User Manual

Multichannel Monitoring Tutorial Booklet (M2TB) rev. 3.5.2

Masataka Nakahara : SONA Corporation

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2-2-2. Compression methods

Compression methods can be broadly divided into two types; lossy compression and lossless

compression.

With lossy compression, the original signal cannot be recovered in its entirety from the compressed signal

that is recorded; i.e., this is irreversible compression.

This method generally takes advantage of psychoacoustic phenomena to lower the redundancy of the

original signal, thus compressing it.

Lossless compression allows the original signal to be completely recovered from the compressed signal

that is recorded; i.e., this is reversible compression. This method is used to compress files on a computer.

It uses mathematical means to lower the redundancy of the original signal, compressing it.

Thus, lossless compression delivers a lower compression ratio than lossy compression.

Examples of lossy Method Dolby AC-3, DTS coherent acoustic, ATRAC, MPEG-2(AAC), etc.

compression Media Film, DVD-Video, digital broadcast, games, etc.

Examples of lossless Method MLP (PPCM: Packed PCM), DST (Direct Stream Transfer)

compression Media DVD-Audio, Super Audio CD

Examples of uncompressed formats

Media CH Encoding method fs [Hz] Qb [bit] Bitrate [bps]

Dynamic range

[dB]

CD 2ch LPCM 44.1k 16 1.4112M 96dB

DVD-Video 1 - 8ch* LPCM 48k, 96k 16, 20, 24 Max 6.144M Max 144dB

1 - 44.1k, 88.2k, 176.4k,

DVD-Audio

5.1(6)ch**

LPCM

48k, 96k, 192k

16, 20, 24 Max 9.6M Max 144dB

DSD

Super Audio CD 2ch

(Direct Stream Digital)

2.8224M 1 5.6448M

More than

120dB ***

Within a maximum of 6.144 Mbps, “fs” and “Qb” can be specified in a scalable manner according to the number of

channels.

Example) In the case of two-channel, maximum 96 kHz x 24-bit x 2 channels = 4,608 Mbps < 6.144 Mbps

** Within a maximum of 9.6 Mbps, “fs” and “Qb” can be specified in a scalable manner according to the number of channels.

However, only one or two channels are possible for fs=176.4k or 192k.

Examples) One or two channels; max. 192 kHz/24-bit, 4 ch; max. 96 kHz/20-bit, 5.1(6)ch; max. 96 kHz/16-bit

***

Va l ue in the audible bandwidth. Includes the effect of noise shaping from Delta-Sigma modulation.

[Table 3-1] Examples of uncompressed formats