Description

This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.

44 Tell me more about sound quality. How do you assess that? (MPEG Audio Layer-3 Applications)

Today, there is no alternative to expensive listening tests. During the ISO-
MPEG process, a number of international listening tests have been
performed, with a lot of trained listeners. All these tests used the "triple
stimulus, hidden reference" method and the "CCIR impairment scale" to
assess the sound quality.
The listening sequence is "ABC", with A = original, BC = pair of original
/ coded signal with random sequence, and the listener has to evaluate both
B and C with a number between 1.0 and 5.0. The meaning of these values
is:
5.0 = transparent (this should be the original signal)
4.0 = perceptible, but not annoying (first differences noticable)
3.0 = slightly annoying
2.0 = annoying
1.0 = very annoying

 

Continue to:

• prev: 43 Wait a second! I understand that Layer-3 has been an important asset to the MPEG-1 standard, to address the high-quality low bitrate applications. With the advent of the "low sample rate extension (LSF)" in MPEG-2, is it still necessary to rely on Layer-3 to achieve a high-quality sound at low bitrates? (MPEG Audio Layer-3 Applications)
• Index
• next: 45 Is there really no alternative to listening tests? (MPEG Audio Layer-3 Applications)

Share and Enjoy

Tags

pc, MPEG, compression, video, audio, mp3, layers, bitstream, software, books, publications, technology, standard, shareware, free