz sample rate, to ensure the highest possible resolution of audio remastering. This should be done regardless of the quality of the source material—even optical film, when it is fairly impossible to tell the difference between 48 kHz and 96 kHz transfers.