5. File Transformations

Audio-Visual Data Transformations (slides 38–39)

Transformations happen every now and then in the digital audio-visual world.

It’s most important that the archives are able to manage the file formats they are preserving. In addition, the archive should be able to transform one file format into another when ever needed. This includes the production of access and diffusion files.

The five steps to achieve are:

  1. demultiplex: “open” the container;
  2. decode: read the data using the correct codec;
  3. filter: transform the data from one raw format into another;
  4. encode: write the data using the correct codec;
  5. multiplex: “close” the container.
Audio Example (slide 40)

A QuickTime (.mov) container, holding WAVE audio in a mezzanine format, is transformed into a MP4 container, holding AAC compressed audio for today’s digital world.

Video Example (slide 41)

A QuickTime (.mov) container, holding video ProRes 422 HQ (also a mezzanine format), is transformed into a MP4 container, holding H.264 compressed video for today’s digital world.

Audio-Visual Example (slide 42)

The previous audio and video examples combined in one single file.