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2. Audio compression formats
2.1 Principles
Audio data reduction includes :
reducing the amount of information resulting from the native digital format. For example, we can reduce either the sampling frequency, and therefore the number of coded samples, or the audio frequency band. We can also reduce the coding depth of each sample, from 24 bits to 20 bits, 16 bits or 8 bits;
compression of the remaining data using specific algorithms.
The elimination of redundancy in audio makes particular use of the phenomenon of frequency masking. When there is more energy in one frequency band, for example at 1 kHz, the ear seems to protect itself from overload by failing to register energy in neighboring bands...
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Audio compression formats
Still image compression formats
Bibliography
Principles
- (1) - GOUYET (J.-N.) - Systèmes audio et vidéo numériques. - Codage de source – Réduction de débit, Chap. 10, Institut national de l'audiovisuel, Techniques et production audiovisuelles, Paris, ISBN 2-86938-030-5 (1993).
Audio
Standards and norms
Audio
- Information technology – Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s – Part 3: Audio http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22412 - ISO/IEC 11172-3 - 1993
- Information technology – Generic coding of moving pictures and associated audio information – Part 3: Audio http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=22991...
Directory
Organizations – Federations – Associations (non-exhaustive list)
ATSC (Advanced Television Systems Committee) http://www.atsc.org/
DCI (Digital Cinema Initiatives LLC) http://www.dcimovies.com/
EBU (European Broadcasting Union)...
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