AAC Performance Tests
Impairment Scale
Grade
Diffgrade
Degradation
5.0
-0.0
Imperceptible
4.0
-1.0
Perceptible but not annoying
3.0
-2.0
Slightly annoying
2.0
-3.0
Annoying
1.0
-4.0
Very annoying
Formal Subjective Tests
5-channel, 64kb/s/ch MPEG-2 Test, 1996
2-channel, 48 and 64 kb/s/ch tests
MPEG-2, 1997
Communications Research Centre, 1998
2-channel, 9 and 12 kb/s/ch MPEG-4, 1998
Performance Summary
AAC is first Coder to satisfy requirements for ITU-R Broadcast Quality
5-channel, AAC at 320 kb/s comparable to
MPEG-2 Layer II BC at 640 kb/s
Stereo, AAC at 96 kb/s comparable to
PAC at 128 kb/s
AC3 at 160 kb/s
MPEG-2 Layer II at 192 kb/s
Stereo 128kbps
AAC score -0.5 (not annoying)
Layer III score -1.7 (slightly annoying)
AC3 score -2.1 (annoying)
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gjm
- last update 02/08/1999
