Antex electronic SX-33 Benutzerhandbuch

38

ISO/MPEG supports several compression rates and encodes
flags that describe the audio data.  The flags and other options
are selected by typing MPEG with

[extensions]

 switches in the

Format text box of the DOS demo. (The bitrates in the Windows
demo are selected by double-clicking on MPEG in the
Compression list to get a bitrate drop-down menu)

MPEG[extensions]"

where [extensions] is a concatenation (in any order) of:

/L =1 (layer 1) or

=2 (layer 2),

=44100 or
=48000 (to specify the sample
rate),

/M =st (mode = stereo)

=js (mode = joint-stereo) or
=dc (mode = dual channel) or
=sc (mode = single channel)

/kB =Kbits per second per channel

/E =1 (crc error checking) or

=0 (no crc error checking),

/C =1 (copyright protected) or

=0 (not copyright protected),

/O=1 (original) or

=0 (copy),

/Em =0 (no emphasis) or

=1 (emphasis 50/15ms) or
=2 (reserved)
=3 (CCITT J17)

For example to get a 5.5:1 compression ratio, layer II and joint
stereo in a 44.1kHz file:

1.  Select 44100 from the SampleRate menu

2.  Click on the text box lableled Format

3. Type 

MPEG/kb=128/m=js/l=2

MPEG-1 has a range of compression ratios that are user select-
able. The compression ratio selected will depend upon the audio
quality required.  The MPEG-1 format specifies the compression
ratio by defining the desired bitrate. The compression ratio ob-
tained for a given output bitrate therefore changes with sample
rate.