The golden rule is to have very good quality sound recordings, whether that is pre-recorded audio files, or audio you've recorded yourself. There are different considerations across your production pipeline (like scratch versus finished), editing concerns, and listening-only needs.


CHOOSE EDITING QUALITY SOUND FILES

File formats: WAV, AIF
  • Uncompressed is required. Both WAV and AIFF are uncompressed formats.
  • File formats indicate their type of compression.
  • These file types contain soundwaves in their original, analog form. These are converted to a digital form by the PCM (pulse code modulation) codec for use in digital systems.
Bit-size: 24-bit
  • 16-bit is acceptable for some sound effects, backgrounds and atmosphere, but always aim for 24-bit.
  • 32-bit is not necessary for general film use. It's certainly a higher amount of data, but we don't even use or hear that difference in standard level (not feature film studio) media productions. It also creates much bigger file sizes, which we like to avoid.

Sample rate: 192 kHz  This is the amount of data flow. (see explanations below)

  • Kilohertz (kHz) is the frequency of the sound wave. Soundwaves are part of WAV and AIF files.
  • Kilobytes (kbps) is the frequency of data per second. Mp3/MP4 do not contain atual soundwaves, but sound data.

Channels: mono or stereo is acceptable. 

Mono is one microphone source recording the sound.
True stereo is recorded with left and right channels mic sources. Each channel can be treated as it's own sound file. Stereo is very important if the end-use of the sound recording needs to capture true spatial qualities. This might be for actual spaces or for a group music performance, for example. 


CHOOSE SCRATCH TRACK QUALITY AUDIO FILES

These are temporary audio tracks and are generally used without any significant editing. Just because these are temporary does not mean that you should use garbage quality audio.

File formats, BEST: WAV, AIF
File formats, ACCEPTABLE but cannot be edited (see note below): MP3, MP4 / AAC, Ogg
Bit-size: 16 and 24-bit
  • 8-bit is a last ditch, very temporary placeholder type of sound file. But just avoid it.

Bitrate: 128 kbps for MP3, MP4; 128 - 196 kHz for WAV and AIFF

  • Kilohertz (kHz) is the frequency of the sound wave. Soundwaves are part of WAV and AIF files.
  • Kilobytes (kbps) is the frequency of data per second. Mp3/MP4 do not contain actual soundwaves, but sound data.

Channels: mono or stereo is acceptable. Mono is one microphone source recording the sound. True stereo is recorded with left and right channels mic sources. Stereo is very important if the end-use of the sound recording needs to have true spatial qualities.

Scratch Track audio file pops and clicks? Compressed files, like MP3s and MP4s, will often end up with odd pops and clicks if editing cuts are made on them. This is a result of the lossy, compression processes leaving frames that are "buffer" frames and don't have actual audio data in them. Because of this, they are not edited beyond volume changes, simple fx (reverb) and fades. 


FILE FORMAT TYPES (primary ones)

See a list of Adobe's supported audio file formats. There are many, many types of files, but there are just a few that are commonly used in production.
 
UNCOMPRESSED FILE FORMATS, LOSSLESS QUALITY
WAV (waveform). Created by Microsoft. 
AIF / AIFF (audio interchange file format). Created by Apple. 
FLAC is an Open Source format that allows for an extremely high amount of data. The ability to record and edit it is depends on the device system. Adobe Audition supports this.

COMPRESSED FILE FORMATS, LOSSY QUALITY
MP3 Created by Microsoft for listening via sound playback devices. Slightly smaller file size than Mp4/AAC
MP4 / AAC  (Advanced Audio Coding) Created by Apple for listening via sound playback devices. AAC is a newer variation of MP4. Slightly better sound than MP3.
Ogg  Is an Open Source file format. It can store more audio channels than MP3, but can also be a big battery / energy hog. It is also not read across all devices, so it creates a limitation on use.


See the next page for terminology definitions for: compressed, uncompressed, lossless, lossy, kilohertz, bit depth, sample rate and bit rate.

Last modified: Monday, 6 March 2023, 4:06 PM