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Creating Audio

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What...

When working with digital audio it is important to understand the difference between 'codecs' and 'wrappers'. The term codec refers to the algorithm used to encode and decode the raw audio data whereas the wrapper (or container) is the file format that wraps the raw audio data along with other data such as metadata or album artwork images for example.

Why...

Codecs can be uncompressed (such as Linear PCM), lossy-compressed (such as MP3) or losslessy-compressed (such as FLAC). Selecting an appropriate codec is important as it has an effect on how much raw audio data is retained. Uncompressed and losslessy compressed will retain the original audio data whereas compressed codecs irretrievably lose audio data from the outset. A side effect of lossy audio data compression is the introduction of anomalies in the spectral and time domains. Compressed formats are therefore not suitable for archival purposes or for projects where audio fidelity is important.

How...

If you are likely to deposit your images with an archive such as The Modern Records Centre we recommend the following

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  • set the sample rate (the quality of reproducing an analogue signal as a digital signal) should be set to at least 48kHz, though 96kHz is preferable
  • set the bit depth (the range of values available per sample) at 24 bit
  • set the audio codec to Linear PCM (Pulse Code Modulated)
  • save the wrapper file as a Broadcast Wave Format (BWF) (.wav) audio file
  • if required, produce a smaller derivative file at a lower sample rate and bit depth for sharing. A Moving Picture Experts Group Layer 3 (MP3) compression file (.mp3) is suitable for this